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Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY
APPLIED TO AN ISOLATED CARBONATE PLATFORM REEF COMPLEX;
LLUCMAJOR PLATFORM, MALLORCA
DAVIES, E.J and RATCLIFFE, K.T.
Chemostrat Limited, Unit 1 Ravenscroft Court, Buttington Cross Enterprise Park, Welshpool, SY21 8SL, UK
MONTGOMERY, P.
Chevron Upstream Europe, Seafield House, Hill of Rubislaw, Aberdeen, AB15 6XL, UK
POMAR, L.
Universitat de les Illes Balears, Palma de Mallorca, Spain
ELLWOOD, B.B.
Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisianna 70803, USA
WRAY, D.S.
School of Science, University of Greenwich, Chatham Maritime, Kent, ME4 4TB, UK
ABSTRACT
Inorganic whole rock geochemical and magnetic susceptibility (χ data have been gathered from 7 sections
through the Upper Miocene reef complexes of the Llucmajor Platform, Mallorca. The aim of acquiring these
data is to determine what chronostratigraphic information a combination of magnetic susceptibility stratigraphy
(MSS) and chemostratigraphy can provide in reef complexes of a carbonate platform with no nearby source of
terrigenous material.
χ values display short-term cyclical fluctuations, maximum values commonly being associated with the upper
bounding surfaces of sigmoids and sigmoid sets, the building blocks of the Llucmajor reef complexes. Values of
χ are low at the bases of the sigmoids, they reach a maximum at the top of the sigmoids, and then fall rapidly to
the base of the next sigmoid, indicating a base level control on χ values. No longer-term variation in the χ values
have been identified that would enable differentiation of an old reef complex from one that is demonstrably
younger in the cliff sections and there is no apparent facies control on χ values. While, the elemental data do not
vary in response to base level fluctuations and therefore do not define stratigraphic surfaces, they do show long
term variations, enabling reef complexes of differing ages to be geochemically characterized, the key to defining
chemostratigraphic schemes. The elements used to characterize different age reef complexes are Cr, Zr, Al2O3,
TiO2, Ga, Rb, which are controlled by changes in the amount and composition of wind-blown terrigenous
material and tuffaceous material. As such, the changes are chronostratigraphic events on the scale of the study
intervals here. Although the two datasets used are both ultimately controlled by the mineral composition of the
sediments, it has proved impossible to find a direct link between the elemental data and χ values.
Despite the lack of an understanding of the relationship between whole rock geochemistry and χ values for this
dataset, they clearly provide a means to a) define stratal surfaces that relate to base level fluctuation and b)
recognize reef complexes deposited at different times. Therefore, the combined approach adopted here for the
Llucmajor reef complex has the potential to provide cross-facies chronostratigraphic correlations in detached
platform carbonate settings and since both methods can be applied to core and cuttings samples, the approach
could work in subsurface settings where samples would be from well-bores.
KEY WORDS: Stratigraphy, Chemostratigraphy, Magnetic susceptibility (χ), carbonate platform, Llucmajor
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
INTRODUCTION Increasingly, “alternative” stratigraphic
methods, such as whole rock elemental
chemostratigraphy and magnetic susceptibility
stratigraphy (MSS), are being used to provide
stratigraphic correlation frameworks (see
Ratcliffe and Zaitlin, 2010 for review of
chemostratigraphic and MSS methods). Both
stratigraphic methods are being used in the
petroleum industry to help construct
correlations between well bores and therefore
enhance understanding of hydrocarbon
reservoirs. However, in most published
accounts the resultant stratigraphic correlations
cannot be compared against irrefutable
stratigraphic surface correlation that has been
derived from more conventional approaches or
from visual / physical correlations.
Furthermore, although MSS has been applied
to relatively pure carbonate lithologies,
including detached platform settings (da Silva
et al., 2009, Stage, 2001, Ellwood et al.,
2010a, 2010b), there are few published
accounts of chemostratigraphic applications on
pure carbonates (Wray and Gale, 2006) and
none on isolated carbonate platforms have
been found. The paucity of published
chemostratigraphic examples in carbonate
lithologies probably reflects the fact that most
accounts of chemostratigraphy in the literature
relate the elemental data to siliciclastic
components of the sediments (e.g. Hildred et
al., 2010, Pearce et al., 2005, Wright et al.,
2010 and Ver Straeten et al., 2011). The only
non-carbonate input into the sediments of
detached platform systems is wind-blown
material and while there are published
accounts of the mineralogy of wind-blown
detritus (e.g. Stuut, et al., 2009, Saukel, et al.,
2011) there is little published information on
the whole rock inorganic geochemistry of such
sediments (e.g. Castillo et al., 2008, Wang et
al., 2010) and no accounts have been found
using elemental data in wind-blown sediments
to make stratigraphic implications. It is
therefore questionable as to whether
chemostratigraphy, which is typically reliant
upon changes in the amounts and types of
terrigenous material, can be realistically used
in a detached carbonate platform setting.
In order to test the efficacy of the stratigraphic
methods in pure carbonate lithologies,
chemostratigraphy and MSS are applied to
Upper Miocene reef complexes of the
Llucmajor Platform (Figures 1 and 2). These
reef complexes crop out on the southern sea-
cliffs of the Balearic island of Mallorca and
have been extensively studied in the past,
being a “classic” example of how reef
complexes respond to sea level fluctuations
(Pomar and Ward 1994, 1995).
Although the Llucmajor reef complexes are
not strictly detached carbonate platforms since
they are attached to small emergent areas, the
emergent areas are carbonate lithologies and
therefore provided no siliciclastic detritus. The
almost perfect exposure and published studies
provides an exceptionally robust
understanding of their facies architecture and
Figure 1. Location map. Upper left inset shows location
of Mallorca in the Western Mediterranean Sea. Main map displays outline of Mallorca and the location of the reef platforms (light grey), carbonate highlands (dark grey.)
CB-TV denotes the extent of the cliff section displayed in Figure 2.
TVMALLORCA
50km
Reef platforms
Reef platform margin
Highlands
(Alpine thrust belts)
39 30’ N
3 EMarratxi
platform
Alcudia
platform
Santtanyi
platform
Cap Blanc
(CB)
Palma
basinLlucmajor
platform
Mallorca
500km
Cliff section in Figure 2
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
0 321 4
km
CB
Vallgornera
TVPC
PNC
CCCOSGW
Reef tract
Line of projection
1
CB SGW CO CC PNC TVPC
100m
50m
0m
Cala PiCala Beltran
Vallgornera
Cap Blanc
Pleistoceneeolianite
Pleistoceneeolianite
Pleistoceneeolianite
Pliocene post-reef grainstone
lagoon
lagoonreef
slope
stratigraphy, making them an ideal testing
ground for MSS and chemostratigraphy.
Specifically, they provide an opportunity to
see how elemental geochemistry and magnetic
susceptibility signals respond to changing sea
level in a well understood prograding reef
complex that is part of an isolated carbonate
platform with the only non-carbonate material
being wind-blown terrigenous and
volcanogenic detritus.
Figure 2. Sea cliffs of the Cap Blanc region. Lower right inset is an enlarged map of the SE coastline of Mallorca (see
Figure 1 for position of this coastline), with the location of each study interval displayed. The lower left photograph
shows the Cap Blanc to Cala Carril (cc) cliff section with facies interpretation over lain; horizontal length is 2 km.
Top panel is a composite sketch of the sea cliffs of from Cap Blanc to Vallgornera (TV), with vertical black bars
showing the approximate location of the sections referred to in the text (CB, SGW, CC, CO PNC and TV) and key
striatal surfaces shown in black.
SATorre(CBSection)
CalaCarril(CCSection)
Punta Negra(PNCSection)
Fore ReefSlope
ReefCoreReef
Core
Inner
Lagoon
Inner
Lagoon
Outer
Lagoon
Outer
LagoonOuter
Lagoon
Reef fa
cies
Reef fa
cies
Reef fa
cies
Lagoonal
Lagoonal
Lagoonal
Fore
reef fa
cies
Fore
reef fa
cies
sb
Ci
sbsb
sb
dls
2km0.3km 2km
0.3km
10m
10
m
Pliestocene
Pliestocene
SATorre(CBSection)
CalaCarril(CCSection)
Punta Negra(PNCSection)
Pliestocene
Pliestocene
Figure 3. Stratigraphic correlation of reef complexes from Punta Negra (PNC Section) to Cap Blanc (CB Section)
3a) probable correlation that would result if perfect exposure did not exist, or the only data available were wireline
logs and cuttings, i.e. well-bore data. 3b) Actual correlation, based upon interpretations of Pomar and Ward (1994).
Redrawn from Pomar and Ward (1995)
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
Being able to chronostratigraphically correlate
between well bores in subsurface carbonate
platforms is exceptionally difficult due to lack
of preserved diagnostic fauna and flora, strong
facies control and lack of contiguous surfaces
that can be recognized in the subsurface.
Figure 3a demonstrates how a correlation from
Punta Negra to Cap Blanc in the sea cliffs of
this paper may look if data were only available
from the subsurface (wireline logs and cuttings
samples). Figure 3b shows the actual
interpretation placed on the same section that
is afforded by the well exposed nature of the
sea cliffs highlighting the issues faced when
working with reef complexes in the
subsurface. The aim of this paper is to
demonstrate how the application of
chemostratigraphy and MSS could help move
a subsurface correlation toward the
interpretation shown in Figure 3b, rather than
Figure 3a. Although specific to the Llucmajor
Platform, the methods described here are
equally applicable to any setting where the
lithologies are predominantly pure carbonates.
Therefore, this work demonstrates that a
combined MSS and chemostratigraphy
approach can provide high resolution
stratigraphic correlation in any detached
carbonate platform. Both methods are proven
to work on well-bore cuttings samples
(Ellwood et al. 2001, Ratcliffe et al. 2010) and
therefore, the applications here can be applied
to creating stratigraphic frameworks in
subsurface settings.
Study Material The sea-cliff exposures of Upper Miocene reef
complexes on the southern coast of Mallorca
that are the focus for this paper (Figure 1) are
part of the Llucmajor Platform, one of several
reef complexes that developed in late Miocene
times in the region of the present day Balearic
Islands. For this paper, the carbonates near the
Cap Blanc area of southern Mallorca are
selected because of their excellent exposure
and their well-documented depositional
models and high resolution architectural facies
model (Pomar 1991, 1993, Pomar and Ward
1994, Pomar et al., 1996) (Figures 2 and 4).
The Llucmajor Platform has been extensively
studied and described by Pomar and Ward,
(1994; 1995; 1999) and Pomar et al. (1996).
The sediments analysed here comprise
proximal fore reef slope facies, reef core facies
and lagoonal facies. The fore reef facies are
characterized by seaward-dipping clinoforms
and are composed of skeletal floatstones to
grainstones and packstones with coral,
rhodolith and mollusc fragments. Reef core
facies have characteristic sigmoidal bedding
and are composed of skeletal grainstone
/packstone/wackestone within a coral
framework that is composed of massive coral
reefs. Sediments from lagoonal facies are
skeletal grainstones and packstones with
lenses of coral breccia and patch reefs in outer
lagoonal settings to mudstones-wackestones
and stromatolites in inner settings (Pomar,
1991; Pomar and Ward, 1994, 1995, 1999, and
Pomar et al. 1996.).
The study sections in this paper are a subset of
those described by Pomar and Ward (1999)
and the section names (CB, SGW etc.) refer to
the measured sections of those authors. Figure
4 displays the hierarchical stacking of
sigmoidal depositional units described by
Pomar and Ward (1994). The sigmoid is the
basic building block, representing a
depositional sequence related to the highest-
frequency sea-level cycle recognized (Figure
4A). Sigmoids stack in sets of sigmoids as
seen on the sea cliffs on Mallorca (Figure 4B)
and sigmoid sets stack in cosets of sigmoids
(Figure 4C). The sigmoid cosets stack into
megasets, three of which build the whole
Llucmajor Platform (Figure 4D). The reef-
crest line displayed on Figures 4A-4E (Pomar,
1991) follows the trajectory of successive
positions of the reef crest and it reflects the
amplitude of sea-level fluctuations.
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
Figure 4. Facies architecture of the Llucmajor Platform. (A) The sigmoid represents a basic depositional sequence
related to the highest-frequency sea-level cycle. (B) Sigmoids stack in sets of sigmoids as seen on the sea cliffs on
Mallorca. (C) Sets stack in cosets of sigmoids (inset box outlined by red dashed line corresponds to B). (D) Cosets
stack in megasets and three megasets of sigmoids build up the whole Llucmajor Platform; sb: sequence boundary;
dls: downlap surface; ci: condensed interval. (E) Comparison between the reef-crest line, established from the
megasets of sigmoids in the Mallorca’s Llucmajor Platform, and the composite smoothed short-term oxygen
isotope record from Abreu and Haddad (1998), as a proxy for 3rd
-order eustatic sea-level cycles. (F) Wheeler
diagram of Sea cliff section in C. Redrawn from Pomar and Ward (1994).
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
The reef-crest line, established from the
megasets in the Mallorca’s Llucmajor
Platform, compares closely with the composite
smoothed short-term oxygen isotope record
from Abreu and Haddad (1998) (Figure 4E),
which is a proxy for 3rd
-order eustatic sea-level
cycles. Accordingly, the sigmoid cosets
represent 4th-order cycles, sigmoid sets
correspond to 5th
-order cycles, and sigmoids to
6th-order cycles. The bounding surfaces of the
sigmoids, sigmoid sets, sigmoid cosets and
sigmoid megasets are therefore 6th, 5
th, 4
th, and
3rd
order sequence boundaries respectively.
Figure 4F is a Wheeler diagram constructed
from interpretation of the cliff section shown
in Figures 2 and Figure 4C.
The reef complexes in the Llucmajor Platform
area developed on a small emergent platform
with no fluvial input, resulting in the
sediments being almost pure carbonate (calcite
and dolomite). The only impurities are wind-
blown terrigenous detritus, which is a
ubiquitous feature of all depositional settings,
and wind-blown volcanic ash, with a least one
sanidine biotite-rich tuff being recorded in the
sequence. (Al2O3 + SiO2) generally accounts
for <2% of the major elements analysed and
(CaO + MgO) accounts for > 97% of the major
elements (Table 2), indicating the almost pure
carbonate nature of the study interval
sediments. Unfortunately, after analysis for
this paper, plus analysis for carbon and oxygen
isotope analysis (that were not available at the
time this paper was prepared) insufficient
sample material remained to allow X-Ray
diffraction quantification of the non-carbonate
fraction of the lithologies.
Samples were taken from 7 cliff sections
extending from Vallgornera in the east to Cap
Blanc in the west (Figures 1, 2 and 4). A total
of 267 samples were collected and analysed
from the 7 sections (Table 1, Figure 2).
Samples were taken at an average spacing of
1m, although accessibility and ease of taking
plugs results in variation in sample spacing
from a maximum of 2.5m and a minimum of
0.3m. Each sample collected is a 1” diameter
core plug, c. 1-2” in length. Where possible,
the plug was taken to avoid large allochems,
targeting sediments between coral colonies in
the reef complexes. All surficial contamination
was removed prior to approximately half of
the plug being disaggregated. Half of the
disaggregated chips were analysed for
magnetic susceptibility and the remainder was
ground in an agate ball mill prior to being
prepared for inductively coupled plasma
optical emission spectrometry (ICP OES) and
inductively coupled plasma mass spectrometry
(ICP MS) analyses. The remaining material
has been sent for stable isotope analysis,
although the results are not available at the
time this paper was written.
Table 1 Sample Summary
Section Thickness
(m) Sample
No
Av sample spacing
CB 58.6 53 1.11
SGW 26.75 30 0.89
CO 60 41 1.46
CC 53.6 46 1.17
PNC 44 36 1.22
PC 26.1 32 0.82
TV 27.94 29 0.96
METHODOLOGIES
Magnetic Susceptibility Stratigraphy
All mineral grains are “susceptible” to
becoming magnetized in the presence of a
magnetic field, and the low-field, mass-
specific bulk magnetic susceptibility (χ is an
indicator of the strength of this transient
magnetism within a material sample (Nagata,
1961). Magnetizable materials in sediments
include not only the ferrimagnetic minerals
(such as magnetite or greigite), but also any
other less magnetic, or paramagnetic,
compounds. The important paramagnetic
minerals in marine sediments include clays
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
Table 2. Average element abundances in 3 main facies. Element abundance is expressed as a
percentage of the major elements summed. X values are average values for each facies.
(particularly chlorite, smectite and illite),
ferromagnesian silicates (biotite, tourmaline,
pyroxene and amphiboles), iron sulfides
(pyrite and marcasite), iron carbonates
(siderite and ankerite), and other iron- and
magnesium-bearing minerals (Ellwood et al.,
1989; Ellwood et al., 2000). Calcite, quartz,
and organic compounds typically acquire a
very weak negative χ when placed in inducing
magnetic fields; that is, their acquired χ is
opposed to the low magnetic field applied. The
presence of these diamagnetic minerals
reduces the χ in a sample, but because
diamagnetism is so small by many orders of
magnitude for an equivalent mass sample,
even very small amounts of paramagnetic
minerals will usually dominate over
diamagnetic components. Therefore, in marine
sediments, χ is generally considered to be an
indicator of iron, ferromagnesian, or clay-
mineral concentration (Ellwood et al., 2000;
Ellwood et al., 2010a, 2010b). In an isolated
carbonate setting, such as Llucmajor Platform,
χ values can be expected to relate to the
amount of terrigenous material in the
limestone lithologies (da Silva et al., 2009)
and should therefore be related to the whole
rock inorganic geochemistry.
All measurements reported herein were
performed using the susceptibility bridge at
Louisiana State University (LSU). It is
calibrated using standard salts for which
values are reported in the Handbook of
Physics and Chemistry and by Swartzendruber
(1992). The LSU bridge is very sensitive, is
easy and fast to use, and the measurement coil
is optimized for small samples, making it ideal
for measuring large numbers of samples
rapidly. χ is reported in terms of sample mass
because it is much easier and faster to measure
with high precision than is volume (Ellwood et
al., 1988b). Each sample is measured three
times and the mean and standard deviation of
these measurements is calculated. The mean of
these measurements is reported here.
Chemostratigraphy
Chemostratigraphy, as used here, refers to the
development of stratigraphies using variations
in elemental composition. Typically, the aim
of a chemostratigraphic approach is to identify
elements and element ratios that change
through time and which therefore enable
sediments of the same age to be correlated, or
differentiated from sediments that are
asynchronous. Published accounts of
chemostratigraphy are largely from petroleum
basins and are mostly on fluvial siliciclastic
systems and shale resource plays. In fluvial
settings, the elemental data are typically used
to recognize changes in paleoclimate (Pearce
2005, Ratcliffe 2010), changes in sedimentary
facies and changes in sediment provenance
Facies Average
(Al2O3+SiO2) Average
MgO Average
CaO
Average (CaO
+MgO)
Average Average
Calculated Calculated (m3/kg)
Dolomite Calcite
Lagoonal 1.4 13 83 96 18 79 6.40E-
09
Reef Core
0.7 29 68 97 41 57 4.70E-
09
Fore Reef
0.5 34 63 97 29 69 8.10E-
09
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
(Hildred 2010, Wright 2010, Ramkumar, et al.,
2011). In shale resource plays, the elemental
data are commonly used to recognize
terrigenous material influx and content (Algeo
et al., 2004, Soau, 2010, Ver Straeten et al.,
2011,) and as a proxy for bottom water
conditions during deposition (Tribovillard et
al., 2006, Rowe et al., 2012). These changes
are then used to build a stratigraphic
framework and provide stratigraphic
correlations. In the case of the Llucmajor
Platform carbonates, the vast majority of the
rock volume is calcite and dolomite, with CaO
plus MgO accounting for an average of 97% of
the major element total expressed as weight
percentage. Therefore, the aim here is to
determine whether changes in such minor
amount of non-carbonate material can be
detected using elemental geochemistry and
whether such changes show systematic
changes through time that would have the
potential to devise stratigraphic correlations in
a similar manner to how fluvial workers use
the technique.
In order to carry out chemostratigraphic
studies, data for a wide array of major and
trace element are required and require
instrumentation that can detect and quantify
these trace elements at very low abundances.
For this study, the elemental data have been
acquired using inductively couple plasma
optical emission spectrometry (ICP OES) and
inductively couple plasma mass spectrometry
(ICP MS), following a Li-metaborate fusion
(Jarvis and Jarvis, 1995). This methodology
provides data for 10 major elements (SiO2,
TiO2, Al2O3, Fe2O3, MgO, MnO, CaO, Na2O,
K2O, P2O5), 25 trace elements (Ba, Be, Bi, Co,
Cr, Cs, Cu, Ga, Hf, Mo, Nb, Ni, Pb, Rb, Sn,
Sr, Ta, Tl, Th, U, V, W, Y, Zn, Zr);and 14 rare
earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd,
Tb, Ho, Dy, Er, Tm, Yb, Lu).
RESULTS
Magnetic susceptibility (χ )
χ values for three sections (CB, CO and CC)
are displayed on Figure 5, together with the
stratigraphic interpretation taken from the cliff
section (Pomar and Ward 1994). It is apparent
from χ curves that there are numerous cyclical
fluctuations in the χ values that show a
gradual upward increase to a local maximum,
followed by a sharp upward decrease to the
base of the next cycle. Within the CB sections,
these are generally on the scale of 5-10m,
which is the same magnitude as the basic
sigmoid building block described by Pomar
and Ward (1994) and displayed in Figure 4A.
Maxima in χ values are very evidently
associated with condensed intervals (Ci) and
downlap surfaces (DLS) and some sequence
boundaries (sb). Not all sequence boundaries
appear to be defined by χ cycle tops (e.g. sb2
in CB Section). The cycles in the CC Section
are less clearly developed, but this may relate
to sample distribution (which in turn related to
accessible sample points). Although the χ
values show peaks at upper bounding surfaces,
the magnitude of the peaks do not distinguish
between sigmoid (6th order) and sets of
sigmoid (5th order) surfaces, nor between
sequence boundaries, downlap surfaces of
condensed intervals.
Neither the absolute χ values, nor the
character of the χ logs are markedly different
between fore reef, reef core and lagoonal
facies (Table2, Figures 5 and 6) indicating that
there is not a strong facies control on χ values.
Furthermore, when χ values from the same
facies, but different ages are compared (Figure
7) there is no obvious overall change in χ
values from the oldest reef facies in PC
Section through to the youngest reef facies in
CB Section. Similarly, χ values in the older
lagoonal facies in PNC Section show no clear
difference from values in the younger lagoonal
facies of SGW Section.
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM,
MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of Carbonate Margin, Slope, and Basin Systems: (Publication
Release June/July 2013).
Figure 5. χ values curves for CB Section, CO Section and CC Section plotted against sketch logs of the sections and overlain with a stratigraphic interpretation based on
interpretation of cliff sketch shown in Figure 2.
Up
perM
ioce
ne
ReefC
om
ple
xPle
isto
cene
Reefc
ore
eolianites
and
red soils
Inner lagoon
Forereef
splope
Reef
crest
Massive
coral zone
Branching
coral zone
Dish
coral
zone
0
10
20
30
40
50
60
70
80
0
10
20
30
40
50
0
10
20
30
40
50
60
erosion su rface
erosion su rface
erosion su rfaceerosion su rface
downlap su rface
condensed i nterval
condensed i nterval
Section
CB
Section
COSection
CC
SB
SB
SB
DLS
DLS
Ci
Ci
Ci
Ci
sigmoid
sigm
oid
Set sigmoid
sigmoid
sigmoid
sigmoid
sigmoid
sigmoid
sigmoid
sigmoid
sigmoid
sigmoid
sigmoid
sigmoid
sigmoid?
sigmoid?
sigmoid?
sigmoid
c(m3/kg)
c(m3/kg)
c(m3/kg)
condensed i nterval
condensed
interval
erosion su rface
erosion surface
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
Available sampling resolution generally
precludes any more detailed analysis of
cyclicity in the χ values, Ellwood et al., (2008,
2010a and 2101b) arguing for a sampling
resolution of 0.25m or less, whereas here a
sampling resolution of 1m has been employed
and the sample spacing could not be regular
due to access.
Elemental data
Although a total of 50 elements are acquired
using ICP OES and ICP MS analyses,
chemostratigraphic studies typically rely upon
a smaller number of elements which are key to
a specific sequence. Here, the aim is to
determine which of the 50 elements acquired
are linked to terrigenous material and whether
those elements, or ratios of those elements,
show systematic changes within the reef
complexes. In order to identify which elements
are linked to terrigenous material, Eigen
vectors (EV), derived from principal
components analysis are plotted (Figure 8).
Plots of Eigen vector scores such as those on
Figure 8 are an effective method to understand
element – element relationships in sediments
(Pearce et al., 2005, Svendsen et al., 2007;
Ellwood et al., 2008; Pe-Piper et al., 2008,
Ratcliffe et al., 2010)). Elements that plot in
close proximity to one another are closely
associated in the sediments, therefore by
identifying groups of elements, their likely
mineralogical affinities can be postulated. The
elements plotted on Figure 8 fall into two
broad groups; those with negative EV1 scores
and those with positive EV1 scores. Elements
that plot with negative EV1 scores include
CaO and MgO and can therefore be assumed
to be associated with the carbonate minerals in
the samples. These carbonate-related elements
fall into two sub groups, those with negative
EV2 scores and those with positive EV2
scores. MgO has high positive EV2 scores and
CaO high negative scores, probably reflecting
the degree to which samples have been
dolomitized. Therefore, it can be assumed that
P2O5, MnO, Na2O, U, Cu, Mo and Co, with
plot in the same quadrant as MgO are all
elements that are associated with dolomite and
are therefore unlikely to be of use
chronostratigraphically. Similarly Ba, Ni, Sn
and Sr plot in the same quadrant as CaO and
are therefore associated with the amount of
calcite, again unlikely to provide meaningful
chronostratigraphic information from whole
rock samples.
The group of elements with high positive EV1
scores includes SiO2 and Al2O3 and is
therefore associated with siliciclastic minerals
in the sediments, which in the Llucmajor
platform must have been introduced by air fall.
Also included in this group of elements are
TiO2, Th, Zr, Cr and Nb, all of which are
typically associated with detrital input into
depositional systems (Scopelliti, et al., 2006,
Tribovillard et al, 2006, Ramkumar et al.,
2011, Ver Straeten et al., 2011). These
elements cluster around the zero EV2 axis
indicating that they are not influenced by the
amount of MgO versus CaO, i.e. they are not
affected by dolomitisation. It is this group of
elements that potentially provide a means of
chronostratigraphically significant
chemostratigraphic correlation and which are
used below to consider changes in elemental
composition through time.
Figure 9 displays a series of binary diagrams,
which provide another means to assess the
element-to-element associations in the
sediments. Figures 9a-d show that SiO2, TiO2,
K2O and Fe2O3 all have well defined linear
trends when plotted against Al2O3, indicating
that each of these elements is associated with
al-silicates. The few samples on Figure 9a that
have high SiO2 values relative to Al2O3 values
(i.e. plot off the main linear trend) may reflect
concentrations of detrital quartz grains, or
more probably reflects either biogenic or
diagenetic quartz. Although Cr and Zr plot in
the overall group of elements labeled
“terrigenous” on Figure 8, their linear
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
association with Al2O3 (and therefore with
SiO2 based on Figure 9a) is weak, implying
that there may be more than simple air fall
terrigenous material present (see Discussion).
Figure 6 shows that samples from the lagoonal
facies have higher average SiO2, Al2O3, Fe2O3
and K2O contents than reef core or fore reef
facies, this indicates that there is some degree
of facies control on the terrigenous-related
elemental data (Table 2).
Figure 6. χ values and selected major element values
in fore reef, reef and lagoonal facies. All samples from
the study have been assigned to a one of the three
main facies present (fore reef, reef core and lagoonal)
and are plotted here to demonstrate any changes in χ
values and elemental concentrations that are related
to facies.
On the scale of these reef complexes, the
composition of the terrigenous material
entering the reef complex is unlikely to have
changed laterally, therefore the facies control
likely reflects depositional sorting, i.e.
terrigenous material was preferentially ponded
in the lagoonal facies. Therefore, in order to
see how the trace element geochemistry of the
siliciclastic components change through time,
the elemental compositions of each facies has
been considered separately (Figures 7 and 10).
Changes in elemental composition
through time
Reef Core facies
The chemical logs displayed on the left of
Figure 7 are constructed from the reef core
facies in each of the study sections, the oldest
at the base (PC section), working through to
the youngest at the top (CB section). Within
each section the samples are plotted in
stratigraphic order. The chemical logs
demonstrate that from deposition of the reefs
in the PC section to deposition of reefs in the
CO section Cr values gradually increase,
reaching a maximum in the lower parts of the
CO section. Reef core facies of the CB section
have generally low Cr values, although toward
the top of the section, Cr starts to increase,
suggesting the onset of another upward
increase in Cr values. Zr/Cr values display an
overall upward decrease, with two notable
steps, one between samples from PC section
and PNC section and the other between
samples from the CO and CB sections (Figure
7).
Lagoonal facies
The chemical logs on the right of Figure 7 are
constructed from the lagoonal facies of the
PNC and SGW sections, which the Wheeler
Diagram clearly show to be of different ages.
The PNC Section samples high Cr/Nb and
Cr/Zr values compared the SGW lagoonal
samples.
Fore reef facies
The binary diagrams on Figure 9 show that the
fore reef samples from the CB section are
chemically different to those of the CC and
CO sections. The CB section fore reef samples
have higher Al2O3/TiO2 values and Ga/Rb
values than the CC and CO section fore reef
deposits. The fore reef deposits in the CC and
CO sections are almost synchronous and are
correlated using χ values in Figure 3, whereas
the fore reef sections from the CB Section are
younger than those of CC and CO Sections.
0.0
0.0
0.0
0.0
0.1
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0.3
0.4
0.5
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0.8
0.8
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0.8
0.6
0.6
0.9
1.0
1.1
1.2
1.2
1.2-0 0 0 0 0 0 0 0 0 0
0.0
0.0
0.0
0.3
0.6
0.9
1.2
1.5
0.0
0.0
0.0
0.0
0.0
0.0
0.000000
0.0
0.3
0.6
0.9
1.2
1.5
0.0
0.0
MSS Al Si Fe Ti
Lagoon
Reef
Slope
0 - 8 0 - 1.20 - 0.60 - 1.50 - 1.5
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM,
MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of Carbonate Margin, Slope, and Basin Systems: (Publication
Release June/July 2013).
Figure 7. Changes in χ values and selected elemental ratios through time. On the left, samples from reef core facies are arranged such that the oldest reef core facies (PC Section) are at the
base and youngest (CB Section) are at the top. The thick grey lines and associated letter (A-E) show approximately where the sections are on the Wheeler diagram. On the right, samples from
lagoonal facies are arranged such that the oldest (PNC Section) are beneath the younger ones from SGW section. Block lines and associated numeral (1-2) show approximately where the
sections are on the Wheeler diagram. The data are arranged in this manner to show how selected element ratios within a single facies change through time, whereas no such secular change
is seen in the χ values. Refer to Figure 2 for section locations on cliff sections.
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
Lagoonal facies
The chemical logs on the right of Figure 7 are
constructed from the lagoonal facies of the
PNC and SGW sections, which the Wheeler
Diagram clearly show to be of different ages.
The PNC Section samples high Cr/Nb and
Cr/Zr values compared the SGW lagoonal
samples.
Fore reef facies
The binary diagrams on Figure 9 show that the
fore reef samples from the CB section are
chemically different to those of the CC and
CO sections. The CB section fore reef samples
have higher Al2O3/TiO2 values and Ga/Rb
values than the CC and CO section fore reef
deposits. The fore reef deposits in the CC and
CO sections are almost synchronous and are
correlated using χ values in Figure 3, whereas
the fore reef sections from the CB Section are
younger than those of CC and CO Sections.
Figure 8. Cross plot of Eigen vector 1 and 2 scores for
all elemental acquired from all sections.DISCUSSION
Elemental Data
Although the elemental data do not provide a
means to define stratal surfaces in the reef
complexes in the manner of χ values, they do
clearly show gradual and stepped changes
through time (Figures 7 and 10). This type of
change forms the basis for chemostratigraphic
characterization, i.e. units with different
elemental compositions that are shown to be
stratigraphically significant cannot be
correlative. Therefore, reef-core facies, for
example, with different elemental
compositions cannot be time correlative,
provided the elements and element ratios used
in the characterization can be shown to be
related to changes that took place through
time, not changes that relate to facies or
diagenesis. In Figure 3, for example, the
possible correlation displayed on the left (3a),
cannot be correct since the reef core facies in
the Cap Blanc Section are chemically different
to those in the CC and PNC sections (Figure
7). The chemical logs shown on Figure 7,
however do not contradict the correct
correlation on the right of Figure 3 (3b).
The elements used to characterise temporal
changes are Cr, Zr, Al2O3, TiO2, Ga and Rb
(Figures 7 and 10). These elements are all
linked to non-carbonate, non-diagenetic
minerals and must therefore somehow reflect
changes in the types and amounts of
windblown material, including tuffaceous
debris within the sediments.. Direct
determination of changes in mineralogy
associated the chemical changes is impossible
with the available sample material. The almost
pure carbonate nature of these sediments and
the available sample volume precludes
obtaining accurate determination of clay
mineral species using XRD and it would not
be possible to carry out the heavy mineral
analyses to determine the composition of
detrital grains. It is unlikely that sufficient non
carbonate material could be identified in thin
section or using scanning electron microscopes
to provide statistically meaningful data. The
limiting factor of sample volume is a common
one in subsurface samples, where non-
destructive or minimal destruction of sample is
a prerequisite for analyses. Therefore, methods
employed here for the interpretations of the
changing elements and element ratios are in
many ways typical of dealing with “pure”
carbonates in a subsurface environment.
Application of Eigen vectors to understanding
element-to-element
-0.5
-0.4
-0.3
-0.2
-0.1-0.2 0 0.1 0.2
CaO
Sr
Ni
Sn
-0.1
0
0.1
0.2
0.3
0.4
0.5
Al2O
3
SiO2
TiO2
Fe2O
3
MnO
MgO
Na2O
K2O
P2O
5
Ba
Be
Cr
Sc
Zn
Zr
V
Co
Cu
Ga
Y
MS Nb
MoCsLREE
MREEHREE
Th
U
Eigen vector 1Calcite
Terrigenous
Dolomite
Eig
en
Vect
or
2
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM,
MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of Carbonate Margin, Slope, and Basin Systems: (Publication
Release June/July 2013).
0.05 0.10 0.15 0.200.00.0
0.3
0.6
0.9
1.2
1.5
0 1 2 3 4 5 6 7 80.0
0.3
0.6
0.9
1.2
1.5
0.0 0.1 0.2 0.3 0.4 0.5 0.60.0
0.3
0.6
0.9
1.2
1.5
0.0 0.3 0.6 0.9 1.2 1.50.0
0.3
0.6
0.9
1.2
1.5
0.0 0.1 0.2 0.3 0.4 0.50.0
0.3
0.6
0.9
1.2
1.5
0 5 10 15 20 250.0
0.3
0.6
0.9
1.2
1.5
0 5 10 15 20 250.0
0.3
0.6
0.9
1.2
1.5
0 3 6 9 12 150.0
0.3
0.6
0.9
1.2
1.5
0.0 0.2 0.40.0
0.3
0.6
0.9
1.2
1.5
Al
Al 2O 3
Al 2O 3
Al 2O 3
Al 2O 3
Al 2O 3
Al 2O 3
Al 2O 3
Cr
Cr
Th
Th
Zr
TiO2SiO2
Fe2O3
KzO
c
High SiO2, low Al2O3biogenic or diagentic quartz ?
Lagoonal facies samplesReef core facies samplesFore reef facies samples
Figure 9. Binary diagrams constructed for selected elements and χ values to help understand the element-to-element and
element-to- χ values relationships.
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
and element-to-mineral relationships has
already been discussed for the entire dataset
(Figure 8). Figure 11 shows Eigen vectors 1
and 2 derived when principal components
analysis is carried out using just the group of
elements with high positive EV1scores on
Figure 8. These non-carbonate related
elements also fall into four clearly delineated
groups:
Group 1 includes SiO2, which plots on its own
in the bottom left quadrant. When dealing with
siliciclastic sequences, SiO2 is preferentially
associated with quartz (Pearce et al. 2005,
Ratcliffe et al., 2010), which here is likely to
be in the form of fine silt-size wind-blown
grains. It is assumed that the isolated platform
nature of Llucmajor precludes coarse dust of
and that here, the dust is all fine dust defined
by Stuut et al., (2009) as fine silt (4-8microns)
and very fine silt (2-4microns).
Group 2 includes Al2O3, K2O, TiO2, Fe2O3, Ga
and Rb which plot in a tight cluster in the
bottom right quadrant and K2O, TiO2, Fe2O3
are shown in Figure 9 to have a strong positive
linear association with Al2O3. When dealing
with siliciclastic sequences, Al2O3 is typically
associated with clay minerals (Pearce et al.
2005, Ratcliffe et al., 2010). Therefore it can
be assumed that elements associated with
Al2O3 are also primarily related to clay
minerals in the sediments. The fact that SiO2
and Al2O3 have an R2 coefficient of >.95
(Figure 9) indicates that quartz is also
somehow linked to clay minerals. Typically, in
a siliciclastic system, SiO2 vs. Al2O3 binary
diagrams produce negative linear associations,
because as quartz increases in volume within
siliciclastic sediment, clay decreases, resulting
in the silt-dilution trend of Pearce et al. (2005).
However, when the quartz and clay minerals
are being introduced into a carbonate system
by the same process, which here is by aeolian
processes, both will increase in a linear fashion
as the carbonate increase or decreases, i.e.
carbonate dilution trend of Sageman et al.
(2003).
Group 3 includes Cs, Nb, Sc, Ta and Th which
plot in the upper right quadrant, i.e. have
similar EV1 scores to Group 2 elements but
similar EV2 scores to Group 3 elements.
Although this group of elements is not readily
associated with a mineral phase or group, the
EV scores and their moderate R2 coefficients
with Al2O3 (Figure 9) suggest a fine grained
phase that is not simply wind-blown
terrigenous material. With reports of biotite in
ash-beds, these elements are here interpreted
to indicate dilute, background amounts of
biotite and associated minerals that are being
blown into the depositional environment.
Group 4 includes Cr and Zr, which plot in the
upper left quadrant. Because these elements
have similar EV1 scores to SiO2, it can be
suggested that they are somehow associated
with the silt-sized material in the sediment, but
their lack of a linear association with Al2O3
(Figure 9) indicates that neither elements are
simply related to windblown clay or silt of a
terrigenous source. Zr is typically associated
with the heavy mineral zircon, which is likely
to be in the form of silt sized grains. Cr can be
associated with spinels, again likely to be
present as silt-sized grains. Both minerals are
potentially reflecting the coarser parts of dilute
tuffaceous material.
The discussions above and the element
groupings on Figure 11, therefore suggest a
grainsize control on the wind-blown material,
which in itself has been used with varying
degrees of success infer changes of
provenance and changes in paleoclimate of the
hinterland for wind-blown detritus (Sun et al.,
2002, Weltje and Prins 2003, Stuut et al.,
2002, Saukel et al., 2011). Without a grainsize
analysis of the insoluble residue, however,
little more can be gleaned from the current
dataset with regards to grainsize distributions.
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
Furthermore, it is somewhat peripheral to the
stratigraphic aims of the paper.
The changing amount of Cr on Figure 7
therefore indicates that the amount of Cr-rich
detrital grains (spinels ?) fluctuated within the
reef core facies. This could represent a change
in overall amount of wind-blown detritus.
However, the change in Zr/Cr values indicates
the relative proportion of Cr-rich grains and
Zr-rich grains changed through time. Such
changes in fluvial systems are related to
change in fluvial provenance (Armstrong-
Altrin, et al., 2004, Ratcliffe et al., 2004, 2006,
2007). It is therefore suggested that here it
represents a change in aeolian provenance.
All four elements used to differentiate fore-
reef facies on Figure 7 plot in Group 2 on
Figure 10, which is taken to indicate they are
associated with clay minerals. Therefore,
changes in the relative proportions of the
elements within the group are probably
indicating subtle changes in the clay minerals
species entering the depositional environment.
Al2O3 and Ga tend to be associated with
kaolinite and Rb with illite (Pearce et al.,
2005, Ratcliffe et al., 2010) and TiO2 can have
more mixed affinities. Therefore the high
Ga/Rb values in CB section fore reef settings
suggest that these sediments have a higher
kaolinite : illite ratio than the same facies inCC
and CO sections.
Magnetic susceptibility (χ)
χ values clearly define bounding surfaces of
sigmoids and sets of sigmoids, which have
themselves been shown to reflect sea level
fluctuations (Pomar and Ward 1994). This
observation is very useful for the identification
and correlation of surfaces within the reef
complexes, the main aim of this paper. It is
also consistent with one of the standard
interpretations of MS data, where cyclical χ
values are used as a proxy for sea-level
fluctuations (Crick et al., 1997, 2000, Ellwood
et al., 2000, da Silva and Boulvain, 2006),
Ellwood et al. (2000) argue that χ values
relate to aquatic lithogenic input, although
Hladil (2002) and Hladil et al., (2005) suggest
aeolian suspension and atmospheric dust may
contribute to χ values. In both the aquatic and
aeolian delivery model, χ values are directly
proportional to non-carbonate terrigenous
material. At first appearance, the χ values in
the isolated carbonate setting of the Llucmajor
reef complex described here is consistent with
a terrigenous control; as accommodation
decreases toward the top of a sigmoid,
carbonate production diminishes and,
assuming a relatively constant supply of
Figure 9. Binary diagrams constructed for selected elements and χ values to
help understand the element-to-element and element-to- χ values relationships.
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
background terrigenous material from air fall,
the proportion of terrigenous material will
increase, so χ values increase toward the top
of a sigmoid and drop sharply into the base of
the overlying unit. Similarly in condensed
sections, carbonate sedimentation was slow,
allowing greater relative concentration of
terrigenous material.
Figure 11. Cross plot of Eigen vector 1 and 2 scores
for elements associated with terrigenous input. These
elements are those which tightly cluster around the
EV2 axis, with positive EV1 scores on Figure 8
Despite the χ values of this study behaving as
expected in this type of setting and reflecting
base level fluctuations, the driving mechanism
is not readily apparent with the current
available data and is definitely not a simple
one that relates to the amount of terrigenous
material in the carbonates. As discussed above,
elements in the group that plots with high
positive EV1 scores on Figure 7 are associated
non-carbonate minerals. Figure 10 shows that
the major elements in this group have almost
perfect linear associations with one another,
indicating that they are present in the same
mineral phases within the sediments, which
are likely to be wind-blown clays and
feldspars. However, χ values do not display a
positive linear association with Al2O3. The
correlation coefficients displayed on Table 3
show that χ has a negative R2 value with CaO,
MgO and other elements associated with
carbonates (Figure 8) and a positive R2 value
with terrigenous-related elements. However, χ
values do not possess a correlation coefficient
(positive or negative) over 0.6 with any single
element analysed (Table 2), i.e. there is no
significant association between the detrital
proxies Zr, Rb, Al2O3 and TiO2 (Da Silva, et
al. 2012) Therefore, there is something other
than a simple terrigenous vs. carbonate control
influencing the χ values.
Table 3. Correlation coefficients (R2) for χ values and all elements acquired. Values of R
2 >0.75
(positive or negative) are considered to suggest significant association of the two variables.
LREE (light rare earths) is the sum of La, Ce, Pr, Nd,, MREE (middle rare earths) is the sum of
Sm, Eu, Gd, Tb and Dy, HREE (heavy rare earth) is the sum of Ho, Er, Tm, Yb and Lu.
Al2O3 SiO2 TiO2 Fe2O3 MnO MgO CaO Na2O K2O P2O5
0.45 0.43 0.43 0.51 -0.04 -0.16 -0.12 0.19 0.43 0.01
Ba Be Cr Sc Sr Zn Zr V Co Ni
0.17 0.5 0.35 0.48 -0.05 0.36 0.41 0.17 0.14 0.29
Cu Ga Rb Y Nb Mo Sn Cs LREE MREE
0.01 0.5 0.47 0.33 0.48 -0.04 0.27 0.45 0.24 0.44
HREE Hf Ta Th U
0.37 0.08 0.48 0.5 -0.04
Numerous other origins have been postulated
for the source of magnetic minerals that will
influence χ values. Among those, volcanic
origin (Crick et al., 1997), pedogenic origin
(Tite and Lininington, 1975), biogenic
magnetite formation (Hladil et al., 2004) and
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0 0.02-0.02-0.04-0.06 0.04 0.04 0.06
Al2O3
SiO2
TiO2
Fe2O
3
K2O
CrSc
Zr
Ta
Ga
Rb
Nb
Cs
Th
Eigen vector 1
Eig
en
vect
or
2
Group 3
Group 2
Group 4
Group 1
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
diagenesis have potential to affect study
intervals here. Although tuffs are reported
from the Llucmajor reef complexes, it is
suggested here that their influence on the χ
values is unlikely to be a primary control;
tuffaceous material has distinctive trace
element chemistry and therefore the χ values
would be expected to show a positive
relationship to some of the trace elements,
which they do not (Table 2). There is no
marked increase in χ values associated with
erosive, subaerially exposed surfaces in the
study intervals and in fore reef facies that have
not been subaerially exposed at sigmoid-tops χ
values still display distinctive cyclicity (Figure
5). Therefore, it seems unlikely that pedogenic
processes are a key control on χ values.
Diagenetic processes can both increase and
decrease susceptibility (Zegers et al., 2003,
Henshaw and Merrill, 1980, Rochette, 1987),
often as a result of the alteration of Fe-
minerals from one phase to another. The whole
rock elemental data acquired for
chemostratigraphy does not differentiate
between different valencies of Fe, nor can it
differentiate between oxide, hydroxides,
oxyhydroxides etc. Therefore, diagenesis
cannot be ruled out as a control on χ values
with the current dataset. Biogenic magnetite
would be unlikely to have a distinctive
elemental signature and also cannot be ruled
out with the current datasets.
Magnetic mineralogy and magnetic grain-size
variations can be determined by acquiring and
manipulating rock magnetic measurements
(Da Silva et al., 2012). As part of ongoing
work on understanding stratigraphic
applications in reef complexes, it is intended
that thermal demagnetization of a 3 axis
isothermal remnant magnetization (IRM),
frequency-dependent magnetic susceptibility,
low-field susceptibility, high-field
susceptibility, Ferrimagentic susceptibility and
anhysteretic remnant susceptibility data will be
gathered on a subset of samples from this
study. These variables should provide a clear
indication of the controls on the χ values ,
enabling a full interpretation of the observed
cyclicity to be proposed.
Irrespective of the ultimate control χ values in
these sequences are in some way associated
with sea level fluctuations, yet remain
independent of facies.
Conclusions Sigmoid-set and coset bounding surfaces are
defined by high χ values, enabling surfaces to
be correlated between closely spaced sections.
In this dataset the high χ values cannot be
directly linked to the elemental chemistry, or
to a single mineral phase or group of mineral
phases, but rock magnetism work is ongoing to
help better understand the observed χ values.
In the Llucmajor Platform, without close-
interval, high-resolution sampling, χ data do
not show long-term, non-cyclic variation,
which means that without the context provided
by the sea cliffs, a bounding surface in the PC
section would look very similar to one in the
CB section and therefore would be difficult to
put into a regional framework without
additional stratigraphic information.
Chemical data do not readily define surfaces,
but they do define intra-facies secular changes.
These changes in elemental composition
through time are related to variation in the
composition of background windblown debris,
including dilute volcanic ash. The changes in
chemistry seen within the reef and fore reef
facies suggest that changes in silt-sized heavy
or opaque minerals and changes the clay
mineralogy, both occurred during deposition
of the study sections. Such changes provide
the building blocks for chemostratigraphic
correlations, i.e. rock units of differing ages
have different chemical compositions.
Therefore, this study shows that elemental
chemostratigraphy can be applied in pure
carbonates where only wind-blown detritus is
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
the only source of terrigenous input, assuming
changes in the composition of the windblown
detritus.
Elemental data and χ values can both be
determined readily from well bore cuttings and
core samples, making the techniques ideally
suited to subsurface stratigraphic applications.
It is unlikely that the correlation displayed on
Figure 3b would be achieved with no further
information than elemental and χ data from
the individual sections if they were in the
subsurface. However, by gathering and
interpreting MSS and chemostratigraphic
information, a closer approximation to the
actual correlation (Figure 3a) would be
achieved than could be achieved using more
traditional subsurface correlation techniques.
Therefore, by demonstrating responses of χ
values and elemental data in the Llucmajor
Platform carbonates, this paper indicates that
the two stratigraphic methods, magnetic
susceptibility and chemostratigraphy, can be
successfully deployed in understanding
stratigraphies of pure carbonate lithologies
such as those found in detached or isolated
carbonate platforms. It also highlights that X
values here are not a simple system that can be
readily related to the bulk composition of the
sediments via elemental data.
Acknowledgements We would like to thank all of our colleagues
for help and support during preparation of this
Manuscript. Specifically, Chemostrat wish to
thank Lorna Dyer at Greenwich University for
preparing and running the ICP analysis of the
samples and for providing Emma Davies and
Ken Ratcliffe time and support to prepare this
manuscript. Luis Pomar work was done under
Spanish DGI Project CGL2009-13254. We
also gratefully acknowledge the many
comments and suggestions made by the two
reviewers, incorporation of which into the
manuscript enormously improved the final
product.
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
References
ABREU, V.S. AND HADDAD, G.A., 1998.
Glacioeustatic fluctuations: the mechanism linking stable isotope events and sequence
stratigraphy from the Early Oligocene to
Middle Miocene. In GRACIANSKY C.-P.,
HARDENBOL, J., JACQUIN, T. AND VAIL, P.R., (eds) Mesozoic and Cenozoic sequence
stratigraphy of European basins: p. 245-260.
Tulsa: Society for Sedimentary Geology, SP No. 60.
ALGEO, T.J., SCHWARK, L., AND HOWER, J.C.
2004. High-resolution geochemistry and
sequence stratigraphy of the Hushpuckney Shale (Swope Formation, eastern Kansas):
implications for climato-environmental
dynamics of the Late Pennsylvanian Midcontinent Seaway: Chemical Geology, v.
206, p. 259–288.
ARMSTRONG, A.J.S., LEE, Y.I., VERMA, S.P.,
AND RAMASAMY, S. 2004. Geochemistry of
sandstones from the upper Miocene
Kudankulam Formation, southern India: Implications for provenance, weathering, and
tectonic setting: Journal of Sedimentary
Research, v. 74, p.285-297.
CASTILLO, S. MORENO, T., QUEROLA, X.
ALASTUEY, A., CUEVAS, E., HERRMANN, L. MOUNKAILA, M. AND GIBBONSD, W. 2008.
Trace element variation in size-fractionated
African desert dusts: Journal of Arid
Environments, v. 71, P. 1034-1045.
CRICK, R.E., ELLWOOD, B.B., HASSANI, A.,
FEIST, R. AND HLADIL, J. 1997. Magnetosusceptibility event and
cyclostratigraphy (MSEC) of the Eifelian-
Givetian GSSP and associated boundary sequences in north Africa and Europe:
Episodes, v. 20, p. 167-175.
CRICK, R.E., ELLWOOD, B.B., EL HASSANI, A.,
FEIST, R. 2000. Proposed magnetostratigraphy
susceptibility magnetostratotype for the
Eifelian–Givetian GSSP (Anti-Atlas, Morocco): Episodes v. 23, p. 93–101.
DA SILVA, A.C. AND BOULVAIN, F. 2006. Upper Devonian carbonate platform
correlations and sea level variations recorded in magnetic susceptibility. Palaeogeography,
Palaeoclimatology, Palaeoecology, v. 240, p.
373-388.
DA SILVA, A.C., POTMA, K., WEISSENBERGER,
J.A.W., WHALEN, M.T., HUMBLET, C.M. AND
BOULVAIN, F. 2009. Magnetic susceptibility
evolution and sedimentary environments on
carbonate platform sediments and atolls,
comparison of the Frasnian from Belgium and Alberta, Canada: Sedimentary Geology, v.
214, p. 3-18.
DA SILVA, A.C., DEKKERS, M.J., MABILLE, C.
AND BOULVAIN, F. 2012. Magnetic
susceptibility and its relationship with palaeoenvironments, diagenesis and
remagnetisation: examples from the Devonian
carbonmates of Belgium: Studia Geophysica et
Geodaetica, v. 56, p. 677-704.
ELLWOOD, B.B., CHRZANOWSKI, T.H.,
HROUDA, F., LONG, G.J., AND BUHL, M.L. 1988. Siderite formation in anoxic deep-sea
sediments: a synergetic bacterially controlled
process with important implications in
paleomagnetism Geology: v. 16, p. 980-982.
ELLWOOD, B.B., BURKART, B., RAJESHWAR,
K., DARWIN, R.L., NEELY, R.A., MCCALL, A.B., LONG, G.J., BUHL, M.L., AND HICKCOX,
C.W. 1989. Are the iron carbonate minerals,
ankerite, and ferroan dolomite, like siderite, important in paleomagnetism?: Journal of
Geophysical Research, v. 94, p. 7321-7331.
ELLWOOD, B.B., CRICK, R.R., EL HASSANI,
A., BENOIST, S.L.R.H. AND YOUNG, R.H.
2000. The magnetosusceptibility event and
cyclostratigraphy (MSEC) method applied to marine rocks: detrital input versus carbonate
productivity: Geology, v. 28, p. 1134–1138.
ELLWOOD, B.B., CRICK, R.E., FERNANDEZ,
J.L.G., SOTO, F.M., TRUYOLS-MASSONI, M.,
HASSANI, A. AND KOVAS, E.J. 2001. Global correlation using magnetic susceptibility data
from Lower Devonian rocks: Geology, v. 29,
p.583-586.
ELLWOOD, B.B., TOMKIN, J.H., RATCLIFFE,
K.T., WRIGHT, A.M., AND KAFAFY, A.M.
2008. Magnetic Susceptibility and
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
Geochemistry for the Cenomanian/Turonian Boundary GSSP with Correlation to Time
Equivalent Core: Palaeogeography,
Palaeoclimatology, Palaeoecology, v. 251, p. 1–22.
ELLWOOD, B.B., KAFAFY, A.M., KASSAB, A., TOMKIN, J.H., ABDELDAYEM, A., OBAIDALLA,
N., RANDALL, K.W., AND THOMPSON, D.E.
2010a. Magnetostratigraphy susceptibility
used for high resolution correlation among Paleocene-Eocene boundary sequences in
Egypt, Spain and the USA: in RATCLIFFE,
K.T. AND ZAITLIN B.A. (eds.) Application of Modern Stratigraphic Techniques: Theory and
Case Histories: SEPM SP PUB no 94, p. 155-
167.
ELLWOOD, B.B., KAFAFY, A.M., KASSAB, A.,
ABDELDAYEM, A., OBAIDALLA, N., HOWE,
R.W., AND SIKORA, P. 2010b. Magnetostratigraphy susceptibility used for
high resolution correlation among Santonian
(Upper Cretaceous) marine sedimentary sequences in the U.S. Western Interior Seaway
and the Western Sinai Peninsula, Egypt: in
RATCLIFFE, K.T. AND ZAITLIN B.A. (eds.)
Application of Modern Stratigraphic Techniques: Theory and Case Histories:
SEPM SP PUB no 94, p167-183.
HENSHAW, P.C. AND MERRILL, R.T. 1980.
Magnetic and chemical changes in marine
sediments: Reviews of Geophysics and Space Physics, v. 18, p. 483-504.
HILDRED, G.V., RATCLIFFE, K.T., WRIGHT,
A.M., ZAITLIN, B.A., AND WRAY, D.S. 2010. Chemostratigraphic applications to low-
accommodation fluvial incised-valley settings;
an example from the Lower Mannville Formation of Alberta, Canada: Journal of
Sedimentary Research, v. 80, p. 1032-1045.
HLADIL, J. 2002. Geophysical records of
dispersed weathering products on the Frasnian
carbonate platform and early Famennian
ramps in Moravia, Czech Republic: proxies for eustasy and palaeoclimate: Palaeogeography,
Palaeoclimatology, Palaeoecology, V. 181, p.
213–250.
HLADIL, J., CAREW, J.L., MYLROIE, J.E.,
PRUNER, P,. KOHOUT, T., JELL, L.S., LACKA,
B. AND LANGROVA, A. 2004. Anomalous magnetic susceptibility values and traces of
subsurface microbial activity in carbonate
banks on San Salvador Island, Bahamas: Facies, v. 50, p161-182.
HLADIL, J., GERSI, M., STRNAD, L., FRANA, N. C., LANGROVA, A. AND SPISIAK, J. 2005.
Stratigraphic variation of complex impurities
in platform limestones and possible
significance of atmospheric dust : a study with emphasis on gamma-ray spectrometry and
magnetic susceptibility outcrop logging
(Eifelian-Frasnian, Moravia, Czech Republic): International Journal of Earth Sciences, v. 95,
p. 703-723.
JARVIS, I., AND JARVIS, K.E. 1995. Plasma
spectrometry in earth sciences: techniques,
applications and future trends: in Jarvis, I.,
and Jarvis, K.E., (eds.) Plasma Spectrometry in Earth Sciences: Chemical Geology, v. 95, p.
1–33.
NAGATA, T. 1961. Rock Magnetism: Revised
Edition: Tokyo, Maruzen Company Ltd.
PEARCE, T.J., WRAY, D.S., RATCLIFFE, K.T.,
WRIGHT, D.K. AND MOSCARELLO, A. (2005). Chemostratigraphy of the Upper
Carboniferous Schooner Formation, southern
North Sea: in Collinson, J.D., Evans, D.J., Holliday, D.W. and Jones N.S. (eds) Yorkshire
Geological Society, Occasional Publications
series, v.7, p.147–64.
PE-PIPER, G., TRIANTAFYLLIDIS, S., AND
PIPER, D.J.W. 2008. Geochemical
identification of clastic sediment provenance from known sources of similar geology: the
Cretaceous Scotian Basin, Canada: Journal of
Sedimentary Research, v. 78, p. 595–607.
POMAR, L. 1991. Reef geometries, erosion
surfaces and high frequency sea-level changes, Upper Miocene Reef Complex, Mallorca,
Spain: Sedimentology, v.38, p.243-269.
POMAR, L. 1993. High-resolution sequence
stratigraphy in prograding carbonates:
Application to seismic interpretation: in
LOUCKS, R. AND SARG R. (eds) Recent Advances and applications of Carbonate
Sequence Stratigraphy: Tulsa, American
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
Association of Geologists, Memoir 57, p.389-407.
POMAR, L. AND WARD W.C. 1994. Response of late Miocene Mediterranean reef platform to
high-frequency eustasy: Geology, v. 22, p.
131-134.
POMAR, L. AND WARD, W.C. 1995. Sea-level
changes, carbonate production and platform
architecture: The Llucmajor Platform, Mallorca, Spain: in HAQ, B.U. (ed.) Sequence
Stratigraphy and Depositional Response to
Eustatic, Tectonic and climate Forcing: Kluwer Academic Publishers, p. 87-112.
POMAR, L. AND WARD, W.C. 1999. Reservoir-scale Heterogeneity in Depositional package
and Diagenetic Patterns on a Reef-Rimmed
Platform, Upper Miocene, Mallorca, Spain:
American Association of Petroleum Geologists Bulletin, v. 83, p. 1759-1773.
POMAR, L., WARD, W.C. AND GREEN, D.G. 1996. Upper Miocene Reef Complex of the
Llucmajor area, Mallorca, Spain: in E.
FRANSEEN, M. ESTEBAN, W.C. WARD AND
J.M. ROUCHY (eds) Models for Carbonate
Stratigraphy from Miocene Reef Complexes of
the Mediterranean regions: Society of
Economic Paleontologists and Mineralogists: Concepts in Sedimentology and Paleontology
Series, n. 5, pp. 191-225.
RAMKUMAR, M., STÜBEN, D. AND BERNER, Z.
2011. Barremian–Danian chemostratigraphic
sequences of the Cauvery Basin, India: Implications on scales of stratigraphic
correlation: Gondwana Research, v. 19, p.
291-309.
RATCLIFFE, K.T., WRIGHT, A.M.,
HALLSWORTH, C., MORTON, A., ZAITLIN,
B.A., POTOCKI, D. AND WRAY, D.S. 2004. An example of alternative correlation techniques
in a low accommodation setting, non-marine,
hydrocarbon system: the (Lower Cretaceous) Manville Basal Quartz succession of southern
Alberta: American Association of Petroleum
Geologists Bulletin, v. 88, p. 1419-1432.
RATCLIFFE, K.T., HUGHES, A.D., LAWTON,
D.E., WRAY, D.S., BESSA, F., PEARCE, T.J.
AND MARTIN. J. 2006. A regional
chemostratigraphically-defined correlation framework for the late Triassic TAG-I in
Blocks 402 and 405a, Algeria: Petroleum
Geoscience, v. 12, p. 3–12.
RATCLIFFE, K.T., MORTON, A., RITCEY, D.,
AND EVENCHICK, C.E. 2007. Whole rock geochemistry and heavy mineral analysis as
exploration tools in the Bowser and Sustut
Basins, British Colombia, Canada: Journal of
Canadian Petroleum Geology, v.55, p.320–37.
RATCLIFFE, K.T., WRIGHT, A.M.,
MONTGOMERY, P., PALFREY, A., VONK, A., VERMEULEN, J. AND BARRETT, M. 2010.
Application of chemostratigraphy to the
Mungaroo Formation, the Gorgon Field, offshore Northwest Australia: APPEA Journal
2010: 50th Anniversary Issue p. 371–385.
RATCLIFFE, K.T. AND ZAITLIN B.A. (eds.), 2010. Application of Modern Stratigraphic
Techniques: Theory and Case Histories:
SEPM Special Publication no. 94. 241pp.
ROCHETTE, P. 1987. Metamorphic control on
the magnetic mineralogy of black shales in the Swiss Alps: toward the use of “magnetic
isogrades”: Earth and PLanetary Sciences
Letters, v. 84, p. 446-456.
ROWE, H., HUGHES, N. AND ROBINSON, K.
2012. The quantification and application of
handheld energy-dispersive x-ray fluorescence (ED-XRF) in mudrock chemostratigraphy and
geochemistry: Chemical Geology, v. 324 p.
122-131.
SAUKEL, C., LAMY, F., STUUT, J-B.W.,
TIEDEMANN, R. AND VOGT, C. 2011.
Distribution and provenance of wind-blown SE Pacific surface sediments: Marine
Geology, v. 280, p. 130-142.
SAGEMAN, B.B., MURPHY, A.E., WERNE J.P.,
VER STRAETEN, C.A., HOLLANDER, D.J.,
LYONS T.W. 2003. A tale of shales: the relative roles of production, decomposition,
and dilution in the accumulation of organic-
rich strata, Middle–Upper Devonian,
Appalachian basin: Chemical Geology, v. 195, p. 229-273.
SCOPELLITI, G., BELLANCA, A, COCCIONI, R., LUCIANI, V., NERI, R., BAIDIN, F., CHIARI, M.,
MAGNETIC SUSCEPTIBILITY (Χ STRATIGRAPHY AND CHEMOSTRATIGRAPHY APPLIED TO AN ISOLATED
CARBONATE PLATFORM REEF COMPLEX; LLUCMAJOR PLATFORM, MALLORCA
Accepted for Publication: SEPM Special Publication dedicated to the Deposits, Architecture and Controls of
Carbonate Margin, Slope, and Basin Systems: (Publication Release June/July 2013).
AND MARUCCI, M. 2006. High-resolution geochemical and biotic records of the Tethyan
‘Bonarelli Level’ (OAE2, latest Cenomanian)
from the Calabianca–Guidaloca composite section, northwestern Sicily, Italy:
Palaeogeography, Palaeoclimatology,
Palaeoecology, v. 208, p. 293– 317.
SOUA, M. 2010. Productivity and bottom water
redox conditions at the Cenomanian-Turonian
Oceanic Anoxic Event in the southern Tethyan margin, Tunisia: Revue Méditerranéenne de
l’Environnement, v. 4, p. 653-664.
STAGE, M. 2001. Magnetic susceptibility as a
carrier of climatic signal in chalk: Earth and
Planetary Science Letters, v. 188, p 17-27.
STUUT, J-B. W., PRINS, M.A., SCHEIDER, R.R.
WELTJE, G.J. JANSEN, J.H.F. AND POSTMA, G.
2002. A 300-kyr record of aridity and wind strength in southwestern Africa: inferences
from grain-size distributions of sediments on
Walvis Ridge, SE Atlantic: Marine Geology, v. 180, p. 221-233.
STUUT, J-B, SMALLEY, I. AND O’HARA, K. 2009. Aeolian dust in Europe: African sources
and European deposits, V. 1, P. 234–245.
SUN, Y., LU, H. AND AN, Z. 2002. Grain size of loess, palaeosol and Red Clay deposits on the
Chinese Loess PLateau: Significance for
understanding pedogenic alteration and palaeomonsoon evolution: Palaeogeography,
Palaeoclimatology, Palaeoecology, v. 241, p.
129-138.
SVENDSEN, J., FRIIS, H., STOLLHOFEN, H.,
AND HARTLEY, N. 2007. Facies discrimination
in a mixed fluvio-eolian setting using elemental whole-rock geochemistry:
applications for reservoir characterization:
Journal of Sedimentary Research, v. 77, p. 23–33.
SWARTZENDRUBER, L.J., 1992. Properties, units and constants in magnetism: Journal of
Magnetic Materials, v. 100, p. 573–575.
TITE, M.S. AND LININGTON, R.E. 1975. Effect
of climate on the magnetic susceptibility of soils: Nature, v. 256, p 565-566.
TRIBOVILLARD, N., ALGEO, T.J., LYONS, T., AND RIBOULLEAU, A. 2006. Trace metals as
paleoredox and paleoproductivity proxies: An
update: Chemical Geology, v. 232, p. 12–32.
VER STRAETEN, C.A., BRETT, C.E. AND
SAGEMAN, B.B. 2011. Mudrock sequence stratigraphy: A multi-proxy (sedimentological,
paleobiological and geochemical) approach,
Devonian Appalachian Basin:
Palaeogeography, Palaeoclimatology, Palaeoecology, v. 304, p. 54-73.
WANG, X., HUANG, N. DONG, Z. AND ZHANG, C. 2010. Mineral and trace element analysis in
dust fall collected in the Hexi Corridor and its
significance as an indicator of environmental changes: Environmental Earth Sciences, v. 60,
p. 1-10.
WELTJE G. AND PRINS, M.A. 2003. Muddled or mixed ? Inferring plaeoclimate from size
distributions of deep sea clastics: Sedimentary
Geology, v. 162, p. 39-62.
WRAY, D.S. AND GALE, A.S. 2006. The
palaeoenvironment and stratigraphy of Late Cretaceous Chalks: Proceedings of the
Geologists' Association, v. 117 , p. 145-162.
WRIGHT, A.M., RATCLIFFE, K.T., ZAITLIN, B.A. AND WRAY, D.S. 2010. The application
of chemostratigraphic techniques to
distinguish compound incised valleys in low-accommodation incised-valley systems in a
foreland-basin setting: an example from the
Lower Cretaceous Manville Group and Basal Colorado Sandstone (Colorado Group),
Western Canadian Sedimentary Basin: in
RATCLIFFE, K.T. AND ZAITLIN B.A. (eds.)
Application of Modern Stratigraphic Techniques: Theory and Case Histories SEPM
Special Publication no. 94, p. 93-109.
ZEGERS, T.E., DEKKERS, M.J. AND BAILY, S. 2003. Late Carboniferous to Permian
magnetization of Devonian limestones in the
Ardennes: Role of Temperature, fluids and
deformation: Journal of Geophysical Research, v. 108, p. 1-19