Brittle faulting in Brittle faulting in Brittle faulting in Brittle faulting in the southern the southern the southern the southern

contact zone of the contact zone of the Karkonosze granite Karkonosze granite gg

near Karpacznear Karpaczpp

Krzysztof Gaidzik, Jerzy ŻabaKrzysztof Gaidzik, Jerzy ŻabaDepartment of Fundamental GeologyDepartment of Fundamental GeologyDepartment of Fundamental GeologyDepartment of Fundamental Geology

Faculty of Earth SciencesFaculty of Earth SciencesUniversity of SilesiaUniversity of Silesia

AimAim-- Reconstruct paleostress tensor responsible for development definite brittle faults Reconstruct paleostress tensor responsible for development definite brittle faults p p pp p ppopulations in the area of Karpaczpopulations in the area of Karpacz

M th d l dM th d l d

Collect faultCollect fault slip data;slip data;

MethodolodyMethodolody

--Collect faultCollect fault--slip data;slip data;

--Define direction and sense of movement along fault planes;Define direction and sense of movement along fault planes;

--Find out relative relations between fault populationsFind out relative relations between fault populations

Fiel

dFi

eld

Find out relative relations between fault populations.Find out relative relations between fault populations.

--Angelier and Hoeppener diagrams;Angelier and Hoeppener diagrams;

--Classify heterogenous faultClassify heterogenous fault--slip data into homogenous populations;slip data into homogenous populations;

orat

ory

orat

ory

--Apply methods: right dihedra method, inverse method;Apply methods: right dihedra method, inverse method;

--Present results on diagrams and maps.Present results on diagrams and maps.Labo

Labo

Geological sketch map of the Karkonosze granite and its metamorphic cover (after Aleksandrowski & Mazur, 2002).

St d th t t f th K k it i th fStudy area - southern contact zone of the Karkonosze granite in the area of Karpacz: Sowia Valley, Malina Valley, Łomniczka Valley, Księża Mt., Kozi Ridge.

The right dihedra (P/T quadrant) method - principles

Fault plane

+N – plane perpendicular to the

+slip lineation on the fault

T=

Two compressional quadrants (σ1)q ( 1)

Two tensional d t ( )quadrants (σ3)

Faults from the area of Karpacz

A li di Hoeppener diagramAngelier diagram Hoeppener diagram

Datasets: 50

Lower hemisphere

Mostly: strike-slip faults (dextral), oblique faults with dominant strike-slip component

Fault planes:

-dominant direction (strike) – NE-SW;

-mostly steep and very steep dip angle (strikesteep dip angle (strike-slip faults).

Slip lineations:

-dominant dip direction – SW;

-mostly low and very low dip angle (strike-slip faults)slip faults).

Fault planes with slip lineation, steps - examples

Karkonosze granite –Kozi Ridge

Metamorphic cover –Sowia Valley

Karkonosze granite –Sowia Valley

Metamorphic cover –Sowia Valley

Karkonosze granite – Sowia Valley

90

Tectonic striae on mesofaults surfaces

80

90

60

70

angl

e)

SinistralDextralNormal-dextral

1

40

50

tria

e (D

ip a

Normal-sinistralReverse-dextralReverse-sinistral

30

40

Tect

onic

st

ReverseNormalHorizontal3

10

20

T HorizontalUnknown

354

00 10 20 30 40 50 60 70 80 90

2

Mesofaults (Dip angle)

First („normal”) population

Datasets: 7

Hoeppener diagram

Angelier diagram

First („normal”) populationPlanes:Planes:

-dominant NNE-SSW, NE-SW;

-steep (50-70º).

Slip lineations:

-dominant NW;

-steep (50-70º).

First („normal”) population

Normal regimeThe Right Dihedra method

σ1 – 77/68

Normal regime

The Inverse method

σ2 – 212/16

σ3 – 307/15

Predominant (second) population

Datasets: 25

Hoeppener diagramHoeppener diagram

Angelier diagram

Predominant (second) population

Rose diagramPlanes:

-dominant NE-SW;;

-Steep and very steep (60-90º).

Rose diagram

Slip lineations:Slip lineations:

-dominant towards SW;;

-low and very low angles (0-20º).

Predominant (second) population

Strike-slip regime

Right Dihedra methodσ1 – 38/11

σ2 – 256/76

Inverse method

σ2 256/76

σ3 – 130/08

Third population

Datasets: 5

Hoeppener diagram

Angelier diagram

Planes:

Third populationPlanes:

-dominant NE-SW;

intermediate angles to-intermediate angles to steep.

Slip lineations:

-dominant towards SW;

-intermediate angles (30-50º).

Third population

Strike-slip regime

Normal regime

The Right Dihedra methodσ1 – 192/34

The Inverse method

σ2 – 356/55

σ3 – 97/08

Fourth („Reverse”) population

Datasets: 2

Hoeppener diagram

Angelier diagram

Planes:

Fourth („Reverse”) populationPlanes:

-dominant W-E, NW-SE;

-intermediate angles.

Slip lineations:

-dominant SW;

-low angles (20-30º).

Fourth („Reverse”) population

Reverse regime

σ1 – 37/16

Reverse regime

The Right Dihedra method σ2 – 130/13

σ3 – 259/69

Fifth („strike-slip”) population

Datasets: 5

Hoeppener diagram

Angelier diagram

Planes:

Fifth („strike-slip”) populationPlanes:

-dominant NW-SE;

very steep (80 90º)-very steep (80-90º).

Slip lineations:Slip lineations:

-dominant SE;

low angles (10 20º)-low angles (10-20º).

Fifth („strike-slip”) population

Strike-slip regime

The Right Dihedra methodσ1 – 294/06

The Inverse method

σ2 – 69/82

σ3 – 204/06

Compressional (white) and tensional (black)tensional (black) sectors for every fault from the area of Karpaczarea of Karpacz on the basis of geological k t h f thsketch of the

studied area.

Karkonosze granite

Gneiss

Mica schistLower hemisphere

ConclusionsConclusions-- StrikeStrike--slip faults are predominant;slip faults are predominant;StrikeStrike slip faults are predominant;slip faults are predominant;-- Fault planes Fault planes –– strike NEstrike NE--SW, steep and very steep;SW, steep and very steep;

Slip lineationsSlip lineations mostly towards SW low and very lowmostly towards SW low and very low-- Slip lineations Slip lineations –– mostly towards SW, low and very low mostly towards SW, low and very low angle;angle;

5 homogenous fault populations;5 homogenous fault populations;-- All possible regimes (strikeAll possible regimes (strike--slip, normal slip, normal ––

it ti l ) i l dit ti l ) i l d

-- 5 homogenous fault populations;5 homogenous fault populations;

gravitational, reverse) were involved;gravitational, reverse) were involved;-- Normal population is older than predominant;Normal population is older than predominant;

-- Predominant population was developed in strikePredominant population was developed in strike--slip slip regime (regime (σσ11 towards NEtowards NE--SWSW σσ33 towards NWtowards NW--SE);SE);regime (regime (σσ11 towards NEtowards NE SW, SW, σσ33 towards NWtowards NW SE);SE);-- Except one example Except one example σσ11 more or less towards NEmore or less towards NE--SW;SW;-- Except one example Except one example σσ33 more or less towards NWmore or less towards NW--SE.SE.

σ1 – red

σ2 – black

σ3 – blue