Brittle faulting in
the southern
contact zone of the
Karkonosze granite
g
near Karpacz
p
Krzysztof Gaidzik, Jerzy Żaba
Department of Fundamental Geology
Faculty of Earth Sciences
University of Silesia
Aim
- Reconstruct p
paleostress tensor responsible
p
for development
p
definite brittle faults
populations in the area of Karpacz
Labo
oratory
Field
M th d l d
Methodolody
-Collect fault
fault--slip data;
-Define direction and sense of movement along fault planes;
-Find out relative relations between fault populations
populations.
-Angelier and Hoeppener diagrams;
-Classify heterogenous faultfault-slip data into homogenous populations;
-Apply methods: right dihedra method, inverse method;
-Present results on diagrams and maps.
Geological sketch map of the Karkonosze granite and its metamorphic cover (after Aleksandrowski & Mazur, 2002).
Study
St
d area - southern
th
contact
t t zone off the
th Karkonosze
K k
granite
it in
i the
th area off
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
=
Two
T
compressional
quadrants ((σ1)
q
Two tensional
quadrants
d t ((σ3)
Faults from the area of Karpacz
A
Angelier
li di
diagram
Hoeppener diagram
Datasets: 50
Mostly: strike-slip faults (dextral), oblique faults with dominant strike-slip
component
Lower hemisphere
Fault planes:
-dominant direction
(strike) – NE-SW;
-mostly steep and very
steep dip angle (strike(strike
slip faults).
Slip lineations:
-dominant dip direction
– SW;
-mostly low and very
low dip angle (strikeslip faults)
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
Tectonic striae on mesofaults surfaces
90
80
Sinistral
Tectonic sttriae (Dip a
T
angle)
70
Dextral
Normal-dextral
1
60
50
Normal-sinistral
Reverse-dextral
40
Reverse-sinistral
Reverse
30
Normal
Horizontal
3
20
4
10
5
2
0
0
10
20
30
40
50
60
Mesofaults (Dip angle)
70
80
90
Unknown
First („normal”) population
Datasets: 7
Hoeppener diagram
Angelier diagram
First („normal”) population
Planes:
-dominant NNE-SSW,
NE-SW;
-steep (50-70º).
Slip lineations:
-dominant NW;
-steep (50-70º).
First („normal”) population
Normal regime
The Right Dihedra method
σ1 – 77/68
σ2 – 212/16
σ3 – 307/15
The Inverse method
Predominant (second) population
Datasets: 25
Hoeppener diagram
Angelier diagram
Predominant (second) population
Rose diagram
Planes:
-dominant NE-SW;;
-Steep and very steep
(60-90º).
Rose diagram
Slip lineations:
-dominant towards
SW;;
-low and very low
angles (0-20º).
Predominant (second) population
Strike-slip regime
Right Dihedra method
σ1 – 38/11
σ2 – 256/76
σ3 – 130/08
Inverse method
Third population
Datasets: 5
Hoeppener diagram
Angelier diagram
Third population
Planes:
-dominant NE-SW;
-intermediate
intermediate angles to
steep.
Slip lineations:
-dominant towards
SW;
-intermediate angles
(30-50º).
Third population
Strike-slip regime
Normal regime
The Right Dihedra method
σ1 – 192/34
σ2 – 356/55
σ3 – 97/08
The Inverse method
Fourth („Reverse”) population
Datasets: 2
Hoeppener diagram
Angelier diagram
Fourth („Reverse”) population
Planes:
-dominant W-E, NWSE;
-intermediate angles.
Slip lineations:
-dominant SW;
-low angles (20-30º).
Fourth („Reverse”) population
Reverse regime
σ1 – 37/16
The Right Dihedra method
σ2 – 130/13
σ3 – 259/69
Fifth („strike-slip”) population
Datasets: 5
Hoeppener diagram
Angelier diagram
Fifth („strike-slip”) population
Planes:
-dominant NW-SE;
-very
very steep (80
(80-90º).
90º)
Slip lineations:
-dominant SE;
-low
low angles (10
(10-20º).
20º)
Fifth („strike-slip”) population
Strike-slip regime
The Right Dihedra method
σ1 – 294/06
σ2 – 69/82
σ3 – 204/06
The Inverse method
Compressional
(white) and
tensional (black)
sectors for every
fault from the
area of Karpacz
on the basis of
geological
sketch
k t h off the
th
studied area.
Karkonosze granite
Gneiss
Mica schist
Lower hemisphere
Conclusions
- Strike
Strike--slip faults are predominant;
- Fault planes – strike NENE-SW, steep and very steep;
- Slip lineations – mostly towards SW,
SW low and very low
angle;
- 5 homogenous fault populations;
- All possible regimes (strike
(strike--slip, normal –
gravitational,
it ti
l reverse)) were iinvolved;
l d
- Normal population is older than predominant;
- Predominant population was developed in strike
strike--slip
regime (σ
(σ1 towards NENE-SW,
SW σ3 towards NWNW-SE);
- Except one example σ1 more or less towards NENE-SW;
- Except one example σ3 more or less towards NWNW-SE.
σ1 – red
σ2 – black
σ3 – blue