Abstract ........................................................ I
Zusammenfassung ............................................... III
Contents ........................................................ V
List of figures ................................................ VI
List of tables ................................................ VII
1. Introduction ................................................ 1
2. Frameworks of deformation, scaling relations, dependence
on parameter influence ...................................... 4
3. The Methods ................................................. 6
3.1. Geostatistics .......................................... 6
3.2. Analogue modelling technique, advantages and limits .... 7
4. Geological Setting -The Central Andean plateau .............. 9
5. Orogen-wide patterns of strain accumulation - the Andean
case ....................................................... 12
5.1. Introduction .......................................... 12
5.2. Geological setting .................................... 12
5.3. Data preparation ...................................... 14
5.4. Statistics ............................................ 15
5.5. Results ............................................... 23
5.6. Conclusions ........................................... 27
6. The effect of mechanical heterogeneity on diversification
of deformation patterns - a modelling study with granular
media ...................................................... 28
6.1. Introduction .......................................... 28
6.2. Experimental design ................................... 29
6.3. Experimental results .................................. 30
6.4. Parameter control ..................................... 32
6.5. PIV monitoring of plateau-style settings .............. 35
6.6. Discussion ............................................ 38
6.7. Application to the Central Andean plateau ............. 41
6.8. Conclusions ........................................... 43
7. The effect of mechanical heterogeneity on plateau
initiation - a modelling study with viscous-brittle
media ...................................................... 44
7.1. Introduction .......................................... 44
7.2. Experimental design ................................... 45
7.3. Experimental results .................................. 49
7.4. Parameter effect ...................................... 53
7.5. Comparison of three experiments with
plateau-initiation .................................... 55
7.6. Discussion ............................................ 59
7.7. Conclusions ........................................... 62
8. Additional analogue data ................................... 64
9. Discussion, Conclusions and Outlook ........................ 71
10. References ................................................. 83
Appendix A-1, Deformation Database .............................. 1
Appendix A-2, Deformation distribution in 1 Ma steps ........... 17
Appendix A-3, Variogram surfaces for deformation activity in
1 Ma steps ....................................... 24
Appendix A-4, Sensitivity analysis ............................. 31
Appendix B-1, Description of granular experiments .............. 36
Appendix B-2, Set-up Sketches (granular experiments) ........... 42
Appendix B-3, Photographs of analogue devices .................. 51
Appendix B-4, Material parameters for vise experiments ......... 53
Appendix B-5, Material mixtures for vise experiments ........... 55
Acknowledgments ................................................ 59
CV ............................................................. 61
List of Figures
Figure 3.1: Formula semi-variogram ............................ 6
Figure 3.2: Definition of distance h between two
geographical locations ............................ 6
Figure 3.3: Sample variogram .................................. 7
Figure 4.1: Topographic map of the Central Andean plateau ..... 9
Figure 4.2: Schematic cross section through the Central
Andean plateau ................................... 10
Figure 5.1: Polygons and point grid of the study area ........ 13
Figure 5.2: Frequency plots .................................. 14
Figure 5.3: Frequency plots divided into structural units .... 17
Figure 5.4a: Distribution of mean shortening rates ............ 18
Figure 5.4b: Distribution of duration of deformation .......... 18
Figure 5.5: Indicator variogram surfaces for deformation
activity ......................................... 19
Figure 5.6: Variograms for deformation activit ............... 21
Figure 5.7: Kriging maps ..................................... 22
Figure 5.8: Variogram surfaces for shortening rates .......... 24
Figure 5.9: Summary of deformation stages .................... 25
Figure 6.1: Resulting deformation patterns ................... 33
Figure 6.2: Plateau-style vs. wedge-like deformation ......... 34
Figure 6.3: PIV strain image of experimental surface ......... 35
Figure 6.4a: PIV time series of plateau setting without
erosion .......................................... 36
Figure 6.4b: Finite and restored cross section of plateau
setting without erosion .......................... 36
Figure 6.5a: PIV time series of plateau setting with
erosion .......................................... 37
Figure 6.5b: Finite and restored cross section of plateau
setting with erosion ............................. 37
Figure 6.6: Topographic map of the Central Andean plateau .... 41
Figure 6.7: Profile at 21°S (Central Andes) and timing of
deformation ...................................... 42
Figure 7.1: Stages of plateau initiation and plateau
formation ........................................ 44
Figure 7.2: Topographic map of the Central Andean plateau
with basin locations ............................. 45
Figure 7.3: Experimental set-up with analogue and natural
dimensions ....................................... 46
Figure 7.4: Strength envelopes of vise and weak
lithosphere ...................................... 47
Figure 7.5: Sketches of finite patterns of all experiments ... 50
Figure 7.6: Topographic profiles through experimental
settings ......................................... 51
Figure 7.7: Structural evolution of thrust/anticline
features ......................................... 53
Figure 7.8: Principal stress trajectories cross-shaped vs.
phi pattern ...................................... 54
Figure 7.9a: PIV strain image of finite experimental surface
(Exp. 4) ......................................... 56
Figure 7.9b: PIV images of strain evolution (Exp. 4) .......... 56
Figure 7.10: PIV time series for three profiles for each
plateau-initiation setting ....................... 57
Figure 7.11a: Topographic profiles overtime (Exp. 4) ........... 58
Figure 7.11b: Topographic profiles over time (Exp. 5) .......... 58
Figure 7.12: Finite crustal thicknesses ....................... 60
Figure 8.1a: Real finite fault pattern ........................ 64
Figure 8.1b: Incremental velocity field of finite surface
(Exp. 4) ......................................... 64
Figure 8.2: Incremental velocity field of finite surface
(Exp. 6) ......................................... 64
Figure 8.3: Comparison of data resolution 1
(incremental vector displacement) ................ 66
Figure 8.4: Comparison of data resolution 2
(incremental vector displacement) ................ 67
Figure 8.5: PIV strain image and location of strain
profiles ......................................... 68
Figure 8.6: PIV time series with frequent changes in strain
accumulation ..................................... 68
Figure 8.7: Incremental vector displacement along one
profile .......................................... 69
Figure 8.8: Incremental vector displacement along-strike ..... 70
Figure 9.1: Degree of localization and aspect ratios of
active structures ................................ 71
Figure 9.2: Frequency-size distribution of active
structures on the orogen scale ................... 72
Figure 9.3: Power Spectra of spatial distribution of active
structures ....................................... 74
Figure 9.4a: Spatial distribution of earthquakes,
Central Andes .................................... 75
Figure 9.4b: Frequency-size distribution of neighbouring
earthquakes, Central Andes ....................... 76
Figure 9.4c: Magnitude-frequency distribution of
earthquakes, Central Andes ....................... 76
Figure 9.5: Relation of causes and effects ................... 79
List of Tables
Table 6.1: Scaling parameters of the granular experiments .... 30
Table 6.2a: Coefficients of Internal Friction, Cohesion,
Density ........................................... 31
Table 6.2b: Coefficients of Basal Friction, Cohesion,
Density ........................................... 31
Table 6.3: Basal and internal friction coefficients used
for Figure 6.2 .................................... 39
Table 7.1: Scaling parameters of the viscous-brittle
experiments ....................................... 47
Table 7.2: Initial characteristics and resulting patterns
of vise experiments ............................... 48
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