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F 3 - Faults, Fractures and Flexures in Three-Dimensions:

F 3 - Faults, Fractures and Flexures in Three-Dimensions: Field Observations at the Dead Sea Basin Ze'ev Reches School of Geology and Geophysics, University of Oklahoma. Multi-scale deformation in basin margins: A. Bending of the crust into the basin B. Zig-zag faulting in basin margins

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F 3 - Faults, Fractures and Flexures in Three-Dimensions:

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  1. F3- Faults, Fractures and Flexures in Three-Dimensions: Field Observations at the Dead Sea Basin Ze'ev Reches School of Geology and Geophysics, University of Oklahoma Multi-scale deformation in basin margins: A. Bending of the crust into the basin B. Zig-zag faulting in basin margins C. Local bending of layers above the faults D. Fractures associated with local bending

  2. Study area Taurus Mts. 200 km N Dead Sea basin Mediterranean Sea Dead Sea Transform Sinai 20 km Arabian plate African plate Arabian plate Sinai subplate

  3. W E W E ? ? ? c b a 5 km A B A. Bending of the crust and basin sedimentation B. Zig-zag faulting in basin margins C. Local bending above the faults D. Fractures associated with bending B A

  4. A. Bending into a pull-apart basin B. Zig-zag faulting in basin margins C. Local bending above the faults D. Fractures associated with local bending 80,185 Dead Sea 1 km (Agnon, 1983) Cumulative fault length: 176 km 40,178 N Emunah-1

  5. a 31005’ 15 m 1 km 31003’ Zig-zag fault in the field (top) Structural map of a typical part of the Dead Sea margins (left). Close-up view of a sand-cake extension experiment (right).

  6. Nahal Parsa section Hazera Fm. Lisan Fm. 10 m W E b 3 2 2 1 ? 2 I 2 1 4 II 3 100m III A. Bending into a pull-apart basin B. Zig-zag faulting due to 3D strain C. Local bending above the faults D. Fractures associated with bending

  7. Bending above faults m=0.0 Surface distribution of tensile fractures 250m Inclined zone of tensile fractures A B A B Flexed layers from Boldt, unpublished B Fault D D Faults C C

  8. A. Bending into a pull-apart basin B. Zig-zag faulting due to 3D strain C. Local bending above the faults D. Fractures associated with bending • Implications: • Faults and fracture orientations • Fracture density distribution

  9. Hever 8 Mishmar (lower) Hever (lower) hever 10 Ye’elim (lower) Bokek (lower) A. Bending into a pull-apart basin B. Zig-zag faulting due to 3D strain C. Local bending above the zig-zag faults D. Fractures associated with bending Hever 7 N 1m Hever 9 fracture orientations

  10. Trends of faults from geologic maps fractures in field Fractures in subsurface Similarity of trends of faults and fractures; Dead Sea margins

  11. E W ~ 50 m 3.3 m Fault zone

  12. a b c N Dead Sea Transform 20cm 200km 2km 200m 20km Areal stress-state Plate-scale stress field Local stress-state

  13. Map ofshminabove zig-zag normal faults (green=tensile). (stresses calculate for 0.5 km depth; faults dip 75o eastward; faults from 2 km to 15 km below surface; dislocations) 5 km Fault strand Trend & relative magnitude of tensile shmin

  14. Large, steeply dipping fractures Gently inclined bedding surfaces Opened zones of unknown origin on borehole surface N E S W N N E S W N CAST images of Emunah-1 borehole 564m of images in depth interval: 1400- 2700m, 550 identified fractures (classes A-D), 73 in classes A-B (used in the analysis).

  15. North Idealized fault pattern, western margins of Dead Sea basin Anderson, 1951 Reches, 1983

  16. Inclined zone of tensile fractures B Flexed layers Fault W E Hazera formation Lisan formation 10 m

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