Geometric and experimental models of extensional fault-bend folds

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

We use geometric and experimental models to study the development of extensional fault-bend folds. The geometric models show that fault shape, fault displacement, and patterns of aggradation/erosion profoundly affect the distribution of growth beds, the magnitude and direction of dip of pregrowth and growth beds, and the location and dip of the outer limit of folding in pregrowth and growth beds. Complex structural and stratigraphic patterns develop if the rate of aggradation/ erosion relative to the rate of fault displacement changes through time. The experimental models (with dry sand and wet clay) show that several deformational styles can accommodate extensional fault-bend folding. In sand models, a few, relatively major, secondary antithetic normal faults accommodate most hanging wall deformation. Pregrowth layers, although faulted, remain flat. The effective shear direction parallels the antithetic normal faults, and the shear angle is about 60°-65°. In clay models, numerous, relatively minor, secondary normal faults (antithetic and synthetic) and cataclastic flow accommodate most hanging wall deformation. The deformed pregrowth and growth layers dip gently toward the main fault. The effective shear angle (35°-50°) is considerably less than the dip of the antithetic normal faults. In the sand models and geometric models with a large shear angle (60°), more displacement occurs on the main normal fault and the hanging wall collapses in a relatively narrow zone. In the clay models and geometric models with a small shear angle (35°), less displacement occurs on the main normal fault. Instead, the hanging wall stretches substantially and collapses in a relatively wide zone.

Original languageEnglish (US)
Pages (from-to)285-305
Number of pages21
JournalGeological Society Special Publication
Volume253
DOIs
StatePublished - May 15 2006

Fingerprint

fold
normal fault
hanging wall
dip
Clay
fault displacement
Sand
aggradation
clay
sand
folding
Erosion
erosion

All Science Journal Classification (ASJC) codes

  • Water Science and Technology
  • Ocean Engineering
  • Geology

Cite this

@article{4c174acdb75f43518c33877267274997,
title = "Geometric and experimental models of extensional fault-bend folds",
abstract = "We use geometric and experimental models to study the development of extensional fault-bend folds. The geometric models show that fault shape, fault displacement, and patterns of aggradation/erosion profoundly affect the distribution of growth beds, the magnitude and direction of dip of pregrowth and growth beds, and the location and dip of the outer limit of folding in pregrowth and growth beds. Complex structural and stratigraphic patterns develop if the rate of aggradation/ erosion relative to the rate of fault displacement changes through time. The experimental models (with dry sand and wet clay) show that several deformational styles can accommodate extensional fault-bend folding. In sand models, a few, relatively major, secondary antithetic normal faults accommodate most hanging wall deformation. Pregrowth layers, although faulted, remain flat. The effective shear direction parallels the antithetic normal faults, and the shear angle is about 60°-65°. In clay models, numerous, relatively minor, secondary normal faults (antithetic and synthetic) and cataclastic flow accommodate most hanging wall deformation. The deformed pregrowth and growth layers dip gently toward the main fault. The effective shear angle (35°-50°) is considerably less than the dip of the antithetic normal faults. In the sand models and geometric models with a large shear angle (60°), more displacement occurs on the main normal fault and the hanging wall collapses in a relatively narrow zone. In the clay models and geometric models with a small shear angle (35°), less displacement occurs on the main normal fault. Instead, the hanging wall stretches substantially and collapses in a relatively wide zone.",
author = "Martha Withjack and Roy Schlische",
year = "2006",
month = "5",
day = "15",
doi = "10.1144/GSL.SP.2006.253.01.15",
language = "English (US)",
volume = "253",
pages = "285--305",
journal = "Geological Society Special Publication",
issn = "0305-8719",
publisher = "Geological Society of London",

}

Geometric and experimental models of extensional fault-bend folds. / Withjack, Martha; Schlische, Roy.

In: Geological Society Special Publication, Vol. 253, 15.05.2006, p. 285-305.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Geometric and experimental models of extensional fault-bend folds

AU - Withjack, Martha

AU - Schlische, Roy

PY - 2006/5/15

Y1 - 2006/5/15

N2 - We use geometric and experimental models to study the development of extensional fault-bend folds. The geometric models show that fault shape, fault displacement, and patterns of aggradation/erosion profoundly affect the distribution of growth beds, the magnitude and direction of dip of pregrowth and growth beds, and the location and dip of the outer limit of folding in pregrowth and growth beds. Complex structural and stratigraphic patterns develop if the rate of aggradation/ erosion relative to the rate of fault displacement changes through time. The experimental models (with dry sand and wet clay) show that several deformational styles can accommodate extensional fault-bend folding. In sand models, a few, relatively major, secondary antithetic normal faults accommodate most hanging wall deformation. Pregrowth layers, although faulted, remain flat. The effective shear direction parallels the antithetic normal faults, and the shear angle is about 60°-65°. In clay models, numerous, relatively minor, secondary normal faults (antithetic and synthetic) and cataclastic flow accommodate most hanging wall deformation. The deformed pregrowth and growth layers dip gently toward the main fault. The effective shear angle (35°-50°) is considerably less than the dip of the antithetic normal faults. In the sand models and geometric models with a large shear angle (60°), more displacement occurs on the main normal fault and the hanging wall collapses in a relatively narrow zone. In the clay models and geometric models with a small shear angle (35°), less displacement occurs on the main normal fault. Instead, the hanging wall stretches substantially and collapses in a relatively wide zone.

AB - We use geometric and experimental models to study the development of extensional fault-bend folds. The geometric models show that fault shape, fault displacement, and patterns of aggradation/erosion profoundly affect the distribution of growth beds, the magnitude and direction of dip of pregrowth and growth beds, and the location and dip of the outer limit of folding in pregrowth and growth beds. Complex structural and stratigraphic patterns develop if the rate of aggradation/ erosion relative to the rate of fault displacement changes through time. The experimental models (with dry sand and wet clay) show that several deformational styles can accommodate extensional fault-bend folding. In sand models, a few, relatively major, secondary antithetic normal faults accommodate most hanging wall deformation. Pregrowth layers, although faulted, remain flat. The effective shear direction parallels the antithetic normal faults, and the shear angle is about 60°-65°. In clay models, numerous, relatively minor, secondary normal faults (antithetic and synthetic) and cataclastic flow accommodate most hanging wall deformation. The deformed pregrowth and growth layers dip gently toward the main fault. The effective shear angle (35°-50°) is considerably less than the dip of the antithetic normal faults. In the sand models and geometric models with a large shear angle (60°), more displacement occurs on the main normal fault and the hanging wall collapses in a relatively narrow zone. In the clay models and geometric models with a small shear angle (35°), less displacement occurs on the main normal fault. Instead, the hanging wall stretches substantially and collapses in a relatively wide zone.

UR - http://www.scopus.com/inward/record.url?scp=33646399144&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33646399144&partnerID=8YFLogxK

U2 - 10.1144/GSL.SP.2006.253.01.15

DO - 10.1144/GSL.SP.2006.253.01.15

M3 - Article

AN - SCOPUS:33646399144

VL - 253

SP - 285

EP - 305

JO - Geological Society Special Publication

JF - Geological Society Special Publication

SN - 0305-8719

ER -