The state of stress in the limb of the Split Mountain anticline, Utah

Constraints placed by transected joints

Laura J. Silliphant, James Terry Engelder, Michael R. Gross

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

Transected joints (i.e. systematic joints that strike at an angle to the present fold axis trend) occur on the flanks of Split Mountain, a Laramide anticline near the eastern end of the Uinta Mountains, Utah. The common orientation on both flanks for these WNW-striking joints is inconsistent with joints driven by a syn-folding stretch normal to the direction of highest curvature. A smaller dispersion of the poles to these transected joints occurs when they are rotated with bedding to their 'pre-fold' orientation. This dispersion of poles is inconsistent with a post-fold genesis in a regional stress field but permits the possibility that these WNW joints propagated as a systematic set prior to Laramide folding. A pre-fold interpretation is substantiated by a regional WNW-striking joint set within Cretaceous and older rocks in the surrounding Piceance, Uinta, and southeastern Sand Wash basins. During tilting accompanying the upfolding of Split Mountain, most joints of this WNW-striking regional set remain locked without slipping under a shear stress. Fracture toughness and frictional strength are two rock properties that serve to lock a joint until a critical resolved shear stress is achieved. A gravity load caused down-dip slip on some joints that were tilted to a dip of about 62°. This suggests that a local principal stress remained roughly vertical during bedding rotation. Assuming fracture strength and friction prevented slip on most joints during tilting, the ratio of least horizontal, Sh, to vertical stress, Sv, at the critical tilt angle was approximately 0.55.

Original languageEnglish (US)
Pages (from-to)155-172
Number of pages18
JournalJournal of Structural Geology
Volume24
Issue number1
DOIs
StatePublished - Jan 1 2002

Fingerprint

anticline
limb
mountain
fold
shear stress
folding
fracture toughness
dip-slip fault
rock property
tilt
stress field
curvature
dip
friction
gravity
Cretaceous
sand

All Science Journal Classification (ASJC) codes

  • Geology

Cite this

Silliphant, Laura J. ; Engelder, James Terry ; Gross, Michael R. / The state of stress in the limb of the Split Mountain anticline, Utah : Constraints placed by transected joints. In: Journal of Structural Geology. 2002 ; Vol. 24, No. 1. pp. 155-172.
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The state of stress in the limb of the Split Mountain anticline, Utah : Constraints placed by transected joints. / Silliphant, Laura J.; Engelder, James Terry; Gross, Michael R.

In: Journal of Structural Geology, Vol. 24, No. 1, 01.01.2002, p. 155-172.

Research output: Contribution to journalArticle

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