Blind imbricate complexes as exploration targets in fold and thrust belts

Conference · Thu May 01 04:00:00 EDT 1986 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:5202163

Woodward, N B

Field mapping of the Absaroka thrust system of Wyoming documents the existence of thrust and fold complexes in lower Paleozoic rocks that never breach the broadly folded, overlying, upper paleozoic section. Rather than single blind thrusts, the complexes include from two to five 5- to 10-km long imbricate thrust that die out upward into brecciated, cleaved, and tightly folded rock. The tight lower folds are damped disharmonically upward into broad folds at the Pennsylvanian level. Stylolitic pressure solution cleavage and brittle fractures break the rock into 50 cm to 5 m pieces, and create extensive fracture porosity. These complexes show flat or shallow-dipping contraction faults in higher stratigraphic units. They are not duplexes, however, because the core faults never merge with any roof thrust. The effect higher in the section is to create large anticlinal structures above the Mississippian that may reach 5 km wide and 20 km long. In contrast to the expected ramp anticlines in thrust belts, the blind imbricate complexes will probably not lie along parallel, linear, thrust-ramp trends. They provide a new type of exploration target and a model for the deep structure of folds whose size or stratigraphy indicates their origin is not related to ramping. There is no reason why this type of structure should be unique to any one thrust belt or stratigraphic package.

• Research Organization: Univ. of Tennessee, Knoxville
• OSTI ID: 5202163
• Report Number(s): CONF-860624-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 70:5
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
EXPLORATION
FEDERAL REGION VIII
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
GEOLOGY
MINERAL RESOURCES
MISSISSIPPIAN PERIOD
NORTH AMERICA
PALEOZOIC ERA
PETROLEUM DEPOSITS
RESOURCES
STRATIGRAPHY
USA
WESTERN US OVERTHRUST BELT
WYOMING