Cenozoic thrust emplacement of a Devonian batholith, northeastern Brooks Range: Involvement of crystalline rocks in a foreland fold-and-thrust belt

Journal Article · Tue May 01 04:00:00 EDT 1990 · Geology; (USA)

OSTI ID:6357552

Wallace, W K; Hanks, C L ^[1]

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1. Univ. of Alaska, Fairbanks (USA)

Involvement of crystalline rocks in thrusting near the foreland basin of a fold-and-thrust belt is relatively uncommon. In the northeastern Brooks Range, the Devonian Okpilak batholith was thrust northward and structurally elevated above adjacent foreland basin deposits during Cenozoic fold-and-thrust deformation. The batholith may have acted initially as a regional structural buttress, but a drop in the basal detachment surface to greater depth south of the batholith resulted in northward transport of the batholith. Shortening within the batholith was accommodated by (1) the development of discrete thrust slices bounded by ductile shear zones, (2) simple shear and development of penetrative mesoscopic and microscopic fabrics throughout the batholith, or both. The Mississippian Kayak Shale, a regional detachment horizon at the base of the overlying cover sequence, is depositionally thin or absent adjacent to the batholith. Thus, most of the cover sequence remained structurally coupled to the batholith during thrusting and was shortened by the development of penetrative structures.

• OSTI ID: 6357552
• Journal Information: Geology; (USA), Journal Name: Geology; (USA) Vol. 18:5; ISSN GLGYB; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ALASKA
CARBONIFEROUS PERIOD
CENOZOIC ERA
DEFORMATION
FEDERAL REGION X
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
NORTH AMERICA
PALEOZOIC ERA
REGIONAL ANALYSIS
ROCKS
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SHALES
SHEAR
STRATA MOVEMENT
TECTONICS
USA