Kinematics of the mosquito terrane, Coldfoot Area, Alaska: Keys to Brooks Range tectonics: Final report, Project No. 2

Technical Report · Fri Apr 01 00:00:00 EST 1988

OSTI ID:6607704

Harms, T A; Coney, P J

Within the large-scale geometry of the Brooks Range, the Angayucham terrane occurs as a vast overthrust sheet. From the north flank of the Ruby terrane it underlies the Koyukuk basin and stretches north as the roof thrust to the various nappe terranes of the Brooks Range. The tectonic relationship of the Ruby terrane to the south flank of the Brooks Range lies largely obscured beneath the Angayucham in the eastern apex of the Koyukuk basin. The Mosquito terrane occurs as a window through the Angayucham at this juncture. The composition and structures of the Mosquito terrane reveal that is the result of shear along a sub-horizontal step or flange within the prominent, through-going dextral strike-slip fault system which cuts across the eastern Koyukuk basin and southeastern Brooks Range. Units of the Mosquito were derived from both the Angayucham and Ruby terranes. A consistent tectonic fabric imposed upon them is kinematically linked to the strike-slip system and indicates a northeasterly direction of transport across the terrane. The presence of Ruby-correlative units within the Mosquito suggests the Ruby underlies the Angayucham and that it is in contact with terrances of the southern Brooks Range at that structural level along high-angle strike-slip faults. These relationships demonstrate that an episode of dextral transpression is the latest in the history of terrane accretion and tectonic evolution of the Brooks Range. 35 refs.

• Research Organization: Arizona Univ., Tucson (USA). Dept. of Geosciences
• DOE Contract Number: AC21-84MC21129
• OSTI ID: 6607704
• Report Number(s): DOE/MC/21129-2646; ON: DE89000907
• Resource Relation: Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
ALASKA
GEOLOGY
MOUNTAINS
GEOLOGIC HISTORY
CLASSIFICATION
GEOLOGIC FAULTS
GEOLOGIC MODELS
GROUND UPLIFT
ISOTOPE DATING
MAPPING
METAMORPHISM
OROGENESIS
PROGRESS REPORT
SEDIMENTATION
TECTONICS
AGE ESTIMATION
DOCUMENT TYPES
FEDERAL REGION X
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
NORTH AMERICA
USA
580100* - Geology & Hydrology- (-1989)
580201 - Geophysics- Seismology & Tectonics- (1980-1989)