Neogene tectonics of northern Central America prior to offset across the polochic fault

Conference · Tue Jan 01 04:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6651903

Burkart, B; Sanchez-Barreda, L A; Deaton, B C

The reconstruction which removes 130 km of documented left slip across the Polochic fault of northern Guatemala and southern Chiapas juxtaposes the foundered block of the Gulf of Tehuantepec and extensional terrane of Guatemala, lining up prolongations of the Motagua and Jocotan faults with known structures along the coastal margin of the Chiapas massif and within the Gulf. Coast-parallel faults with sinistral displacement, located along the margins of the Chiapas depression, were also active during the Miocene time interval of south-easterly migration of the Gulf of Tehuantepec block. Extensional terrane is well expressed in Guatemala and Honduras south of the Jocotan boundary fault, beginning where the southeasterly-moving block encounters the abrupt bend in the boundary fault. This complex plate boundary became simpler when the left-lateral, east-west-trending Polochic fault sliced across the isthmus in late Miocene, offsetting Laramide structures and the arcuate Neogene plate boundary faults. During its time of major activity the Polochic served as the principal plate boundary fault, across which the major displacement occurred. Today the western part of the NOAM-CARIB plate boundary is diffuse. From western Guatemala and southern Chiapas, where buckling and locking of the Polochic fault has taken place, displacement is distributed among countless shears which extend in a belt from western Guatemala across the Chiapas massif to the western landframe of the Gulf of Tehuantepec.

• Research Organization: Univ. of Texas, Arlington (USA)
• OSTI ID: 6651903
• Report Number(s): CONF-8510489-
• Conference Information: Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580100 -- Geology & Hydrology-- (-1989)
580201* -- Geophysics-- Seismology & Tectonics-- (1980-1989)
CENOZOIC ERA
CENTRAL AMERICA
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
LATIN AMERICA
MIOCENE EPOCH
ORIENTATION
PLATE TECTONICS
TECTONICS
TERTIARY PERIOD