HR: 15:30h
AN: U53A-07 [Abstracts]
TI: Piercing Lines Between Southwest Mexico and the Chortis Block of Northern Central America:
Constraints on Cretaceous Position of Chortis Block
AU: * Rogers, R D
EM: rrogers@geology.csustan.edu
AF: Department of Geology, California State University Stanislaus
University of, 801 W. Monte Vista Ave., Turlock, CA 95382, United States
AB:
Geologic investigations in Honduras and Nicaragua reveal features and structures which correlate to southern
Mexico in sufficient detail to constrain the latest Cretaceous position of the Chortis block along the truncated
southwestern margin of Mexico. Two regional features common to southern Mexico and Honduras are 1) their
Precambrian basement contain both containing Grenville age protoliths and 2) the similar Mesozoic cover of Late
Cretaceous clastic, marine sandstone and shale over Early Cretaceous shallow water platform carbonate rocks.
Three north trending piercing lines are common to southern Mexico and to the Chortis block: 1) north trending
mid-Cretaceous arc and geochemical trends of Teloloapan arc in Mexico and the Manto arc in Honduras; 2) north
trending late Cretaceous structural belts southern Mexico and the Frey Pedro, Comayagua, Minas de Oro and La
Flor structural belts of Honduras and 3) a north trending common magnetic signature in Mexico separating the
Guerrero terrane from the autochthonous terranes of Mexico and in Honduras forming the southwestern edge of
the Precambrian continental basement. A forth piercing line is the east trending alignment of the eastern
Honduras Colon fold belt with late Cretaceous east trending fold belt of southeastern Guatemala. Our best fit
alignment of these features and piercing lines place the northern limit of the Chortis block along the southern
margin of Mexico between Zihuatenejo and Acapulco in the latest Cretaceous and is consistent with 35 degrees
of post-Cretaceous counterclockwise rotation of the Chortis block.
DE: 8150 Plate boundary: general (3040)
SC: Union [U]
MN: 2007 Joint Assembly