RF - REFERENCE SOURCE: GeoRef, Copyright 2000, American Geological Institute.
IS - ISSN: 1052-8423
CO - CODEN: #02354
AN - ACCESSION NUMBER: 1990-044406
UD - UPDATE CODE: 1990
Registro 4379 de 5614 - GeoRef Disc 3: 1985-1992
BK - BOOK TITLE: Geology and petrography of pre-Mesozoic and Mesozoic rocks of the northern Rio Nima area, Departamento Del Valle, Colombia, S.A.
BA - BOOK AUTHORS: Bennett-Marvin-Edward III
CP - COUNTRY OF PUBLICATION: United-States
PY - PUBLICATION YEAR: 1986
DG - DEGREE GRANTED: Master's
DI - DEGREE GRANTING INSTITUTION: Stephen F. Austin State University. Nacogdoches, TX, United States. Pages: 80. 1986.
LA - LANGUAGE: English
AB - ABSTRACT: The Romeral Fault is a proposed ancient plate boundary located on the western slope of the Central Cordillera in west-central Colombia. Geologic mapping adjacent to the fault shows it to separate eastern Palaeozoic or older, regionally metamorphosed rocks of the Cajamarca Group from western Cretaceous pillow basalts and diabases of the Diabase Group. Cajamarca Group rocks consist primarily of sericite-quartz schists, greenschists and blackschists and are here considered products of an Early Palaeozoic island chain-type, calc-alkaline vulcanism. Near vertical, imbricate, reverse faults separate the various lithologies forming individual tectonic sheets. An amphibolite-migmatite block with a reset date of 117 + or - 6 m.y. was tectonically emplaced and two Tertiary plutons were intruded into this group. Late Mesozoic, tectonic reactivation of the western continental margin resulted in lateral and vertical transport of Diabase Group rocks, placing them in fault contact with Cajamarca Group rocks. Reactivation of the imbricate faults by the Miocene Andean Orogeny resulted in shearing and cataclasis along many tectono-lithologic boundaries and vertical fault movement accompanied by uplifting of the Central Cordillera.