|
Honduras Geology (updated 7/19/98)
Preliminary Stratigraphy and Structure along the Rió Patuca
and Rió Wampú, La Mosquitia, Honduras. (Rogers, R.D.
1994. Geological Society of America, 1994 Annual Meeting Program with abstracts,
p. A-247).
ROBERT D. ROGERS
Foster Wheeler Environmental Corp.
10900 NE 8th Street, Bellevue, WA 89004
Recent 1:50,000 scale geologic mapping, at the confluence of the Río
Patuca and the Río Wampú of eastern Honduras, reveals new
details of the stratigraphy and structure.
Phyllite, slate, schist, and quartzite of the Jurassic-Cretaceous Honduras
Group form the northeast trending highlands north and east of the Río
Patuca. This unit appears to be a weakly metamorphic equivalent of the
Jurassic Aqua Fría Formation. Thick-bedded micrites and a few thin
sparry and biomicrite beds comprise the Cretaceous Atima Formation of the
Yojoa Group, which forms the Montañas de Colón south of the
Río Patuca. Thinly bedded shale, arenite, and graywacke with minor
limestone and quartz pebble conglomerate conformably overlie the Atima
limestone. This shale is found along the Río Patuca, east of the
Río Wampú, and in northeast striking valleys within the Montañas
de Colón. The Upper Cretaceous Valle de Angeles Group, consisting
of redbeds of fine-grained sandstone and lithic conglomerate, unconformably
overlies the shale. These redbeds are exposed in the Río Patuca
lowlands and flank the metamorphic highlands. Isolated basalt and andesite
flows occur in the redbeds in the Río Patuca lowlands and form thick
flows along the Río Wampú. K-AR chronology yield ages of
80.7±4.3 to 70.4±4.3 for the mafic flows (Weiland et al.
1993). The redbeds grade upward to a thick cobble and boulder breccia containing
clasts of the mafic volcanic rocks. This breccia flanks the southeast side
of the metamorphic highlands and forms the highlands south of the Río
Wampú.
South of the Río Patuca, northwest verging thrust faults place
Cretaceous Atima limestone over Upper Cretaceous Valle de Angeles redbeds
and repeats the Atima section in the Montañas de Colón. The
northeast trending metamorphic highland and the thick breccia north of
Río Patuca expose large folds. Small folds, thrust faults, and tear
faults within the redbeds express northwest-southeast compression. North-northeast
trending dextral strike-slip faults cross-cut the thrust faults of the
Montañas de Colón.
Return to Contents of Honduras Geology.
|
