Carboniferous biostratigraphy, northeastern Brooks Range, Arctic Alaska

Abstract

GEOLOGICAL SURVEY PROFESSIONAL PAPER 884Eleven microfossil assemblage zones are recognized in two sections of Carboniferous rocks in the northeastern Brooks Range, correlated with six other previously described sections, and tied to the Cordilleran and Eurasian standards

Biostratigraphy and regional relations of the Mississippian Leadville limestone in the San Juan Mountains, southwestern Colorado

“…A detailed account of the Arroyo Penasco Group, its lithology, microfossils, and geologic history can be found in Armstrong and Mamet (1974). The following description is, in part, abstracted from that report.…”

“…Or it could be the result of dissolution by meteoric ground water of interbedded carbonate rocks and gypsum (Armstrong, 1967) during Late Mississippian and Early Pennsylvanian. Armstrong and Mamet (1974) proposed the name Turquillo Member for a thick-bedded mudstonewackestone, rich in foraminifers and bothrolites, that overlies either the Macho Member or, where missing, the Espiritu Santo Formation. The Turquillo Member is 2.5 m thick at the Ponce de Leon Springs section east of Taos.…”

“…It is absent in the Pecos River Canyon. Foraminifers in the Turquillo Member indicate the passage of zone 12-13, which is the age equivalent of the Salem-St. Louis boundary (Armstrong and Mamet, 1974).…”

“…Regional correlation diagram of the Leadville Limestone of the San Juan Mountains, Colo., and Mississippian rocks in adjacent areas. Mamet (1974) Calcite pseudomorphs of gypsum are common in the carbonate rocks of the Espiritu Santo Formation. Armstrong (1967) and Armstrong and Mamet (1974) suggested the possibility that the Macho Member, a breccia, may represent a collapse breccia formed by the solution, in Early Pennsylvanian time, of interbedded gypsum and limestone that represent the upper part of the Espiritu Santo Formation in the Sangre de Cristo Mountains of New Mexico.…”

Preliminary investigation of the Lisburne Group, upper Nanushuk River region, central Brooks Range, Alaska

“…The early Mississippian Lisburne Group is exposed in the foreland fold-and-thrust belt of the Brooks Range (Dumoulin and others, 1992) in what is known as the Endicott Mountains allochthon (Mull and others, 1987) and is a component of a larger carbonate system throughout the North American Cordillera and in eastern Russia (Armstrong and Bird, 1976). It is also present in the North Slope subsurface including the Prudhoe Bay area (Bird and Jordan, 1977).…”