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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 57 (1973)

Issue: 4. (April)

First Page: 802

Last Page: 802

Title: Sedimentary Environments, Pennsylvanian and Early Permian, Southeastern Arizona: ABSTRACT

Author(s): Charles A. Ross

Article Type: Meeting abstract


In southeastern Arizona, Pennsylvanian and Early Permian strata have 15 complex transgressive and regressive cycles. Sedimentary environments were influenced primarily by a stable central Arizona shelf (divisible into Papago inner shelf, San Pedro outer shelf, and Mogollon inner shelf) and an unstable Pedregosa basin on the southeast.

Morrowan and earliest Derryan deposits (Black Prince Limestone) have a basal red clastic unit overlain by thin, sheetlike carbonate units. During late Derryan and early and middle Desmoinesian deposition (lower part of Horquilla Limestone), successive carbonate banks separated the 3 parts of the central Arizona shelf, but there was little differentiation of sediments on the San Pedro outer shelf and in the Pedregosa basin. During the latter part of the Desmoinesian, a clastic influx from the north initiated carbonate-poor depositional cycles.

Missourian and Virgilian deposition (upper part of Horquilla Limestone) produced more clearly differentiated carbonate-bank margins around the Pedregosa basin and San Pedro outer shelf. Northward, these strata become dominantly clastic and pass into interdistributary bay and lagoonal deposits and supratidal, deltaic redbeds and conglomerates of the Supai Formation.

Wolfcampian depositional environments (part of Supai and Earp Formations) shifted southeast with time. On the Mogollon inner shelf, supratidal deltas and gypsiferous lagoonal deposits form this part of the Supai Formation; and on the San Pedro outer shelf, shallow-shelf sandstones, siltstones and shales intertongue with a few thin limestones. Massive, lenticular carbonate banks enclosed the Pedrogosa basin, and within the basin, dark fetid clastics and carbonates suggest restricted environments. Latest Wolfcampian or early Leonardian sediments (part of Supai and Earp Formations) are sandy dolostones and siltstones with impoverished faunas that suggest a series of poorly aerated lagoons.

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Copyright 1997 American Association of Petroleum Geologists