Abstract: Sequence Stratigraphy of the Late Miocene-Early Pliocene Peace River Formation, Southwestern Florida

Abstract

ABSTRACT Platform-wide carbonate deposition ceased on the south Florida Platform during the early Pliocene for a period of about one m.y. A sequence of late Miocene-age shallow marine sediments containing mixed carbonates and siliciclastics was succeeded by an early Pliocene-age, predominantly siliciclastic, deltaic sequence within the Peace River Formation to temporarily end carbonate deposition on the southern interior part of the Florida platform. The Peace River Formation was deposited from about 11 to 4.3 Ma. It is separated from the underlying, middle Miocene Arcadia Formation by an unconformity with a hiatus of 2 to 4 m.y. The unconformity separating the shallow marine sequence (late Miocene) from the overlying deltaic sequence (early Pliocene) has a hiatal gap of 2 to 6 m.y. depending on geographic location. The unconformity between the upper Peace River Formation and the overlying Tamiami Formation shows a distinctive change in bedding orientation and lithology, but only a minimal hiatus occurs (perhaps 0.2 m.y.). The late Miocene sequence contains a series of shallow marine shoaling-upward parasequences 1 to 9 (depending on location) that are either transgressive or regressive. The early Pliocene sequence is a single prograding deltaic deposit that pinches out from north to south in the central part of the platform.