Abstract

Petrographic analysis of 14 cores penetrating the Inglis and Avon Park Formations (Floridan aquifer) reveals several distinct lithofacies representing multiple regressive-transgressive cycles, aerial exposure, and diagenesis. Evolution of pore spaces varies with the lithofacies and is a function of primary deposition and diagenetic history. The general tendency has been toward obliteration of primary voids by compaction and calcite and dolomite infilling, but several zones show dissolution enlargement.

There is evidence for penecontemporaneous dolomitization in a supratidal environment, as well as post-depositional dolomitization by Mg-rich ground-water flushing. Various dolomite textures can be used to predict the environment of dolomitzation. These textures are (1) replacement dolomitization of the total sediment so that original fabrics are preserved; (2) dolomitization by aggrading neomorphic processes; and (3) replacement dolomitization of fossils and pellets only.

Other diagenetic processes which have affected the lithofacies include dissolution, recrystallization and inversion, and several phases of calcite cementation. The hydrologic regime and the original texture of the carbonate rock controlled the types of cement present. Scalenohedral crystals have been precipitated from marine waters along the test walls of internal chambers of fossils. Small, equant, blocky crystals have precipitated from meniscus fluid in the vadose zone of ground water as coatings along internal chamber walls of fossils and at the contacts between grains. Large rhombohedral crystals have precipitated from fresh water of the phreatic zone as partial and complete infillings of intraparticle and interparticle spaces.

First Page Preview

First page PDF preview
You do not currently have access to this article.