--> Abstract: Tidal Pumping As A Diagenetic Agent, by E. A. Shinn, C. D. Reich, and T. D. Hickey; #90928 (1999).

Datapages, Inc.Print this page

SHINN, E. A., C. D. REICH, and T. D. HICKEY
USGS, St. Petersburg, FL

Abstract: Tidal Pumping as a Diagenetic Agent

Recent submarine groundwater research using dye tracers, pressure transducers, underwater manometers, and other observations in more than 80, 1- to 20- m -deep monitoring wells beneath Florida Bay and the reef tract have revealed an efficient natural pump and significant rates of flow that might explain regions of either submarine cementation or marine dissolution. Meter-range tides on the seaward side of the Florida Keys versus cm-range tides on the bay side of the Keys result in reversing positive and negative groundwater heads exceeding 24 cm. Significantly, head-pressure and subsurface groundwater flow through the subjacent Pleistocene limestone decreases to near zero with distance from the Keys. The requirement of a linear island to produce reversing pressure heads therefore suggests a predictable geometry of pore occlusion and/or creation. Because of climate, waters pumped by tides in the Florida Keys create rather than occlude porosity. However, carbonate-saturated waters in arid climates under similar tidal/island conditions, such as in the Persian Gulf, precipitate rather than dissolve calcium carbonate. Thus, the linear island-dependent porosity/cementation halo-effect driven by tidal pumping may provide a new conceptual model for predicting porosity trends in modern and ancient carbonate reservoirs.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas