Paleoecology and Structure of a Late Silurian-Early Devonian(?) Patch Reef, Northwestern New Jersey: ABSTRACT

Abstract

Quantitative and qualitative field examination of an Upper Silurian-Lower Devonian(?) bioherm in northwestern New Jersey resulted in the identification of at least five distinct lithologic and biotic facies: (1) a basinal lithofacies of medium to thick-bedded pelagic limestones containing few discernable fossils; (2) a peloidal grainstone facies, which is dominated by pelmatozoan fragments and peloidal carbonate grains; (3) a reef-talus facies characterized by a high biotic diversity; (4) a coral-boundstone facies dominated by massive tabulate corals; and (5) a stromatoporoid reef facies composed of large juxtaposed hemispherical stromatoporoids (65%), tabulate corals (30%), and rugose corals (5%). Facies evidence demonstrates that the stromatoporoids and corals organically cemented this buildup into a rigid, wave-resistant structure that controlled its surrounding environment. According to Heckel's 1974 classification of reefs, this type of boundstone lithofacies would indicate an organic framework reef. The patch reef grew in a moderate-to-high energy regime and was developed on a carbonate platform which was situated on the margin of an epeiric sea. Reef growth was progradational and upward in response to a relative rise in sea level. Investigation of the patch reef facies revealed compound growth and accretion zones, in addition to demonstrating distributional patterns similar to those of modern patch reef analogs. End_of_Article - Last_Page 1173------------