18 Surficial and Subsurface Geology and Hydrogeology of the Cape Fear River Basin

Friday, 25 March 2011
8:00 AM - 11:30 AM
Salon A

CENOMANIAN TO SANTONIAN SEQUENCE STRATIGRAPHY OF THE KURE BEACH AND ELIZABETHTOWN CORES, CAPE FEAR RIVER BASIN, NC

Paper number: 18-3
Program: Theme Sessions
Time: 8:40 AM – 9:00 AM

Authors

Abstract

This study identifies stratigraphic sequences and depositional facies in two cores (Elizabethtown and Kure Beach), and documents Cenomanian to Santonian sea-level changes along the southeastern Coastal Plain of North Carolina, using lithostratigraphy, strontium-isotope stratigraphy, biostratigraphy, and geophysical logs. In the Elizabethtown core, four sequences are identified as follows, from oldest to youngest: Clubhouse Crossroads II, Pleasant Creek I, Pleasant Creek II and Tar Heel I. In the Kure Beach core, five sequences are identified: Clubhouse Crossroads II, Fort Fisher, Pleasant Creek I, Pleasant Creek II and Tar Heel I.

The Cenomanian Clubhouse Crossroads II sequence is represented in the Elizabethtown core by a lowstand systems tract (LST), which is uncommonly preserved, and in the Kure Beach core by a transgressive systems tract (TST), maximum flooding surface (MFS), and highstand systems tract (HST). This sequence is the only known sequence in the North Carolina coastal plain that can be correlated between two cores and that contains a complete cycle of mean sea-level rise and fall. The Coniacian Fort Fisher sequence is present only in the Kure Beach core and is represented by a HST. It is assigned to calcareous nannofossil zone CC13b. The Pleasant Creek I sequence is Coniacian to Santonian in age and is present in both cores. It consists of a TST, a MFS, and a HST. At Elizabethtown, the HST can be subdivided into early and late tracts. This sequence is assigned to calcareous nannofossil zones CC14, CC15, and CC16.

In the Elizabethtown core, the Santonian Pleasant Creek II sequence is represented by a shelf-margin systems tract, a tidal ravinement surface, a TST, a MFS, an early HST, and a late HST. The TST and the HST can be traced to the Kure Beach core, although the HST cannot be subdivided in that core. This sequence is assigned to calcareous nannofossil zones CC16 and CC17. The base of the Tarheel I sequence in the Elizabethtown core is a tidal ravinement surface followed by a TST, MFS, and HST that can be correlated to the Kure Beach core. This sequence is assigned to calcareous nannofossil zones CC18 and CC19.