DOI: 10.25921/hvwr-1j98
title: NOAA/WDS Paleoclimatology - Cape Lookout North Carolina Quaternary Aminostratigraphy

description: Amino acid enantiomeric ratio data are presented for Pleistocene mollusks obtained from a suite of core samples from both onshore and offshore sites, southeastern North Carolina. The study areaincludes vibracore samples from the Southern Outer Banks, both north and south of Cape Lookout, NC, and vibracore samples from Onslow Bay, southwest of Cape Lookout.  Additional samples from onshore sites southwest of Cape Fear and from subsurface sites in Dare County, NC are used for comparison with the Cape Lookout results.  Core samples have been obtained by researchers at Duke University, the University of South Florida, the US Geological Survey, East Carolina University, and the University of Delaware.  Multiple aminozones are identified in the region, representing ages from early, middle, and late Pleistocene.  All aminozones are recognized within the suite of cores from the Cape Lookout area, but there is a notable absence of most of the mid- to late-Pleistocene aminozones from the area south-southwest of Cape Fear. These observations suggest that the late Quaternary record is quite incomplete in the region of the Cape Fear Arch.
description: Extent of Racemization (D/L) data for mollusks from Pleistocene 
coastal units, onshore and offshore portions of the Atlantic Coastal 
Plain, southeastern North Carolina. 

Cores from Portsmouth, Core, Shackleford, and Bogue Banks (NC) were obtained 
by scientists from Duke University. 
Cores from Core Sound and Onslow Bay (NC) were obtained by scientists 
from the University of South Florida. 
Cores from Ponzer and LB sites (NC) were obtained by scientists 
from the US Geological Survey, Reston VA. 
Cores from Dare County, NC were obtained by scientists 
from East Carolina University. 
Stetson Pit (NC) samples were obtained by scientists from 
Duke University and the University of Delaware. 


Samples prepared and analyzed at the University of Delaware, Newark DE. [UDEL]
Lab PI John F. Wehmiller and Linda L. York  mid 1980's
and at the University of South Florida (USF)  Lab PI D.F. Belknap  (early 1980's)

Pretreatment: Fragments cut from shell valves; surface cleaning 
with dental tools; dilute HCl and distilled water wash; air dry 
AA fraction="amino fraction" 
THAA = total hydrolyzable amino acids;  
FAA = free amino acids (zero hydrolysis time) 
Hydrolysis procedure: 6N HCl 22 hours 105 deg C (for THAA only) 
Bleach: No 
Instrumental programming: GC temperature program; HPLC buffer gradient 
Blank corrections: no 
Response factors: no  

Lab Code UDEL= University of Delaware; USF = University of South Florida

Sample ID = identity of specific shell analyzed
Analytical method: GC = gas chromatography, used for multiple amino acids; 
Ion-exchange High Pressure Liquid Chromatography used for determination of A/I values  (HPLC)
Subsample ID =  usually the same as sample ID; repeat fragments of same 
shell will have unique identification
Ratio type =  (peak area or peak height ratios)


D/L values are reported as the means of multiple chromatograms, 
usually at least 2. For GC results, in most cases sample derivatives 
were analyzed using more than one GC column.

Samples selected for analysis were chosen because they appeared 
to be the most robust specimens among those available,  In most cases, 
samples were not whole valves.  Abraded, rounded, or chalky fragments 
were avoided where possible, and multiple shells from each collection 
were analyzed in almost all cases.  No data screening procedures have been applied.
No interlab sample comparisons were made during the period of these analyses.

Information on sample quality (fragment, whole shell, abraded, chalky, etc.
will be compiled for a future version of this datafile.

Abbreviations:

A/I     D-alloisoleucine/L-isoleucine
Ala     Alanine
Asx     Aspartic acid and asparagine
Glx     Glutamic acid and glutamine
Leu     Leucine
Phe     Phenylalanine
Pro     Proline
Val     Valine

9999 = no data available for this amino acid in this sample

UDAMS = University of Delaware AMinoStratigraphy locality designation