DOI: 10.25921/rnf6-mn47
title: NOAA/WDS Paleoclimatology - San Diego County California Marine Terrace Quaternary Aminostratigraphy

description: A series of 16 marine terraces record Quaternary paleogeography and tectonic history for the coastal region of San Diego County. Radiometric ages and aminostratigraphy are used, in combination with terrace elevations, to derive average uplift rates and regional correlation of shoreline features. Racemization (AAR) data for multiple taxa at 33 localities are reported here as presented in the published summary and also as raw data for all samples.
description: Extent of Racemization (D/L) data for mollusks from Pleistocene 
marine terrace deposits along the California coast, San Diego area. 

Samples collected by numerous investigators, primarily 
J.P. Kern and T.K. Rockwell, San Diego State University, 
K.R. Lajoie (US Geological Survey), G.L. Kennedy 
(USGS and Los Angeles County Museum of Natural History), 
and J.F. Wehmiller.  Some samples from existing USGS 
collections also included. 

Samples collected and prepared between 1975 and 1983. 
Samples prepared and analyzed at the University of Delaware, 
Newark DE, Lab PI John F. Wehmiller. Some samples also collected 
and analyzed by J.L. Bada (UC San Diego) and colleagues. 

Locality ID = formal or informal name used by collectors 
              and maintained in U Delaware database 
Site name = similar to locality ID; refers to designations 
            in Kern and Rockwell., 1992 
Terrace names from Kern and Rockwell, 1992 
All collection sites are located within the area of the San Diego 
1:100,000 US Geological Survey Topographic Map. 

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 
D/L values reported as peak height ratios 
Lab Code 
Sample ID = identity of specific shell analyzed (samples analyzed 
            at UCSD given identity for use in Delaware database) 
Analytical method: GC = gas chromatography, used for multiple amino acids; 
                        HPLC used for determination of A/I values 
Subsample ID =  usually the same as sample ID; repeat fragments 
                of same shell will have unique identification 
Ratio type = Peak Height ratios used for all results from GC; 
             peak height ratios assumed for all results for HPLC 

D/L values are reported as the means of multiple chromatograms, 
usually at least 3. 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. 


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 

P = Protothaca 
S = Saxidomus 
M = Macoma 
C = Chione 
O = Ostrea 
T = Tivela 
My = Mytilus 

SDSU   San Diego State University 
SDSNH  San Diego Society of Natural History 
LACM   Los Angeles County Museum of Natural History 
USGS   US Geological Survey 
WCC    Woodward Clyde collections (sent to Delaware for analysis) 
UDEL   University of Delaware 
UCSC   University of California, San Diego 
   
In the "Published data summaries", mean values and number 
of samples may not correspond exactly to the raw data 
reported on the "Individual sample results" page because 
of the way results were grouped by Kern and Rockwell (1992),  
or because of the way analytical results have been re-evaluated. 
Conclusions in the original publication are not affected.