noaa-other-20287 United Kingdom Shell Amino Acid Racemization Data Penkman, K.E.H.; Preece, R.C.; Keen, D.H.; Maddy, D.; Schreve, D.C.; Collins, M.J. United Kingdom Shell Amino Acid Racemization Data 2016-06-14 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/20287 Investigator K.E.H. Penkman Investigator R.C. Preece Investigator D.H. Keen Investigator D. Maddy Investigator D.C. Schreve Investigator M.J. Collins earth science paleoclimate others geoscientificInformation 700000 cal yr BP 0 cal yr BP Complete 50 54 -3 7 Continent Europe Northern Europe British Isles UKAAR>LATITUDE >LONGITUDE None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII K.E.H. Penkman, R.C. Preece, D.H. Keen, D. Maddy, D.C. Schreve, M.J. Collins 2007 Quaternary Science Reviews 26 22-24 2958-2969 10.1016/j.quascirev.2007.06.034 http://www.sciencedirect.com/science/article/pii/S0277379107002570

Until recently few studies of amino acid racemization of fossil bivalves and gastropods collected from river terrace deposits in Europe were based on the analysis of the intra-crystalline fraction. Instead they were based on the epimerization (racemization) of a single amino acid, isoleucine, and its inter-conversion to alloisoleucine. This paper presents data from the analysis of the intra-crystalline fraction of the shells, using a preparation technique of sample bleaching to remove the leachable matrix, thus leaving a component that exhibits closed-system behaviour. Reverse-phase HPLC separation with fluorescence detection allows the interpretation of four amino acids in detail: aspartic acid, glutamic acid, alanine and valine. The intra-crystalline fraction offers greater potential for improved resolution, especially when combined with the analysis of multiple amino acid d/l values, which racemize at different rates. This is explored using three species of freshwater gastropods (Bithynia tentaculata and troschelii, Valvata piscinalis) and the bivalve Corbicula. Sites of different ages within the Lower Thames river terrace sequence are used as a stratigraphical framework, with samples from other southern UK sites providing supplementary evidence. The results indicate better resolution using the intra-crystalline fraction over that obtained using unbleached shells, with differentiation possible at sites of up to MIS 7 age. However, for older sites, although values are always higher, the separation is less successful. A species effect has been identified between the gastropod shells. Despite the analysis of intra-crystalline protein, amino acid data from Corbicula remain problematical. Preliminary data on the opercula from Bithynia indicate that better resolution is possible, particularly at older sites. STUDY NOTES: Amino acid racemization (D/L) data on freshwater gastropod (Bithynia, Valvata) and bivalve (Corbicula) shells from sites in the United Kingdom. Data include extent of amino acid racemization (D/L) for aspartic acid (Asx), glutamic acid (Glx), serine (Ser), alanine (Ala) and valine (Val).

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/aar/penkman2007uk/penkman2007uk.xlsx Excel Data File; Penkman et al. 2007 United Kingdom Shell Amino Acid Racemization Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/aar/penkman2007uk/penkman2007uk.txt Text Data File; Penkman et al. 2007 United Kingdom Shell Amino Acid Racemization Data USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11