Northern Spain 23,000 Year Littorina littorea Amino Acid Racemization Data Ortiz, J.E.; Sanchez-Palencia, Y.; Gutierrez-Zugasti, I.; Torres, T.; Gonzalez-Morales, M. Ortiz, J.E. Sanchez-Palencia, Y. Gutierrez-Zugasti, I. Torres, T. Gonzalez-Morales, M. earth science/paleoclimate/others (Northern Spain caves>LATITUDE >LONGITUDE ) The inter-and intra-crystalline fractions of the topshell Phorcus lineatus recovered from modern specimens and shells from archaeological sites in Northern Spain covering Neolithic, Mesolithic, and Upper Magdalenian periods were examined for amino acid composition and racemisation over time. The main loss of proteins from the inter-crystalline fraction occurred within the first 6000 years after the death of the organism. In contrast, the intra-crystalline fraction isolated by bleaching-with a different protein composition to that of the inter-crystalline fraction-appeared to behave like a closed system for at least 12.6 ka, as reflected by the lack of a significant decrease in amino acid content. However, changes in the relative composition of the amino acids present in these shells occurred during this period. The concentration of aspartic acid remained almost constant with age within the intra-crystalline fraction and its contribution to the total amino acid content also remained the same. Good correspondence was obtained between Asx D/L values in unbleached and bleached samples and age, thereby allowing the dating of archaeological sites and the determination of chronometric age. STUDY NOTES: Amino acid racemization (AAR) data in mollusc samples (Littorina littorea) from archaeological levels in Northern Iberian Peninsula caves. LABORATORY AND ANALYTICAL INFORMATION Lab: Biomolecular Stratigraphy Laboratory (E.T.S.I.Minas) Lab PI: José E. Ortiz, Yolanda Sánchez-Palencia, Trinidad Torres Preparation date: Apr 2010 through Nov 2018 Pretreatment: HCl 2N AA fraction = AMINO FRACTION Hydrolysis procedure: 20 hr at 100°C in 20 µL/mg of 7 M HCl under N2 Bleach: No/yes Analytical method: RLPC Instrumental programming: RPLC buffer gradient Concentration yes Area or height ratio: Area Blank corrections: none Response factors: none Data screening criteria: Rejection criteria: 1 = L-Ser/L-Asp > 0.8; 2 = Asp or Glu D/L > ± 2s beyond group mean 3 = Asp or Glu D/L fall off the covarience trend NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Ortiz, J.E. Investigator : Sanchez-Palencia, Y. Investigator : Gutierrez-Zugasti, I. Investigator : Torres, T. Investigator : Gonzalez-Morales, M. 2019-06-17 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/27070 https://www1.ncdc.noaa.gov/pub/data/paleo/aar/ortiz2018spain/ortiz2018spain.txt https://www1.ncdc.noaa.gov/pub/data/paleo/aar/ortiz2018spain/ortiz2018spain.xlsx https://www1.ncdc.noaa.gov/pub/data/paleo/aar/ortiz2018spain/ortiz2018spain.txt https://www1.ncdc.noaa.gov/pub/data/paleo/aar/ortiz2018spain/ortiz2018spain.xlsx English https://www.ncdc.noaa.gov/paleo/study/27070 https://www1.ncdc.noaa.gov/pub/data/paleo/aar/ortiz2018spain/ortiz2018spain.txt https://www1.ncdc.noaa.gov/pub/data/paleo/aar/ortiz2018spain/ortiz2018spain.xlsx Jose E. Ortiz, Yolanda Sanchez-Palencia, Igor Gutierrez-Zugasti, Trinidad Torres, Manuel Gonzalez-Morales2018Protein diagenesis in archaeological gastropod shells and the suitability of this material for amino acid racemisation dating: Phorcus lineatus (da Costa, 1778)Quaternary Geochronology4616-2710.1016/j.quageo.2018.02.002https://www.sciencedirect.com/science/article/pii/S1871101417300663 START YEAR: 23000 cal yr BP * END YEAR: 0 cal yr BP -5.1 43.3 -3.4 43.5