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Amino acid geochronology of the type Cromerian of West Runton, Norfolk, UK.

Penkman KE, Preece RC, Keen DH, Collins MJ - Quat Int (2010)

Bottom Line: Two genera of freshwater gastropods (Valvata and Bithynia) are used to explore the value of using multiple amino acids from the intra-crystalline fraction, which should be more protected from the effects of diagenesis than the inter-crystalline component.In order to put the amino acid data from the West Runton Freshwater Bed into perspective, statistical analyses are used to compare them with results from the Hoxnian (MIS 11) site at Clacton-on-Sea, Essex.The data are also compared with results from Waverley Wood, an important archaeological site in the English Midlands falling within the 'Cromerian Complex'.

View Article: PubMed Central - PubMed

Affiliation: BioArCh, Dept of Chemistry, University of York, York YO10 5DD, United Kingdom.

ABSTRACT
Aminostratigraphic studies of continental deposits in the UK have hitherto relied almost exclusively on data from the aragonitic shells of non-marine molluscs for dating Pleistocene sequences. This is usually based on the d/l value of a single amino acid, d-alloisoleucine/l-isoleucine (A/I), in the total shell proteins. Two genera of freshwater gastropods (Valvata and Bithynia) are used to explore the value of using multiple amino acids from the intra-crystalline fraction, which should be more protected from the effects of diagenesis than the inter-crystalline component. Results are compared from both the aragonitic shells and opercula composed of calcite, a more stable form of calcium carbonate. In order to put the amino acid data from the West Runton Freshwater Bed into perspective, statistical analyses are used to compare them with results from the Hoxnian (MIS 11) site at Clacton-on-Sea, Essex. Twelve protein decomposition indicators revealed that the results from the shells were not as clear-cut as those from the opercula. Five indicators from the Valvata shell suggest that West Runton is older than Clacton (at a 95% significance level), but two actually suggested a younger age. Seven indicators show that the Bithynia shells from West Runton are older than congeneric shells from Clacton. In marked contrast, all 12 indicators isolated from the opercula demonstrate that West Runton is significantly older than Clacton. The data are also compared with results from Waverley Wood, an important archaeological site in the English Midlands falling within the 'Cromerian Complex'. Contrary to earlier interpretations, the new amino acid data from Bithynia opercula indicate that West Runton is older than Waverley Wood, a relationship now consistent with the available biostratigraphy.

No MeSH data available.


Related in: MedlinePlus

THAA vs FAA for Asx, Glx, Ala and Val d/l in the bleached (intra-crystalline) fraction of Bithynia opercula from Clacton, Waverley Wood, West Runton and Pakefield. Plotting the extent of racemization of THAA against FAA presents the samples in relative aminostratigraphical order based on their d/ls, with more degraded samples having higher values of d/ls for both the FAA and THAA fractions. Error bars for the Clacton and Waverley Wood data represent two standard deviations about the mean for multiple individual samples. The low concentrations from the small Pakefield opercula result in an increase in variability, particularly in Glx and Val. However, the Pakefield opercula are more racemised than those from Waverley Wood, but show similar levels of protein decomposition to samples from West Runton.
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fig3: THAA vs FAA for Asx, Glx, Ala and Val d/l in the bleached (intra-crystalline) fraction of Bithynia opercula from Clacton, Waverley Wood, West Runton and Pakefield. Plotting the extent of racemization of THAA against FAA presents the samples in relative aminostratigraphical order based on their d/ls, with more degraded samples having higher values of d/ls for both the FAA and THAA fractions. Error bars for the Clacton and Waverley Wood data represent two standard deviations about the mean for multiple individual samples. The low concentrations from the small Pakefield opercula result in an increase in variability, particularly in Glx and Val. However, the Pakefield opercula are more racemised than those from Waverley Wood, but show similar levels of protein decomposition to samples from West Runton.


Amino acid geochronology of the type Cromerian of West Runton, Norfolk, UK.

Penkman KE, Preece RC, Keen DH, Collins MJ - Quat Int (2010)

THAA vs FAA for Asx, Glx, Ala and Val d/l in the bleached (intra-crystalline) fraction of Bithynia opercula from Clacton, Waverley Wood, West Runton and Pakefield. Plotting the extent of racemization of THAA against FAA presents the samples in relative aminostratigraphical order based on their d/ls, with more degraded samples having higher values of d/ls for both the FAA and THAA fractions. Error bars for the Clacton and Waverley Wood data represent two standard deviations about the mean for multiple individual samples. The low concentrations from the small Pakefield opercula result in an increase in variability, particularly in Glx and Val. However, the Pakefield opercula are more racemised than those from Waverley Wood, but show similar levels of protein decomposition to samples from West Runton.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2991590&req=5

fig3: THAA vs FAA for Asx, Glx, Ala and Val d/l in the bleached (intra-crystalline) fraction of Bithynia opercula from Clacton, Waverley Wood, West Runton and Pakefield. Plotting the extent of racemization of THAA against FAA presents the samples in relative aminostratigraphical order based on their d/ls, with more degraded samples having higher values of d/ls for both the FAA and THAA fractions. Error bars for the Clacton and Waverley Wood data represent two standard deviations about the mean for multiple individual samples. The low concentrations from the small Pakefield opercula result in an increase in variability, particularly in Glx and Val. However, the Pakefield opercula are more racemised than those from Waverley Wood, but show similar levels of protein decomposition to samples from West Runton.
Bottom Line: Two genera of freshwater gastropods (Valvata and Bithynia) are used to explore the value of using multiple amino acids from the intra-crystalline fraction, which should be more protected from the effects of diagenesis than the inter-crystalline component.In order to put the amino acid data from the West Runton Freshwater Bed into perspective, statistical analyses are used to compare them with results from the Hoxnian (MIS 11) site at Clacton-on-Sea, Essex.The data are also compared with results from Waverley Wood, an important archaeological site in the English Midlands falling within the 'Cromerian Complex'.

View Article: PubMed Central - PubMed

Affiliation: BioArCh, Dept of Chemistry, University of York, York YO10 5DD, United Kingdom.

ABSTRACT
Aminostratigraphic studies of continental deposits in the UK have hitherto relied almost exclusively on data from the aragonitic shells of non-marine molluscs for dating Pleistocene sequences. This is usually based on the d/l value of a single amino acid, d-alloisoleucine/l-isoleucine (A/I), in the total shell proteins. Two genera of freshwater gastropods (Valvata and Bithynia) are used to explore the value of using multiple amino acids from the intra-crystalline fraction, which should be more protected from the effects of diagenesis than the inter-crystalline component. Results are compared from both the aragonitic shells and opercula composed of calcite, a more stable form of calcium carbonate. In order to put the amino acid data from the West Runton Freshwater Bed into perspective, statistical analyses are used to compare them with results from the Hoxnian (MIS 11) site at Clacton-on-Sea, Essex. Twelve protein decomposition indicators revealed that the results from the shells were not as clear-cut as those from the opercula. Five indicators from the Valvata shell suggest that West Runton is older than Clacton (at a 95% significance level), but two actually suggested a younger age. Seven indicators show that the Bithynia shells from West Runton are older than congeneric shells from Clacton. In marked contrast, all 12 indicators isolated from the opercula demonstrate that West Runton is significantly older than Clacton. The data are also compared with results from Waverley Wood, an important archaeological site in the English Midlands falling within the 'Cromerian Complex'. Contrary to earlier interpretations, the new amino acid data from Bithynia opercula indicate that West Runton is older than Waverley Wood, a relationship now consistent with the available biostratigraphy.

No MeSH data available.


Related in: MedlinePlus