John F Wehmiller
Biographic Data
| ID | 4129169 |
|---|---|
| NAME | John F Wehmiller |
| GIVEN NAMES | John F |
| FAMILY NAME | Wehmiller |
| SIGNATURE | WEHMILLER J F |
| AFFILIATIONS | University of Delaware |
| ORCID | 0000-0001-6967-5274 |
| VERIFIED | Yes |
| TOTAL WORKS | 12 |
| TOTAL CITATIONS | 0 |
| WORKS AS AUTHOR | 12 |
| WORKS AS EDITOR | 0 |
| FIRST PUBLICATION YEAR | 1978 |
| LATEST PUBLICATION YEAR | 2012 |
| H-INDEX | 0 |
Calibration of amino acid racemization (AAR) kinetics in U. S. Atlantic Coastal Plain Quaternary mollusks using 87/86Sr analyses
Quaternary depositional patterns and sea-level fluctuations, Northeastern North Carolina
A detailed record of late Quaternary sea-level oscillations is preserved within the upper 45 m of deposits along an eight km transect across Croatan Sound, a drowned tributary of the Roanoke/Albemarle drainage system, northeastern North Carolina. Drill-hole and seismic data reveal nine relatively complete sequences filling an antecedent valley comprised of discontinuous middle and early Pleistocene deposits. On interfluves, lithologically similar…
Aspartic acid racemization dating of Holocene brachiopods and bivalves from the southern Brazilian shelf, South Atlantic
The extent of racemization of aspartic acid (Asp) has been used to estimate the ages of 9 shells of the epifaunal calcitic brachiopod Bouchardia rosea and 9 shells of the infaunal aragonitic bivalve Semele casali . Both taxa were collected concurrently from the same sites at depths of 10 m and 30 m off the coast of Brazil. Asp D/L values show an excellent correlation with radiocarbon age at both sites and for both taxa ( r 2 Site 9 B. rosea = 0.9…
Uranium-series coral ages from the US Atlantic Coastal Plain–the “80ka problem” revisited
Seismic-Reflection Identification of Susquehanna River Paleochannels on the Mid-Atlantic Coastal Plain
Land-based, high-resolution seismic-reflection methods were used to image Quaternary paleochannels of the Susquehanna River system. Using a portable, 12-channel signal-enhancing seismograph, 12 accelerometers as receivers, and a 4.54-kg sledge hammer struck against an aluminum plate as a source, a sixfold, multichannel seismic profile 2.5 km long was acquired at Taylors Island, Maryland. On the processed seismic profile, pronounced high-amplitude…
Low uplift rates and terrace reoccupation inferred from mollusk aminostratigraphy, Coquimbo Bay area, Chile
Mollusk aminostratigraphy of Quaternary marine terrace sediments at Coquimbo Bay, Chile, combined with recently available electron spin resonance (ESR) ages, necessitates revision of the northern Chilean relative sea-level and terrace chronology. Protothaca and Muliniad-alloisoleucine/l-isoleucine values define four aminozones which are consistent with available ESR ages. Terrace reoccupation during successive high sea-level stands is inferred on…
Theoretical Correlations and Lateral Discontinuities in the Quaternary Aminostratigraphic Record of the U.S. Atlantic Coastal Plain
Aminostratigraphic correlations of emergent Quaternary deposits along the U.S. Atlantic Coastal Plain have employed independent radiometric data, regional temperature history models, and assumptions regarding the nature of the preserved late Quaternary sea-level record on this passive margin. A substantial “aminostratigraphic offset” is required if regional aminozones are rigorously constrained by all available Th/U data. New insights regarding t…
Interlaboratory Comparison of Amino Acid Enantiomeric Ratios in Fossil Pleistocene Mollusks
Enantiomeric (d/l) ratios of eight amino acids in three homogeneous powdered fossil Pleistocene mollusk samples have been compared. Eleven laboratories have contributed results to this effort. Three gas chromatographic methods and one ion-exchange chromatographic method were used. In general, the coefficients of variation (c.v.) are best for alanine, glutamic acid, and aspartic acid (3–8%). For leucine and phenylalanine, the c.v.'s are between 5 …
Amino Acid Age Estimates, Quaternary Atlantic Coastal Plain
Amino acid enantiomeric (D/L) ratios in the mollusk Mercenaria are compared with recently published biostratigraphic and/or U-series solitary coral data from 22 Quaternary localities on the central and southern Atlantic Coastal Plain. In all cases, local relative aminostratigraphic sequences are consistent with relative ages inferred from U-series or biostratigraphic data, although occasionally more depositional events are recognized by aminostra…
Comparison of Amino Acid Racemization Geochronometry with Lithostratigraphy, Biostratigraphy, Uranium-Series Coral Dating, and Magnetostratigraphy in the Atlantic Coastal Plain of the Southeastern Uni…
The results of an integrated study comprising litho- and biostratigraphic investigations, uranium-series coral dating, amino acid racemization in molluscs, and paleomagnetic measurements are compared to ascertain relative and absolute ages of Pleistocene deposits of the Atlantic Coastal Plain in North and South Carolina. Four depositional events are inferred for South Carolina and two for North Carolina by all methods. The data suggest that there…
Stratigraphy of Late Quaternary Estuarine Deposits and Amino Acid Stereochemistry of Oyster Shells Beneath San Francisco Bay, California
The sequence of Quaternary deposits beneath the floor of San Francisco Bay includes four to seven noncontemporaneous estuarine units intercalated with alluvium and dune sand. Units L (0–10,000 B.P.), M (>40,000 B.P., probably ca. 80,000–140,000 B.P.), and N (older than unit M) are distinctly superposed. The dominant molluscan fossil in each of these three units is Ostrea lurida Carpenter, the native oyster along much of the pacific Coast of North…
Alternative Kinetic Models for the Interpretation of Amino Acid Enantiomeric ratios in Pleistocene Mollusks
Alternative kinetic models for amino acid racemization in Pleistocene molluscan samples are compared by examination of results for samples from marine Pleistocene deposits in California, Washington, and Florida. Linear kinetic models previously have been applied to the Florida samples [ Mitterer, R.M. (1975). Earth and Planetary Science Letters 28 , 275–282.] because these kinetics were observed in laboratory pyrolysis experiments with the partic…
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Alternative Kinetic Models for the Interpretation of Amino Acid Enantiomeric ratios in Pleistocene Mollusks
Alternative kinetic models for amino acid racemization in Pleistocene molluscan samples are compared by examination of results for samples from marine Pleistocene deposits in California, Washington, and Florida. Linear kinetic models previously have been applied to the Florida samples [ Mitterer, R.M. (1975). Earth and Planetary Science Letters 28 , 275–282.] because these kinetics were observed in laboratory pyrolysis experiments with the partic…
Stratigraphy of Late Quaternary Estuarine Deposits and Amino Acid Stereochemistry of Oyster Shells Beneath San Francisco Bay, California
The sequence of Quaternary deposits beneath the floor of San Francisco Bay includes four to seven noncontemporaneous estuarine units intercalated with alluvium and dune sand. Units L (0–10,000 B.P.), M (>40,000 B.P., probably ca. 80,000–140,000 B.P.), and N (older than unit M) are distinctly superposed. The dominant molluscan fossil in each of these three units is Ostrea lurida Carpenter, the native oyster along much of the pacific Coast of North…
Amino Acid Age Estimates, Quaternary Atlantic Coastal Plain
Amino acid enantiomeric (D/L) ratios in the mollusk Mercenaria are compared with recently published biostratigraphic and/or U-series solitary coral data from 22 Quaternary localities on the central and southern Atlantic Coastal Plain. In all cases, local relative aminostratigraphic sequences are consistent with relative ages inferred from U-series or biostratigraphic data, although occasionally more depositional events are recognized by aminostra…
Comparison of Amino Acid Racemization Geochronometry with Lithostratigraphy, Biostratigraphy, Uranium-Series Coral Dating, and Magnetostratigraphy in the Atlantic Coastal Plain of the Southeastern Uni…
The results of an integrated study comprising litho- and biostratigraphic investigations, uranium-series coral dating, amino acid racemization in molluscs, and paleomagnetic measurements are compared to ascertain relative and absolute ages of Pleistocene deposits of the Atlantic Coastal Plain in North and South Carolina. Four depositional events are inferred for South Carolina and two for North Carolina by all methods. The data suggest that there…
Interlaboratory Comparison of Amino Acid Enantiomeric Ratios in Fossil Pleistocene Mollusks
Enantiomeric (d/l) ratios of eight amino acids in three homogeneous powdered fossil Pleistocene mollusk samples have been compared. Eleven laboratories have contributed results to this effort. Three gas chromatographic methods and one ion-exchange chromatographic method were used. In general, the coefficients of variation (c.v.) are best for alanine, glutamic acid, and aspartic acid (3–8%). For leucine and phenylalanine, the c.v.'s are between 5 …
Low uplift rates and terrace reoccupation inferred from mollusk aminostratigraphy, Coquimbo Bay area, Chile
Mollusk aminostratigraphy of Quaternary marine terrace sediments at Coquimbo Bay, Chile, combined with recently available electron spin resonance (ESR) ages, necessitates revision of the northern Chilean relative sea-level and terrace chronology. Protothaca and Muliniad-alloisoleucine/l-isoleucine values define four aminozones which are consistent with available ESR ages. Terrace reoccupation during successive high sea-level stands is inferred on…
Theoretical Correlations and Lateral Discontinuities in the Quaternary Aminostratigraphic Record of the U.S. Atlantic Coastal Plain
Aminostratigraphic correlations of emergent Quaternary deposits along the U.S. Atlantic Coastal Plain have employed independent radiometric data, regional temperature history models, and assumptions regarding the nature of the preserved late Quaternary sea-level record on this passive margin. A substantial “aminostratigraphic offset” is required if regional aminozones are rigorously constrained by all available Th/U data. New insights regarding t…
Seismic-Reflection Identification of Susquehanna River Paleochannels on the Mid-Atlantic Coastal Plain
Land-based, high-resolution seismic-reflection methods were used to image Quaternary paleochannels of the Susquehanna River system. Using a portable, 12-channel signal-enhancing seismograph, 12 accelerometers as receivers, and a 4.54-kg sledge hammer struck against an aluminum plate as a source, a sixfold, multichannel seismic profile 2.5 km long was acquired at Taylors Island, Maryland. On the processed seismic profile, pronounced high-amplitude…
Uranium-series coral ages from the US Atlantic Coastal Plain–the “80ka problem” revisited
Aspartic acid racemization dating of Holocene brachiopods and bivalves from the southern Brazilian shelf, South Atlantic
The extent of racemization of aspartic acid (Asp) has been used to estimate the ages of 9 shells of the epifaunal calcitic brachiopod Bouchardia rosea and 9 shells of the infaunal aragonitic bivalve Semele casali . Both taxa were collected concurrently from the same sites at depths of 10 m and 30 m off the coast of Brazil. Asp D/L values show an excellent correlation with radiocarbon age at both sites and for both taxa ( r 2 Site 9 B. rosea = 0.9…
Quaternary depositional patterns and sea-level fluctuations, Northeastern North Carolina
A detailed record of late Quaternary sea-level oscillations is preserved within the upper 45 m of deposits along an eight km transect across Croatan Sound, a drowned tributary of the Roanoke/Albemarle drainage system, northeastern North Carolina. Drill-hole and seismic data reveal nine relatively complete sequences filling an antecedent valley comprised of discontinuous middle and early Pleistocene deposits. On interfluves, lithologically similar…
Calibration of amino acid racemization (AAR) kinetics in U. S. Atlantic Coastal Plain Quaternary mollusks using 87/86Sr analyses
Geology (10 works) · Geology and Paleoclimatology Research (9 works) · Paleontology (9 works) · Isotope Analysis in Ecology (7 works) · Oceanography (7 works) · Quaternary (6 works) · Coastal plain (5 works) · Pleistocene (5 works) · Marine Biology and Ecology Research (4 works) · Sea level (4 works)