Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 1991
Whereas the presence of amino acids in fossil materials is clearly related to biosynthesis, an in... more Whereas the presence of amino acids in fossil materials is clearly related to biosynthesis, an indigenous relationship with the fossil may be suspect. At present, attempts to establish the indigeneity of amino acids in fossils are based on distribution and stereochemistry. However, fossil systems are not closed and racemization may be retarded in organic materials within a fossil matrix. The advent of new technologies has resulted in alternative methods for evaluating the authenticity of fossil organic matter. A comparison of the stable carbon isotope compositions of the D- and L-enantiomers of individual amino acids facilitates the evaluation of indigeneity. Here we report the application of this method for determining the origin(s) of amino acids in fossils and extraterrestrial samples. Further, nitrogen isotope compositions of fossil materials should reflect trophic order, with increasing enrichment in 515N with progression up the food chain. Establishment of the trophic position...
Results of an analysis of amino acids and hydrocarbons found in the Isua banded iron formation, w... more Results of an analysis of amino acids and hydrocarbons found in the Isua banded iron formation, which contains the oldest known rocks on earth, are discussed. Similarities are pointed out between the relative amino acid abundances of the Isua rocks and those of lichens found on their surfaces, and a lack of substantial racemization indicated by the low D/L ratios in the 3800-million year old rock samples is noted. Experimental results showing the possibility of amino acid diffusion from lichens into the rocks are presented. Comparisons of the Isua rock amino acid D/L ratios with those reported for samples from other regions indicates that none of the Isua amino acids are older than a few tens of thousands to a few hundred thousand years. Analyses of the saturated hydrocarbons of the Isua samples reveals no odd carbon number preference, which may indicate antiquity, however laboratory experiments have shown that amino acids and aromatic and saturated aliphatic hydrocarbons could not ...
... [36] Elmore, RD and Crawford, L., “Remanence in authigenic magnetite: Testing the hydrocarbon... more ... [36] Elmore, RD and Crawford, L., “Remanence in authigenic magnetite: Testing the hydrocarbon-magnetite hypothesis,” J. Geophysical Research invited paper for special section on Magnetization Processes in Sediments, 95, 4539-4549 (1990). ...
A paleomagnetic study of red fault-related breccia veins in the Cambro-Ordovician Durness Group i... more A paleomagnetic study of red fault-related breccia veins in the Cambro-Ordovician Durness Group in NW Scotland was conducted to determine the time of brecciation, the origin of the veins, and the nature and timing of associated fluid-related diagenetic alteration. The ...
American Association of Petroleum Geologists eBooks, 1990
The middle Proterozoic Nonesuch Formation is part of a transgressive-regressive sequence that fil... more The middle Proterozoic Nonesuch Formation is part of a transgressive-regressive sequence that fills the Keweenawan trough in northern Michigan (Upper Peninsula) and northern Wisconsin. The Nonesuch is conformable with the underlying Copper Harbor Conglomerate (alluvial) and overlying Freda Sandstone (fluvial). Based on integration of outcrop and core data, three genetic facies assemblages have been recognized. A marginal-lacustrine assemblage, characterized by interbedded sandstone, siltstone, mudstone, and sandstone/shale couplets, represents deposition on a sandflat/mudflat complex. A lacustrine assemblage is characterized by massive to well-laminated, dark shaly siltstone, carbonate laminites, shale, siltstone, and mudstone. These sediments were deposited in a progress vely shallowing perennial lake that periodically may have been thermally stratified. A gradual transition from a lacustrine environment to a fluvial environment is represented by red, horizontally laminated and rippled, fine-grained sandstone and siltstone of the fluvial-lacustrine assemblage. Interactions among subsidence rates, sedimentation rates, lake-level fluctuations, and possible climatic changes have resulted in variable vertical facies sequences. Total organic carbon analyses show a strong correlation between organic richness and the shale facies (lacustrine assemblage) and parts of the marginal-lacustrine assemblage. Quantitative assessment of organic-carbon levels for the shale facies reveals the presence of organic-prone lithologies (average >0.50% TOC) comprising at least 50% of five of the eight core sections considered. Organic petrographic and geochemical analyses of selected samples, including incident white light and reflected blue-light fluorescent microscopy, pyrolysis-flame ionization detection, Rock-Eval pyrolysis, and pyrolysis-gas chromatography-mass spectrometry, indicate that most kerogens may be classified as type I and/or type II. A type III designation for some specimens is suggested based on pyrolysis r sults. Distinct petrographic and geochemical characteristics among these samples, viewed in terms of geographic and stratigraphic distribution, may be interpreted as the result of differential preservation of similar source organic materials rather than differential incorporation of source materials or varying thermal maturation histories within the basin. Consideration of all petrographic and geochemical data suggests that limited intervals of the Nonesuch Formation qualify as moderate to good hydrocarbon source rocks that have experienced a mild thermal history (i.e., "oil window" thermal regime). Successful hydrocarbon exploration efforts in the Mid-Continent rift system will depend on how well one can correlate the presence of better source rocks with identification of suitable reservoir rocks and trapping mechanisms. Given the antiquity of these rocks, however, details about timing of hydrocarbon migration and accumulation and preservation of reservoirs also must be addressed. End_Page 197------------------------
Ship timbers were discovered during the excavation of the Islamic site of al-Balīd recycled in th... more Ship timbers were discovered during the excavation of the Islamic site of al-Balīd recycled in the buildings of its citadel and the Great Mosque. These fragments stripped from the hulls of Indian Ocean medieval sewn vessels form the largest collection of archaeological evidence for the ships sailing during the Middle Islamic Period (10th–15th century CE). More than one third of the timbers bears traces of a bitumen mixture used as luting and coating to seal the ships planking to waterproof and protect their hulls, a practice generally associated with sewn-plank construction. This paper presents the result of the GC-MS, carbon and hydrogen isotope on chromatographic fractions, and X-Ray diffraction analyses on twenty-two samples of the luting extracted from fifteen timbers from al-Balīd. The nature of the constituents of the amalgam is determined showing that the luting consists of bitumen mixed with mineral matter, fat or oil and two triterpenic resins, dammar (Dipterocarpacea) and frankincense. The chemical signature of the bitumen indicates that it was likely sourced from two seeps in southwest Iranian: Mamatain and Ain Gir-Chersch Mehrgir-Dehluran. The origin of the bitumen might suggest that the luting was applied during the construction or repairing of Indian Ocean vessels in boatyards along the coasts of the Arabian/Persian Gulf or Southern and Eastern Arabia.
Twelve samples of organic mixtures collected from floors and potsherds in different areas of Kuri... more Twelve samples of organic mixtures collected from floors and potsherds in different areas of Kuriki Höyük (SE Turkey) were analyzed by geochemical techniques to identify bitumens and try to locate their sources. Oil seeps from the region (Gercüş, Badzivan, Zengen, Kerbent, Kayatepe, Eruh) and some other samples characterized later as asphaltites (Kumçati, Anittepe, Silip), were compared to the archaeological mixtures. To trace the source of bitumen, stable carbon isotope values of chromatographic fractions and mass fragmentograms of steranes and terpanes were acquired on both archaeological mixtures and oil seeps used as references. Bitumen was recognized in all samples and the Kerbent oil seep is the most likely source of bitumen at Kuriki Höyük. This source was used from 4000 BCE to 200 CE. In contrast, Eruh appears to be the likely source for the other archaeological sites of the neighbourhood namely: Kavuşan Höyük, Salat Tepe and Hakemi Use. The mineral composition of archaeological samples shows that the mixtures used at Kuriki Höyük are similar to those observed elsewhere in many archaeological bitumens from other localities.
In August 2013, we observed a high incidence (44%) of synchronous fault bars across the rectrices... more In August 2013, we observed a high incidence (44%) of synchronous fault bars across the rectrices of juvenile Grasshopper Sparrows (Ammodrammus savannarum) captured near El Reno, Oklahoma. Earlier that year, on May 31, the site was struck by a severe storm which rained hailstones exceeding 5.5 cm diameter and spawned an historic 4.2 km-wide tornado <8 km to the south of the site. An assessment of Grasshopper Sparrow nesting phenology indicated that a large number of nestlings were likely growing tail feathers when the storm hit. To assess the nature of the fault bars, we measured δ15N and δ13C stable isotope ratios within four 0.25-0.40 mg feather sections taken from the distal end of a tail feather from 18 juveniles captured at the site in August. The fault bar, if present, was contained within only one section. Fault bars were located at various positions on the distal half of feathers, and fault bar width significantly increased as a function of distance from the tip (i.e., ag...
The objective of this study is to test models for the origin of widespread remagnetizations in th... more The objective of this study is to test models for the origin of widespread remagnetizations in the Mississippian Deseret Limestone. The Delle Phosphatic Member of the Deseret Limestone is a source rock for hydrocarbons in Utah. Based on modeling studies it entered the oil window in the early Cretaceous during the Sevier orogeny. Paleomagnetic results from central and western Utah indicate that the unit contains two ancient magnetizations. Based on low burial temperatures, these are interpreted to be chemical remanent magnetizations (CRMs). The demagnetization characteristics and rock magnetic studies indicate that the CRMs reside in magnetite. Three fold tests from western Utah indicate the presence of a pre-folding Triassic to Jurassic CRM with dual polarities. Preliminary isotopic results suggest that the rocks that contain this CRM in western Utah are unaltered. The age of the CRM is just prior to the modeled time for organic matter maturation in the unit. This CRM is interpreted...
The thrust of this study is to test the hypothesized connection between magnetite authigenesis an... more The thrust of this study is to test the hypothesized connection between magnetite authigenesis and diagenetic reactions forming illite, an idea based on the results of paleomagnetic, rock magnetic, geochemical, and petrographic/SEM studies on Jurassic sedimentary rocks of Skye, Scotland. The Jurassic rocks in southern Skye contain a dual polarity magnetization residing in magnetite that is interpreted as a chemical
Widespread chemical remanent magnetizations (CRMs) are common in sedimentary rocks and several me... more Widespread chemical remanent magnetizations (CRMs) are common in sedimentary rocks and several mechanisms such as the migration of orogenic fluids and the presence of hydrocarbons have been proposed to cause their formation. Another possible mechanism causing magnetite authigenesis and CRMs is the low temperature diagenetic conversion of smectite to illite during burial in sedimentary rocks. Although empirical evidence supports such
1School of Geology and Geophysics, University of Oklahoma, Norman, OK 73019, USA 2Department of G... more 1School of Geology and Geophysics, University of Oklahoma, Norman, OK 73019, USA 2Department of Geology and Petroleum Geology, University of Aberdeen, King's College, Aberdeen, AB24 3UE, UK ... The Lewisian basement rock in NW Scotland contains sandstone dykes that ...
Proceedings of the National Academy of Sciences, 1980
alpha-Melanocyte-stimulating hormone (alpha-MSH) reversibly darkens frog skins by stimulating mel... more alpha-Melanocyte-stimulating hormone (alpha-MSH) reversibly darkens frog skins by stimulating melanosome movement (dispersion) within melanophores. Heat-alkali treatment of alpha-MSH results in prolonged biological activity of the hormone. Quantitative gas chromatographic analysis of the hydrolyzed heat-alkali-treated peptide revealed partial racemization particularly at the 4(methionine) and 7(phenylalanine) positions. [Nle4]-alpha-MSH, a synthetic analogue of alpha-MSH, reversibly darkens frog skins and also exhibits prolonged activity after heat-alkali treatment. Synthesis of [Nle4, D-Phe7]-alpha-MSH provided an analogue with prolonged biological activity identical to that observed with heat-alkali-treated alpha-MSH or [Nle4]-alpha-MSH. [Nle4, D-Phe7]-alpha-MSH was resistant to enzymatic degradation by serum enzymes. In addition, this peptide exhibited dramatically increased biological activity as determined by frog skin bioassay, activation of mouse melanoma adenylate cyclase, a...
Physics and Chemistry of the Earth, Parts A/B/C, 2002
Although the migration of fluids is a likely agent of remagnetization for some chemical remanent ... more Although the migration of fluids is a likely agent of remagnetization for some chemical remanent magnetizations (CRMs), widespread CRMs, which occur in rocks that have not been altered by externally derived fluids, need to explained by another mechanism. We are testing clay ...
Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 1991
Whereas the presence of amino acids in fossil materials is clearly related to biosynthesis, an in... more Whereas the presence of amino acids in fossil materials is clearly related to biosynthesis, an indigenous relationship with the fossil may be suspect. At present, attempts to establish the indigeneity of amino acids in fossils are based on distribution and stereochemistry. However, fossil systems are not closed and racemization may be retarded in organic materials within a fossil matrix. The advent of new technologies has resulted in alternative methods for evaluating the authenticity of fossil organic matter. A comparison of the stable carbon isotope compositions of the D- and L-enantiomers of individual amino acids facilitates the evaluation of indigeneity. Here we report the application of this method for determining the origin(s) of amino acids in fossils and extraterrestrial samples. Further, nitrogen isotope compositions of fossil materials should reflect trophic order, with increasing enrichment in 515N with progression up the food chain. Establishment of the trophic position...
Results of an analysis of amino acids and hydrocarbons found in the Isua banded iron formation, w... more Results of an analysis of amino acids and hydrocarbons found in the Isua banded iron formation, which contains the oldest known rocks on earth, are discussed. Similarities are pointed out between the relative amino acid abundances of the Isua rocks and those of lichens found on their surfaces, and a lack of substantial racemization indicated by the low D/L ratios in the 3800-million year old rock samples is noted. Experimental results showing the possibility of amino acid diffusion from lichens into the rocks are presented. Comparisons of the Isua rock amino acid D/L ratios with those reported for samples from other regions indicates that none of the Isua amino acids are older than a few tens of thousands to a few hundred thousand years. Analyses of the saturated hydrocarbons of the Isua samples reveals no odd carbon number preference, which may indicate antiquity, however laboratory experiments have shown that amino acids and aromatic and saturated aliphatic hydrocarbons could not ...
... [36] Elmore, RD and Crawford, L., “Remanence in authigenic magnetite: Testing the hydrocarbon... more ... [36] Elmore, RD and Crawford, L., “Remanence in authigenic magnetite: Testing the hydrocarbon-magnetite hypothesis,” J. Geophysical Research invited paper for special section on Magnetization Processes in Sediments, 95, 4539-4549 (1990). ...
A paleomagnetic study of red fault-related breccia veins in the Cambro-Ordovician Durness Group i... more A paleomagnetic study of red fault-related breccia veins in the Cambro-Ordovician Durness Group in NW Scotland was conducted to determine the time of brecciation, the origin of the veins, and the nature and timing of associated fluid-related diagenetic alteration. The ...
American Association of Petroleum Geologists eBooks, 1990
The middle Proterozoic Nonesuch Formation is part of a transgressive-regressive sequence that fil... more The middle Proterozoic Nonesuch Formation is part of a transgressive-regressive sequence that fills the Keweenawan trough in northern Michigan (Upper Peninsula) and northern Wisconsin. The Nonesuch is conformable with the underlying Copper Harbor Conglomerate (alluvial) and overlying Freda Sandstone (fluvial). Based on integration of outcrop and core data, three genetic facies assemblages have been recognized. A marginal-lacustrine assemblage, characterized by interbedded sandstone, siltstone, mudstone, and sandstone/shale couplets, represents deposition on a sandflat/mudflat complex. A lacustrine assemblage is characterized by massive to well-laminated, dark shaly siltstone, carbonate laminites, shale, siltstone, and mudstone. These sediments were deposited in a progress vely shallowing perennial lake that periodically may have been thermally stratified. A gradual transition from a lacustrine environment to a fluvial environment is represented by red, horizontally laminated and rippled, fine-grained sandstone and siltstone of the fluvial-lacustrine assemblage. Interactions among subsidence rates, sedimentation rates, lake-level fluctuations, and possible climatic changes have resulted in variable vertical facies sequences. Total organic carbon analyses show a strong correlation between organic richness and the shale facies (lacustrine assemblage) and parts of the marginal-lacustrine assemblage. Quantitative assessment of organic-carbon levels for the shale facies reveals the presence of organic-prone lithologies (average >0.50% TOC) comprising at least 50% of five of the eight core sections considered. Organic petrographic and geochemical analyses of selected samples, including incident white light and reflected blue-light fluorescent microscopy, pyrolysis-flame ionization detection, Rock-Eval pyrolysis, and pyrolysis-gas chromatography-mass spectrometry, indicate that most kerogens may be classified as type I and/or type II. A type III designation for some specimens is suggested based on pyrolysis r sults. Distinct petrographic and geochemical characteristics among these samples, viewed in terms of geographic and stratigraphic distribution, may be interpreted as the result of differential preservation of similar source organic materials rather than differential incorporation of source materials or varying thermal maturation histories within the basin. Consideration of all petrographic and geochemical data suggests that limited intervals of the Nonesuch Formation qualify as moderate to good hydrocarbon source rocks that have experienced a mild thermal history (i.e., "oil window" thermal regime). Successful hydrocarbon exploration efforts in the Mid-Continent rift system will depend on how well one can correlate the presence of better source rocks with identification of suitable reservoir rocks and trapping mechanisms. Given the antiquity of these rocks, however, details about timing of hydrocarbon migration and accumulation and preservation of reservoirs also must be addressed. End_Page 197------------------------
Ship timbers were discovered during the excavation of the Islamic site of al-Balīd recycled in th... more Ship timbers were discovered during the excavation of the Islamic site of al-Balīd recycled in the buildings of its citadel and the Great Mosque. These fragments stripped from the hulls of Indian Ocean medieval sewn vessels form the largest collection of archaeological evidence for the ships sailing during the Middle Islamic Period (10th–15th century CE). More than one third of the timbers bears traces of a bitumen mixture used as luting and coating to seal the ships planking to waterproof and protect their hulls, a practice generally associated with sewn-plank construction. This paper presents the result of the GC-MS, carbon and hydrogen isotope on chromatographic fractions, and X-Ray diffraction analyses on twenty-two samples of the luting extracted from fifteen timbers from al-Balīd. The nature of the constituents of the amalgam is determined showing that the luting consists of bitumen mixed with mineral matter, fat or oil and two triterpenic resins, dammar (Dipterocarpacea) and frankincense. The chemical signature of the bitumen indicates that it was likely sourced from two seeps in southwest Iranian: Mamatain and Ain Gir-Chersch Mehrgir-Dehluran. The origin of the bitumen might suggest that the luting was applied during the construction or repairing of Indian Ocean vessels in boatyards along the coasts of the Arabian/Persian Gulf or Southern and Eastern Arabia.
Twelve samples of organic mixtures collected from floors and potsherds in different areas of Kuri... more Twelve samples of organic mixtures collected from floors and potsherds in different areas of Kuriki Höyük (SE Turkey) were analyzed by geochemical techniques to identify bitumens and try to locate their sources. Oil seeps from the region (Gercüş, Badzivan, Zengen, Kerbent, Kayatepe, Eruh) and some other samples characterized later as asphaltites (Kumçati, Anittepe, Silip), were compared to the archaeological mixtures. To trace the source of bitumen, stable carbon isotope values of chromatographic fractions and mass fragmentograms of steranes and terpanes were acquired on both archaeological mixtures and oil seeps used as references. Bitumen was recognized in all samples and the Kerbent oil seep is the most likely source of bitumen at Kuriki Höyük. This source was used from 4000 BCE to 200 CE. In contrast, Eruh appears to be the likely source for the other archaeological sites of the neighbourhood namely: Kavuşan Höyük, Salat Tepe and Hakemi Use. The mineral composition of archaeological samples shows that the mixtures used at Kuriki Höyük are similar to those observed elsewhere in many archaeological bitumens from other localities.
In August 2013, we observed a high incidence (44%) of synchronous fault bars across the rectrices... more In August 2013, we observed a high incidence (44%) of synchronous fault bars across the rectrices of juvenile Grasshopper Sparrows (Ammodrammus savannarum) captured near El Reno, Oklahoma. Earlier that year, on May 31, the site was struck by a severe storm which rained hailstones exceeding 5.5 cm diameter and spawned an historic 4.2 km-wide tornado <8 km to the south of the site. An assessment of Grasshopper Sparrow nesting phenology indicated that a large number of nestlings were likely growing tail feathers when the storm hit. To assess the nature of the fault bars, we measured δ15N and δ13C stable isotope ratios within four 0.25-0.40 mg feather sections taken from the distal end of a tail feather from 18 juveniles captured at the site in August. The fault bar, if present, was contained within only one section. Fault bars were located at various positions on the distal half of feathers, and fault bar width significantly increased as a function of distance from the tip (i.e., ag...
The objective of this study is to test models for the origin of widespread remagnetizations in th... more The objective of this study is to test models for the origin of widespread remagnetizations in the Mississippian Deseret Limestone. The Delle Phosphatic Member of the Deseret Limestone is a source rock for hydrocarbons in Utah. Based on modeling studies it entered the oil window in the early Cretaceous during the Sevier orogeny. Paleomagnetic results from central and western Utah indicate that the unit contains two ancient magnetizations. Based on low burial temperatures, these are interpreted to be chemical remanent magnetizations (CRMs). The demagnetization characteristics and rock magnetic studies indicate that the CRMs reside in magnetite. Three fold tests from western Utah indicate the presence of a pre-folding Triassic to Jurassic CRM with dual polarities. Preliminary isotopic results suggest that the rocks that contain this CRM in western Utah are unaltered. The age of the CRM is just prior to the modeled time for organic matter maturation in the unit. This CRM is interpreted...
The thrust of this study is to test the hypothesized connection between magnetite authigenesis an... more The thrust of this study is to test the hypothesized connection between magnetite authigenesis and diagenetic reactions forming illite, an idea based on the results of paleomagnetic, rock magnetic, geochemical, and petrographic/SEM studies on Jurassic sedimentary rocks of Skye, Scotland. The Jurassic rocks in southern Skye contain a dual polarity magnetization residing in magnetite that is interpreted as a chemical
Widespread chemical remanent magnetizations (CRMs) are common in sedimentary rocks and several me... more Widespread chemical remanent magnetizations (CRMs) are common in sedimentary rocks and several mechanisms such as the migration of orogenic fluids and the presence of hydrocarbons have been proposed to cause their formation. Another possible mechanism causing magnetite authigenesis and CRMs is the low temperature diagenetic conversion of smectite to illite during burial in sedimentary rocks. Although empirical evidence supports such
1School of Geology and Geophysics, University of Oklahoma, Norman, OK 73019, USA 2Department of G... more 1School of Geology and Geophysics, University of Oklahoma, Norman, OK 73019, USA 2Department of Geology and Petroleum Geology, University of Aberdeen, King's College, Aberdeen, AB24 3UE, UK ... The Lewisian basement rock in NW Scotland contains sandstone dykes that ...
Proceedings of the National Academy of Sciences, 1980
alpha-Melanocyte-stimulating hormone (alpha-MSH) reversibly darkens frog skins by stimulating mel... more alpha-Melanocyte-stimulating hormone (alpha-MSH) reversibly darkens frog skins by stimulating melanosome movement (dispersion) within melanophores. Heat-alkali treatment of alpha-MSH results in prolonged biological activity of the hormone. Quantitative gas chromatographic analysis of the hydrolyzed heat-alkali-treated peptide revealed partial racemization particularly at the 4(methionine) and 7(phenylalanine) positions. [Nle4]-alpha-MSH, a synthetic analogue of alpha-MSH, reversibly darkens frog skins and also exhibits prolonged activity after heat-alkali treatment. Synthesis of [Nle4, D-Phe7]-alpha-MSH provided an analogue with prolonged biological activity identical to that observed with heat-alkali-treated alpha-MSH or [Nle4]-alpha-MSH. [Nle4, D-Phe7]-alpha-MSH was resistant to enzymatic degradation by serum enzymes. In addition, this peptide exhibited dramatically increased biological activity as determined by frog skin bioassay, activation of mouse melanoma adenylate cyclase, a...
Physics and Chemistry of the Earth, Parts A/B/C, 2002
Although the migration of fluids is a likely agent of remagnetization for some chemical remanent ... more Although the migration of fluids is a likely agent of remagnetization for some chemical remanent magnetizations (CRMs), widespread CRMs, which occur in rocks that have not been altered by externally derived fluids, need to explained by another mechanism. We are testing clay ...
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