The Late Mississippian represents a time when Earth was thought to be an icehouse and was experie... more The Late Mississippian represents a time when Earth was thought to be an icehouse and was experiencing eustatic sea level changes similar to today. While there’s been a wealth of research done in the western equatorial Pangea for the Late Carboniferous and Permian, this study of the Pennington Formation, Tennessee, offers an opportunity to study less focused upon terrestrial early Carboniferous paleoenvironments from central equatorial Pangea, including the effects of diagenesis on paleoenvironmental proxies employed for paleosol research. New fieldwork of an outcrop outside Sparta, TN shows interbedded limestone and mudstone layers including four paleosol profiles that have been described and analyzed for their principle clay mineralogy. The paleosols preserve typical vertic features including slickensides, mukkara and wedge-shaped peds as well as low chroma color and are thus gleyed Vertisols. The gleyed nature of these paleosols is either the result of forming under waterlogged conditions seen today in soils forming proximal to shorelines or the result of diagenesis associated with sea level rising. The presence of Vertisols intercalated between limestones suggests a persistent influence of glacioeustacy in conjunction with highly seasonal climates during base-level lowstands and soil development which gave rise to pedoturbation and the characteristic suite of vertic morphologies seen in outcrop. Clay mineralogy dominated by illite and vermiculite suggests burial diagenesis. This contrasts sites from the upper Pennsylvanian which contain evidence for eustatic sea level change but are suggestive of more ever-wet conditions and recorded by the common occurrence of thick coal layers atop mineral-dominated paleosol profiles.
Raw data for Ecological dynamic equilibrium in an early Miocene (21.7 Ma) forest, Ethiopia by E.D... more Raw data for Ecological dynamic equilibrium in an early Miocene (21.7 Ma) forest, Ethiopia by E.D. Currano, B.F. Jacobs, R.T. Bush, A. Novello, M. Feseha, F. Grímsson, F.A. McInerney, L. Michel, A.D. Pan, S. Phelps, P. Polissar, C.A.E. Strömberg, N.J. Tabor. This includes phytolith counts, leaf macrofossil counts, and lipid abundances and carbon isotope values.
Recent variations in the concentration of atmospheric carbon dioxide ([CO2]atm) have been shown t... more Recent variations in the concentration of atmospheric carbon dioxide ([CO2]atm) have been shown to affect carbon fixation during photosynthesis and are correlated with anatomical and physiological changes observed in leaves of woody dicots. These include changes in stomatal frequency and size and in δ13C values. These attributes can be measured on organically preserved leaf fossils, and therefore can be used as proxies for Earth’s atmospheric CO2 history. This study tests the link between [CO2]atm and global temperature for the late Oligocene and early Miocene using fossil leaves collected from Ethiopia, by estimating [CO2]atm using a leaf gas exchange model. The results of this study show a statistically significant [CO2]atm rise from ~390 ppm in the late Oligocene to ~870 ppm in the early Miocene. These values demonstrate a positive correlation between [CO2]atm and global average temperature, contrary to some previous studies for this time interval. The results of this study have important implications for understanding future climate change driven by rising [CO2]atm
Raw data for Ecological dynamic equilibrium in an early Miocene (21.7 Ma) forest, Ethiopia by E.D... more Raw data for Ecological dynamic equilibrium in an early Miocene (21.7 Ma) forest, Ethiopia by E.D. Currano, B.F. Jacobs, R.T. Bush, A. Novello, M. Feseha, F. Grímsson, F.A. McInerney, L. Michel, A.D. Pan, S. Phelps, P. Polissar, C.A.E. Strömberg, N.J. Tabor. This includes phytolith counts, leaf macrofossil counts, and lipid abundances and carbon isotope values.
The Late Mississippian represents a time when Earth was thought to be an icehouse and was experie... more The Late Mississippian represents a time when Earth was thought to be an icehouse and was experiencing eustatic sea level changes similar to today. While there’s been a wealth of research done in the western equatorial Pangea for the Late Carboniferous and Permian, this study of the Pennington Formation, Tennessee, offers an opportunity to study less focused upon terrestrial early Carboniferous paleoenvironments from central equatorial Pangea, including the effects of diagenesis on paleoenvironmental proxies employed for paleosol research. New fieldwork of an outcrop outside Sparta, TN shows interbedded limestone and mudstone layers including four paleosol profiles that have been described and analyzed for their principle clay mineralogy. The paleosols preserve typical vertic features including slickensides, mukkara and wedge-shaped peds as well as low chroma color and are thus gleyed Vertisols. The gleyed nature of these paleosols is either the result of forming under waterlogged c...
The Late Mississippian represents a time when Earth was thought to be an icehouse and was experie... more The Late Mississippian represents a time when Earth was thought to be an icehouse and was experiencing eustatic sea level changes similar to today. While there’s been a wealth of research done in the western equatorial Pangea for the Late Carboniferous and Permian, this study of the Pennington Formation, Tennessee, offers an opportunity to study less focused upon terrestrial early Carboniferous paleoenvironments from central equatorial Pangea, including the effects of diagenesis on paleoenvironmental proxies employed for paleosol research. New fieldwork of an outcrop outside Sparta, TN shows interbedded limestone and mudstone layers including four paleosol profiles that have been described and analyzed for their principle clay mineralogy. The paleosols preserve typical vertic features including slickensides, mukkara and wedge-shaped peds as well as low chroma color and are thus gleyed Vertisols. The gleyed nature of these paleosols is either the result of forming under waterlogged conditions seen today in soils forming proximal to shorelines or the result of diagenesis associated with sea level rising. The presence of Vertisols intercalated between limestones suggests a persistent influence of glacioeustacy in conjunction with highly seasonal climates during base-level lowstands and soil development which gave rise to pedoturbation and the characteristic suite of vertic morphologies seen in outcrop. Clay mineralogy dominated by illite and vermiculite suggests burial diagenesis. This contrasts sites from the upper Pennsylvanian which contain evidence for eustatic sea level change but are suggestive of more ever-wet conditions and recorded by the common occurrence of thick coal layers atop mineral-dominated paleosol profiles.
Raw data for Ecological dynamic equilibrium in an early Miocene (21.7 Ma) forest, Ethiopia by E.D... more Raw data for Ecological dynamic equilibrium in an early Miocene (21.7 Ma) forest, Ethiopia by E.D. Currano, B.F. Jacobs, R.T. Bush, A. Novello, M. Feseha, F. Grímsson, F.A. McInerney, L. Michel, A.D. Pan, S. Phelps, P. Polissar, C.A.E. Strömberg, N.J. Tabor. This includes phytolith counts, leaf macrofossil counts, and lipid abundances and carbon isotope values.
Recent variations in the concentration of atmospheric carbon dioxide ([CO2]atm) have been shown t... more Recent variations in the concentration of atmospheric carbon dioxide ([CO2]atm) have been shown to affect carbon fixation during photosynthesis and are correlated with anatomical and physiological changes observed in leaves of woody dicots. These include changes in stomatal frequency and size and in δ13C values. These attributes can be measured on organically preserved leaf fossils, and therefore can be used as proxies for Earth’s atmospheric CO2 history. This study tests the link between [CO2]atm and global temperature for the late Oligocene and early Miocene using fossil leaves collected from Ethiopia, by estimating [CO2]atm using a leaf gas exchange model. The results of this study show a statistically significant [CO2]atm rise from ~390 ppm in the late Oligocene to ~870 ppm in the early Miocene. These values demonstrate a positive correlation between [CO2]atm and global average temperature, contrary to some previous studies for this time interval. The results of this study have important implications for understanding future climate change driven by rising [CO2]atm
Raw data for Ecological dynamic equilibrium in an early Miocene (21.7 Ma) forest, Ethiopia by E.D... more Raw data for Ecological dynamic equilibrium in an early Miocene (21.7 Ma) forest, Ethiopia by E.D. Currano, B.F. Jacobs, R.T. Bush, A. Novello, M. Feseha, F. Grímsson, F.A. McInerney, L. Michel, A.D. Pan, S. Phelps, P. Polissar, C.A.E. Strömberg, N.J. Tabor. This includes phytolith counts, leaf macrofossil counts, and lipid abundances and carbon isotope values.
The Late Mississippian represents a time when Earth was thought to be an icehouse and was experie... more The Late Mississippian represents a time when Earth was thought to be an icehouse and was experiencing eustatic sea level changes similar to today. While there’s been a wealth of research done in the western equatorial Pangea for the Late Carboniferous and Permian, this study of the Pennington Formation, Tennessee, offers an opportunity to study less focused upon terrestrial early Carboniferous paleoenvironments from central equatorial Pangea, including the effects of diagenesis on paleoenvironmental proxies employed for paleosol research. New fieldwork of an outcrop outside Sparta, TN shows interbedded limestone and mudstone layers including four paleosol profiles that have been described and analyzed for their principle clay mineralogy. The paleosols preserve typical vertic features including slickensides, mukkara and wedge-shaped peds as well as low chroma color and are thus gleyed Vertisols. The gleyed nature of these paleosols is either the result of forming under waterlogged c...
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