Stratigraphy of the Cretaceous-Tertiary and Paleocene-Eocene Transition Rocks of Big Bend National Park, Texas

Schiebout, Judith A.; Rigsby, Catherine A.; Rapp, Stephen D.; Hartnell, Jill A.; Standhardt, Barbara

doi:10.1086/629135

Cited by 28 publications

(34 citation statements)

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“…6 and 11). Black paleosols are absent in the overlying Eocene Hannold Hill Member (Schiebout et al, 1987). Two fi eld tests using the application of hydrogen peroxide and sodium citrate-bicarbonate-dithionite resulted in a vigorous reaction and a color change, indicating the presence of manganese oxide (Fanning and Fanning, 1989) in the black paleosols.…”

Section: Resultsmentioning

confidence: 99%

“…VPDB-Vienna Peedee belemnite. data (Rapp et al, 1983), the Paleocene-Eocene boundary is ~125 m above the base of the Black Peaks Member in the section and roughly corresponds to the contact between the Black Peaks Member and the Hannold Hill Member (Schiebout et al, 1987) (Fig. 2).…”

Section: Geological Settingmentioning

confidence: 93%

“…Column 3 is the magnetic polarity data for the study area after Rapp et al (1983). Column 4 shows the formation and members in the study area after Schiebout et al (1987). Column 5 (in m) shows the locations of black paleosols.…”

Section: Geological Settingmentioning

confidence: 99%

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Paleogene paleosols and changes in pedogenesis during the initial Eocene thermal maximum: Big Bend National Park, Texas, USA

White

Schiebout

2008

Geological Society of America Bulletin

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This paper tests the hypothesis that continental chemical weathering increased during the initial Eocene thermal maximum (IETM) by comparing paleosols that formed before and during the event in western Texas. The chemical index of alteration (CIA) was used to investigate the weathering of silicate minerals. Paleosols generated before the IETM have CIA values ranging from 62 to 72, and CIA values during the IETM range from 67 to 82. The CIA values for pre-initial Eocene thermal maximum paleosols indicate moderate weathering conditions, and CIA values during the event indicate moderate to extreme weathering conditions. The clay mineralogy of the paleosols is dominated by smectite, and it is only within paleosols that formed during the IETM that there is a change. There is a notable increase in the amount of kaolinite in one paleosol horizon that is associated with the carbon excursion. In addition, there is an increase in the translocation of clays and iron, and an increase in the leaching of calcite and plagioclase in initial Eocene thermal maximum paleosols. The differences between soils that formed before and during the initial Eocene thermal maximum indicate that chemical weathering did increase during this ancient global warming event. The mechanism responsible for increased weathering is interpreted to be an increase in hydrolysis reactions caused by an increase in humidity and an increase of carbonic acid in the soil due to elevated CO 2 levels during the initial Eocene thermal maximum. Documentation of an increase in chemical weathering during the initial Eocene thermal maximum is signifi cant because it may have served as a negative feedback to reduce atmospheric CO 2 .

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Section: Resultsmentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 93%

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Paleogene paleosols and changes in pedogenesis during the initial Eocene thermal maximum: Big Bend National Park, Texas, USA

White

Schiebout

2008

Geological Society of America Bulletin

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“…The paleosols studied in this work are from the Tornillo Basin in Big Bend National Park, Texas (USA), approximately 29°25′N, 103°09′W (Figure ). The Tornillo Basin formed as the southernmost extent of the Laramide orogeny (Lehman, ; Lehman & Busbey, ; Lehman et al, ; Schiebout et al, ; Turner et al, ) and during the early Paleogene was likely at or near the same subtropical latitude as it is today (van Hinsbergen et al, ). There is some evidence for syndepositional deformation in the studied Paleocene and Eocene sediments (Lehman & Busbey, ).…”

Section: Methodsmentioning

confidence: 99%

“…There is some evidence for syndepositional deformation in the studied Paleocene and Eocene sediments (Lehman & Busbey, ). The basin was likely a distal foreland basin with relatively low sediment accumulation rates (Schiebout et al, ). During the Paleogene, the basin was close to the proto‐Gulf of Mexico shoreline and thus preserves a record of a more coastal environment than exists at modern Big Bend (e.g., Galloway et al, ; Sharman et al, ).…”

Section: Methodsmentioning

confidence: 99%

Warm Terrestrial Subtropics During the Paleocene and Eocene: Carbonate Clumped Isotope (Δ₄₇) Evidence From the Tornillo Basin, Texas (USA)

Kelson

Watford

Bataille

et al. 2018

Paleoceanog and Paleoclimatol

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Records of subtropical climate on land from the early Paleogene offer insights into how the Earth system responds to greenhouse climate conditions. Fluvial and floodplain deposits of the Tornillo Basin (Big Bend National Park, Texas, USA) preserve a record of environmental and climatic change of the Paleocene and the early Eocene. We report carbon, oxygen, and clumped isotopic compositions (δ13C, δ18O, and Δ47) of paleosol carbonate nodules from this basin. Mineralogical, geochemical, and thermal modeling evidence suggests that the measured isotopic values preserve primary environmental signals with a summer bias with the exception of data from two nodules reset by local igneous intrusions. The unaltered nodules record Δ47 temperatures of 25 ± 4 and 32 ± 2 °C for the Paleocene and early Eocene nodules, respectively, showing an increase in average summer temperatures of 7 ± 3 °C. Calculations of δ18O of soil water are −2.8 ± 0.7‰ and −0.8 ± 0.4‰ (standard mean ocean water) for the early‐mid‐Paleocene and late Paleocene‐early Eocene, showing an increase of 2.0 ± 0.9‰. The increase in temperature and δ18O values likely relates to a rise in atmospheric pCO2, although we cannot rule out that changes in paleosol texture and regional precipitation patterns also influence the record. Comparison with Δ47 estimates of summer temperature from the Green River and Bighorn Basins (WY) highlights that terrestrial surface temperatures are heterogeneous, and latitudinal temperature gradients on land remain undetermined. Previously published paleoclimate models predict summer temperatures that are 2 to 6 °C higher than our estimate; discrepancies between climate models and proxy data persist at lower latitudes.

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Unveiling the elusive: X‐rays bring scolecophidian snakes out of the dark

Bell

Daza

Stanley³

et al. 2021

The Anatomical Record

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Scolecophidian snakes have long posed challenges for scholars interested in elucidating their anatomy. The importance, and relative paucity, of highquality anatomical data pertaining to scolecophidians was brought into sharp focus in the late 20 th century as part of a controversy over the phylogeny and ecological origin of snakes. The basal position of scolecophidians in the phylogeny of snakes makes their anatomy, behavior, ecology, and evolution especially important for such considerations. The depauperate fossil record for the group meant that advances in understanding their evolutionary history were necessarily tied to biogeographic distributions and anatomical interpretations of extant taxa. Osteological data, especially data pertaining to the skull and mandible, assumed a dominant role in shaping historical and modern perspectives of the evolution of scolecophidians. Traditional approaches to the exploration of the anatomy of these snakes relied heavily upon serial-sectioned specimens and cleared-and-stained specimens. The application of X-ray computed tomography (CT) to the study of scolecophidians revolutionized our understanding of the osteology of the group, and now, via diffusible iodinebased contrast-enhanced computed tomography (diceCT), is yielding data sets on internal soft anatomical features as well. CT data sets replicate many aspects of traditional anatomical preparations, are readily shared with a global community of scholars, and now are available for unique holotype and other rare specimens. The increasing prevalence and relevance of CT data sets is a strong incentive for the establishment and maintenance of permanent repositories for digital data.

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Stratigraphy of the Cretaceous-Tertiary and Paleocene-Eocene Transition Rocks of Big Bend National Park, Texas

Cited by 28 publications

References 10 publications

Paleogene paleosols and changes in pedogenesis during the initial Eocene thermal maximum: Big Bend National Park, Texas, USA

Paleogene paleosols and changes in pedogenesis during the initial Eocene thermal maximum: Big Bend National Park, Texas, USA

Warm Terrestrial Subtropics During the Paleocene and Eocene: Carbonate Clumped Isotope (Δ₄₇) Evidence From the Tornillo Basin, Texas (USA)

Unveiling the elusive: X‐rays bring scolecophidian snakes out of the dark

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Stratigraphy of the Cretaceous-Tertiary and Paleocene-Eocene Transition Rocks of Big Bend National Park, Texas

Cited by 28 publications

References 10 publications

Paleogene paleosols and changes in pedogenesis during the initial Eocene thermal maximum: Big Bend National Park, Texas, USA

Paleogene paleosols and changes in pedogenesis during the initial Eocene thermal maximum: Big Bend National Park, Texas, USA

Warm Terrestrial Subtropics During the Paleocene and Eocene: Carbonate Clumped Isotope (Δ47) Evidence From the Tornillo Basin, Texas (USA)

Unveiling the elusive: X‐rays bring scolecophidian snakes out of the dark

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Warm Terrestrial Subtropics During the Paleocene and Eocene: Carbonate Clumped Isotope (Δ₄₇) Evidence From the Tornillo Basin, Texas (USA)