The Experts below are selected from a list of 81 Experts worldwide ranked by ideXlab platform
Kristin D Bergmann - One of the best experts on this subject based on the ideXlab platform.
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spatial variation in late ordovician glacioeustatic sea level change
Earth and Planetary Science Letters, 2018Co-Authors: Jessica R Creveling, Seth Finnegan, Jerry X. Mitrovica, Kristin D BergmannAbstract:Abstract Mass extinction of Late Ordovician marine fauna closely coincided with southern hemisphere glaciation. The sequence stratigraphic architecture of shallow marine deposits informs estimates of glacioeustatic sea-level change at sites both proximal and distal to the reconstructed Ordovician ice sheet(s) and contemporaneous changes in ice volume. A recent correlation framework for the stratigraphic architectures of one near and one far field Late Ordovician margin concluded that the Late Ordovician glaciation encompassed multiple long-term cycles of ice volume growth and retreat with superimposed higher frequency cycles. Here we posit that—similar to Cenozoic glacial cycles—glacial isostatic adjustment can preclude synchronous and similar magnitude (or directional) changes in Late Ordovician sea level between ice proximal and ice distal locations and, hence, distort a globally correlative sequence stratigraphy. We explored whether long-duration (i.e., million year) Late Ordovician glacial cycles should produce a globally coherent, eustatic record of sea-level change between ice proximal and ice distal margins using a gravitationally self-consistent theory that accounts for the deformational, gravitational and rotational perturbations to sea level on a viscoelastic Earth model. We adopted a Late Ordovician paleogeography and a synthetic continental ice-sheet distribution and volume informed by the areal extent of glaciogenic deposits and geochemical records, respectively. We demonstrate that modeled million year Late Ordovician glacial cycles produce sea-level histories on near and far field margins that differ from eustasy, and from one another, due primarily to elastic flexure and associated gravitational effects. While predicted far-field sea-level histories faithfully preserve the temporal structure of modeled glacioeustasy, their amplitude may differ from eustasy by as much as 30–40%. The impact of glacial isostatic adjustment is largest at the margins of glaciated continents, and these effects can be of the same order of magnitude as the eustatic, and even induce a local sea-level rise during an episode of ice growth and eustatic sea-level fall, and vice versa. In this regard, stratal surfaces of maximum regression and flooding expressed at near-field margins need not reflect global (‘eustatic’) trends in ice sheet growth and decay, respectively, and thus may not provide chronostratigraphic horizons for correlation with far-field sequence stratigraphic architectures.
Jessica R Creveling - One of the best experts on this subject based on the ideXlab platform.
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spatial variation in late ordovician glacioeustatic sea level change
Earth and Planetary Science Letters, 2018Co-Authors: Jessica R Creveling, Seth Finnegan, Jerry X. Mitrovica, Kristin D BergmannAbstract:Abstract Mass extinction of Late Ordovician marine fauna closely coincided with southern hemisphere glaciation. The sequence stratigraphic architecture of shallow marine deposits informs estimates of glacioeustatic sea-level change at sites both proximal and distal to the reconstructed Ordovician ice sheet(s) and contemporaneous changes in ice volume. A recent correlation framework for the stratigraphic architectures of one near and one far field Late Ordovician margin concluded that the Late Ordovician glaciation encompassed multiple long-term cycles of ice volume growth and retreat with superimposed higher frequency cycles. Here we posit that—similar to Cenozoic glacial cycles—glacial isostatic adjustment can preclude synchronous and similar magnitude (or directional) changes in Late Ordovician sea level between ice proximal and ice distal locations and, hence, distort a globally correlative sequence stratigraphy. We explored whether long-duration (i.e., million year) Late Ordovician glacial cycles should produce a globally coherent, eustatic record of sea-level change between ice proximal and ice distal margins using a gravitationally self-consistent theory that accounts for the deformational, gravitational and rotational perturbations to sea level on a viscoelastic Earth model. We adopted a Late Ordovician paleogeography and a synthetic continental ice-sheet distribution and volume informed by the areal extent of glaciogenic deposits and geochemical records, respectively. We demonstrate that modeled million year Late Ordovician glacial cycles produce sea-level histories on near and far field margins that differ from eustasy, and from one another, due primarily to elastic flexure and associated gravitational effects. While predicted far-field sea-level histories faithfully preserve the temporal structure of modeled glacioeustasy, their amplitude may differ from eustasy by as much as 30–40%. The impact of glacial isostatic adjustment is largest at the margins of glaciated continents, and these effects can be of the same order of magnitude as the eustatic, and even induce a local sea-level rise during an episode of ice growth and eustatic sea-level fall, and vice versa. In this regard, stratal surfaces of maximum regression and flooding expressed at near-field margins need not reflect global (‘eustatic’) trends in ice sheet growth and decay, respectively, and thus may not provide chronostratigraphic horizons for correlation with far-field sequence stratigraphic architectures.
Jerry X. Mitrovica - One of the best experts on this subject based on the ideXlab platform.
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spatial variation in late ordovician glacioeustatic sea level change
Earth and Planetary Science Letters, 2018Co-Authors: Jessica R Creveling, Seth Finnegan, Jerry X. Mitrovica, Kristin D BergmannAbstract:Abstract Mass extinction of Late Ordovician marine fauna closely coincided with southern hemisphere glaciation. The sequence stratigraphic architecture of shallow marine deposits informs estimates of glacioeustatic sea-level change at sites both proximal and distal to the reconstructed Ordovician ice sheet(s) and contemporaneous changes in ice volume. A recent correlation framework for the stratigraphic architectures of one near and one far field Late Ordovician margin concluded that the Late Ordovician glaciation encompassed multiple long-term cycles of ice volume growth and retreat with superimposed higher frequency cycles. Here we posit that—similar to Cenozoic glacial cycles—glacial isostatic adjustment can preclude synchronous and similar magnitude (or directional) changes in Late Ordovician sea level between ice proximal and ice distal locations and, hence, distort a globally correlative sequence stratigraphy. We explored whether long-duration (i.e., million year) Late Ordovician glacial cycles should produce a globally coherent, eustatic record of sea-level change between ice proximal and ice distal margins using a gravitationally self-consistent theory that accounts for the deformational, gravitational and rotational perturbations to sea level on a viscoelastic Earth model. We adopted a Late Ordovician paleogeography and a synthetic continental ice-sheet distribution and volume informed by the areal extent of glaciogenic deposits and geochemical records, respectively. We demonstrate that modeled million year Late Ordovician glacial cycles produce sea-level histories on near and far field margins that differ from eustasy, and from one another, due primarily to elastic flexure and associated gravitational effects. While predicted far-field sea-level histories faithfully preserve the temporal structure of modeled glacioeustasy, their amplitude may differ from eustasy by as much as 30–40%. The impact of glacial isostatic adjustment is largest at the margins of glaciated continents, and these effects can be of the same order of magnitude as the eustatic, and even induce a local sea-level rise during an episode of ice growth and eustatic sea-level fall, and vice versa. In this regard, stratal surfaces of maximum regression and flooding expressed at near-field margins need not reflect global (‘eustatic’) trends in ice sheet growth and decay, respectively, and thus may not provide chronostratigraphic horizons for correlation with far-field sequence stratigraphic architectures.
Seth Finnegan - One of the best experts on this subject based on the ideXlab platform.
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spatial variation in late ordovician glacioeustatic sea level change
Earth and Planetary Science Letters, 2018Co-Authors: Jessica R Creveling, Seth Finnegan, Jerry X. Mitrovica, Kristin D BergmannAbstract:Abstract Mass extinction of Late Ordovician marine fauna closely coincided with southern hemisphere glaciation. The sequence stratigraphic architecture of shallow marine deposits informs estimates of glacioeustatic sea-level change at sites both proximal and distal to the reconstructed Ordovician ice sheet(s) and contemporaneous changes in ice volume. A recent correlation framework for the stratigraphic architectures of one near and one far field Late Ordovician margin concluded that the Late Ordovician glaciation encompassed multiple long-term cycles of ice volume growth and retreat with superimposed higher frequency cycles. Here we posit that—similar to Cenozoic glacial cycles—glacial isostatic adjustment can preclude synchronous and similar magnitude (or directional) changes in Late Ordovician sea level between ice proximal and ice distal locations and, hence, distort a globally correlative sequence stratigraphy. We explored whether long-duration (i.e., million year) Late Ordovician glacial cycles should produce a globally coherent, eustatic record of sea-level change between ice proximal and ice distal margins using a gravitationally self-consistent theory that accounts for the deformational, gravitational and rotational perturbations to sea level on a viscoelastic Earth model. We adopted a Late Ordovician paleogeography and a synthetic continental ice-sheet distribution and volume informed by the areal extent of glaciogenic deposits and geochemical records, respectively. We demonstrate that modeled million year Late Ordovician glacial cycles produce sea-level histories on near and far field margins that differ from eustasy, and from one another, due primarily to elastic flexure and associated gravitational effects. While predicted far-field sea-level histories faithfully preserve the temporal structure of modeled glacioeustasy, their amplitude may differ from eustasy by as much as 30–40%. The impact of glacial isostatic adjustment is largest at the margins of glaciated continents, and these effects can be of the same order of magnitude as the eustatic, and even induce a local sea-level rise during an episode of ice growth and eustatic sea-level fall, and vice versa. In this regard, stratal surfaces of maximum regression and flooding expressed at near-field margins need not reflect global (‘eustatic’) trends in ice sheet growth and decay, respectively, and thus may not provide chronostratigraphic horizons for correlation with far-field sequence stratigraphic architectures.
H.s.m. Jansen - One of the best experts on this subject based on the ideXlab platform.
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Reply to ‘Comment on The geometry and stratigraphic position of the Maassluis Formation (western Netherlands and south-eastern North Sea)’
Geologie En Mijnbouw, 2005Co-Authors: H.s.m. JansenAbstract:In their comment, Wesselingh et al. say that pronounced Glacioeustacy renders the detailed discussions about age intervals obsolete and that they fail to see the application of the Haq curves for age estimates in the Maassluis Formation can make much sense. We would argue the following: - Eustacy and sediment supply are the driving forces behind sequence formation and configuration. As our model shows, the overall picture of the Pliocene/Pleistocene along our transect is one of an outbuilding system, going from open marine to terrestrial deposits, which is a classic sequence stratigraphic configuration.- The lower part of the Maassluis Formation in the Noordwijk borehole lies below an unconformity and consists of open marine sediments as opposed to the coastal sediments of the upper part. Since it is the normal transition over a sequence boundary, there is reason to speculate about which sequences we are looking at here and what their age is. There is a large sedimentary wedge to the west of Noordwijk that is missing in the Noordwijk borehole.- The glacial-interglacial cycles Meijer et al. (in press) refer to are likely to be better expressed in the coastal part of the formation, i.e. from ca. 2.55 Ma. This is also the part of the formation where micro-vertebrates will be found, not the (older) marine part. These cycles do not alter the overall sequence stratigraphic model, they add a climatic overprint of smaller sedimentary cycles.