Mid-Pliocene shorelines of the US Atlantic Coastal Plain — An improved elevation database with comparison to Earth model predictions

Hearty, Paul J.; Austermann, Jacqueline; Mitrovica, J. X.; Gale, J; Moucha, R.; Forte, A. M.; Raymo, Maureen E

doi:10.1016/j.earscirev.2015.02.007

Cited by 50 publications

(63 citation statements)

References 74 publications

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“…This behavior occurs in addition to dynamic topography effects and can overprint it, although the growth and decay of ice sheets and their deformational timescales are significantly shorter. A mid-Pliocene (3.1 ± 0.2 Ma) shoreline, known as the Orangeburg Scarp, can be traced from Virginia down to south Georgia at elevations of 40-80 m above present-day sea-level [Rovere et al, 2015]. Eocene and Miocene paleoshorelines along the New Jersey coastal plain have been compared to global sea-level curves and record 50-200 m of anomalous post-Eocene subsidence [Spasojević et al, 2008].…”

Section: D1 Eastern North Americamentioning

confidence: 99%

Oceanic residual depth measurements, the plate cooling model, and global dynamic topography

Hoggard¹,

et al. 2017

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Convective circulation of the mantle causes deflections of the Earth's surface that vary as a function of space and time. Accurate measurements of this dynamic topography are complicated by the need to isolate and remove other sources of elevation, arising from flexure and lithospheric isostasy. The complex architecture of continental lithosphere means that measurement of present‐day dynamic topography is more straightforward in the oceanic realm. Here we present an updated methodology for calculating oceanic residual bathymetry, which is a proxy for dynamic topography. Corrections are applied that account for the effects of sedimentary loading and compaction, for anomalous crustal thickness variations, for subsidence of oceanic lithosphere as a function of age and for non‐hydrostatic geoid height variations. Errors are formally propagated to estimate measurement uncertainties. We apply this methodology to a global database of 1936 seismic surveys located on oceanic crust and generate 2297 spot measurements of residual topography, including 1161 with crustal corrections. The resultant anomalies have amplitudes of ±1 km and wavelengths of ∼1000 km. Spectral analysis of our database using cross‐validation demonstrates that spherical harmonics up to and including degree 30 (i.e., wavelengths down to 1300 km) are required to accurately represent these observations. Truncation of the expansion at a lower maximum degree erroneously increases the amplitude of inferred long‐wavelength dynamic topography. There is a strong correlation between our observations and free‐air gravity anomalies, magmatism, ridge seismicity, vertical motions of adjacent rifted margins, and global tomographic models. We infer that shorter wavelength components of the observed pattern of dynamic topography may be attributable to the presence of thermal anomalies within the shallow asthenospheric mantle.

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Section: D1 Eastern North Americamentioning

confidence: 99%

Oceanic residual depth measurements, the plate cooling model, and global dynamic topography

Hoggard¹,

et al. 2017

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“…We compiled 1,410 previously published delineations of relict shoreline features (RSF) across the southeastern U.S. Coastal Plain (Figures and S1–S6; Daniels & Kane, ; Lane, ; Rovere et al, [digital format]; Winker & Howard, , ) and digitized them in ArcMAP (version 10.5.1) using the georeferencing menu and adding control points to hard copy maps and the reference layer. For each SSURGO MU and each B′h observation we calculated the distance to the nearest RSF delineation with the Near tool in ArcMAP.…”

Section: Methodsmentioning

confidence: 97%

A Billion Tons of Unaccounted for Carbon in the Southeastern United States

Gonzalez

Bacon

Harris

2018

Geophysical Research Letters

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Because Earth's soil contains more carbon than the atmosphere and all terrestrial vegetation combined, forecasting and managing the global carbon cycle in the face of natural and anthropogenic change requires accurate representations of this carbon. Here from regional geomorphic and soil databases, we characterize the mass, distribution, and cycling of previously unaccounted for soil carbon across the southeastern U.S. Coastal Plain, referred to as “deep‐podzolized carbon.” We show that geomorphologic‐hydrologic interactions stabilize approximately 1.1 × 10−9 t of deep‐podzolized carbon (equivalent to roughly 18% of the soil organic carbon stored across the entire region from 0–30 cm), and that this potentially ancient carbon is predictably distributed coincident with Pleistocene marine transgressions. We not only redefine soil carbon storage in the region but we also introduce the Earth Sciences to a massive organic carbon pool that interacts with landscape evolution and hydrology, has essentially never been studied, and is ripe for interdisciplinary research.

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“…Here we consider a model of global dynamic topography, discussed below, that provides a good reconciliation with regional geologic observations across the globe (e.g. Austermann & Mitrovica, ; Forte et al, ; Moucha & Forte, ; Moucha & Ruetenik, ; Rowley et al, ; Rovere et al, ; Walker et al, ). Dynamic topography models in ocean basins are not very well constrained, due to the sparse seismic resolution of the upper mantle in the underlying tomography models.…”

Section: Methodsmentioning

confidence: 99%

Effects of Dynamic Topography on the Cenozoic Carbonate Compensation Depth

Campbell

Moucha

Derry

et al. 2018

Geochem Geophys Geosyst

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Reconstructions of the carbonate compensation depth (CCD) in the past have been used to inform hypotheses about the nature of weathering, tectonics, climate change, and the major ion content of the world's oceans over the Cenozoic. These reconstructions are sensitive to uncertainties in the input data, in particular, the paleodepth estimates of sediment cores. Here we propose that a significant, previously unconsidered contributor to uncertainties in paleodepth estimates is from dynamic topography produced by radial stresses exerted on the Earth's surface by the convecting mantle; these stresses can warp the ocean floor by hundreds of meters over broad regions and also vary significantly over millions of years. We present new reconstructions of the equatorial Pacific and Indian Ocean CCDs over the last 30 and 23 Myr, respectively, which demonstrate an overall deepening trend since the Miocene, and illustrate the possible effect of long‐term changes in dynamic topography on these reconstructions.

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Mid-Pliocene shorelines of the US Atlantic Coastal Plain — An improved elevation database with comparison to Earth model predictions

Cited by 50 publications

References 74 publications

Oceanic residual depth measurements, the plate cooling model, and global dynamic topography

Oceanic residual depth measurements, the plate cooling model, and global dynamic topography

A Billion Tons of Unaccounted for Carbon in the Southeastern United States

Effects of Dynamic Topography on the Cenozoic Carbonate Compensation Depth

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