Digital elevations and extents of regional hydrogeologic units in the Northern Atlantic Coastal Plain aquifer system from Long Island, New York, to North Carolina

Pope, Jason P.; Andreasen, David C.; McFarland, E. R.; Watt, Martha K.

doi:10.3133/ds996

“…Our model in the southern ENAM reveals that the Moho deepens from ∼15 km to ∼40–45 km over a horizontal distance of ∼70 km across the oceanic‐continental margin (Figures 3 and ). In comparison, the Moho depth increases gradually from ∼15 km landward to ∼45–50 km over a wide zone of ∼200 km beneath the continental shelf of southern New England (e.g., Lang et al., 2020; Pope et al., 2016). We proposed that the difference in the lateral width of the transitional crust along the ENAM indicates that the crust experienced more localized extension in the south than in the north during the Mesozoic rifting.…”

Section: Discussionmentioning

confidence: 99%

Modification of Crust and Mantle Lithosphere Beneath the Southern Part of the Eastern North American Passive Margin

Li

¹

,

Gao

²

2021

Geophysical Research Letters

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The eastern North American margin (ENAM; Figure 1a) represents an archetypical passive margin, which experienced the assembly and breakup of the supercontinent Pangea over the last 500 Ma (Thomas, 2006). During the assembly of Pangea between ∼495 Ma and ∼270 Ma, a sequence of tectonic terranes progressively accreted onto the North American craton (namely Laurentia) (Hatcher, 2010;Thomas, 2006). Extensive rifting along the ENAM started at ∼230 Ma (Withjack et al., 2012), and was accompanied by short-lived igneous activities. Enormous postrifting magmatism occurred over a period of less than 1 million years at ∼200 Ma and formed one of the Earth's largest igneous provinces, the Central Atlantic Magmatic Province (Marzoli et al., 1999(Marzoli et al., , 2018. Rifting led to the breakup of Pangea at ∼185 Ma, and the modern passive margin was ultimately established (Withjack et al., 2012).The southern segment of the ENAM is characterized by a variety of tectonic features associated with both syn-and postrifting tectonic events. For example, a positive magnetic anomaly (namely the East Coast Magnetic Anomaly) aligns approximately in the SW-NE direction (Figures 1 and S1a). The East Coast Magnetic Anomaly likely represents volcanism that was associated with the initial rifting at ∼230 Ma, and thus marks the boundary between the oceanic and continental lithosphere (Austin et al., 1990;Klitgord

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“…Red diamonds are locations of LASE (1986) expanded spread profile data. Onshore depth to base of coastal plain aquifer is from Pope et al (2016). Bathymetry data are from Andrews et al (2013).…”

Section: Methodsmentioning

confidence: 99%

The Role of Premagmatic Rifting in Shaping a Volcanic Continental Margin: An Example From the Eastern North American Margin

Lang

¹

,

Brink

²

,

Hutchinson

³

et al. 2020

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Both magmatic and tectonic processes contribute to the formation of volcanic continental margins. Such margins are thought to undergo extension across a narrow zone of lithospheric thinning (~100 km). New observations based on existing and reprocessed data from the Eastern North American Margin contradict this hypothesis. With~64,000 km of 2-D seismic data tied to 40 wells combined with published refraction, deep reflection, receiver function, and onshore drilling efforts, we quantified along-strike variations in the distribution of rift structures, magmatism, crustal thickness, and early post-rift sedimentation under the shelf of Baltimore Canyon Trough (BCT), Long Island Platform, and Georges Bank Basin (GBB). Results indicate that BCT is narrow (80-120 km) with a sharp basement hinge and few rift basins. The seaward dipping reflectors (SDR) there extend~50 km seaward of the hinge line. In contrast, the GBB is wide (~200 km), has many syn-rift structures, and the SDR there extend~200 km seaward of the hinge line. Early post-rift depocenters at the GBB coincide with thinner crust suggesting "uniform" thinning of the entire lithosphere. Models for the formation of volcanic margins do not explain the wide structure of the GBB. We argue that crustal thinning of the BCT was closely associated with late syn-rift magmatism, whereas the broad thinning of the GBB segment predated magmatism. Correlation of these variations to crustal terranes of different compositions suggests that the inherited rheology determined the premagmatic response of the lithosphere to extension.

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“…This makes their domain conversion function more straightforward compared with most of the TWT data which are found in areas with thicker 1986) expanded spread profile data. Onshore depth to base of coastal plain aquifer is from Pope et al (2016). Bathymetry data are from Andrews et al (2013).…”

Section: Methodsmentioning

confidence: 99%

“…Red diamonds are locations of LASE (1986) expanded spread profile data. Onshore depth to base of coastal plain aquifer is fromPope et al (2016). Bathymetry data are fromAndrews et al (2013).…”

mentioning

confidence: 99%

“…(a) Dip-oriented section across the southern Baltimore canyon trough coastal plain to continental rise based on MA-032 time-migrated multichannel reflection profile. Magnetic anomaly profile is shown across the top of the section.Position of the base post-rift west of the coastline is afterPope et al (2016). Position of the Moho, top basement under the SDR, seaward limit of continental crust, and the presence of high-velocity lower crust are interpolated based on adjacent (~13 km) refraction data(Lizarralde & Holbrook, 1997;Sheridan et al, 1993;Talwani et al, 1995).…”

mentioning

confidence: 99%

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The role of pre-magmatic rifting in shaping a volcanic continental margin: An example from the Eastern North American Margin

Lang

¹

,

Brink

²

,

Hutchinson

³

et al. 2020

Preprint

0

View full text Add to dashboard Cite

Both magmatic and tectonic processes contribute to the formation of volcanic continental margins. Such margins are thought to undergo extension across a narrow zone of lithospheric thinning (~100 km). New observations based on existing and reprocessed data from the Eastern North American Margin contradict this hypothesis. With~64,000 km of 2-D seismic data tied to 40 wells combined with published refraction, deep reflection, receiver function, and onshore drilling efforts, we quantified along-strike variations in the distribution of rift structures, magmatism, crustal thickness, and early post-rift sedimentation under the shelf of Baltimore Canyon Trough (BCT), Long Island Platform, and Georges Bank Basin (GBB). Results indicate that BCT is narrow (80-120 km) with a sharp basement hinge and few rift basins. The seaward dipping reflectors (SDR) there extend~50 km seaward of the hinge line. In contrast, the GBB is wide (~200 km), has many syn-rift structures, and the SDR there extend~200 km seaward of the hinge line. Early post-rift depocenters at the GBB coincide with thinner crust suggesting "uniform" thinning of the entire lithosphere. Models for the formation of volcanic margins do not explain the wide structure of the GBB. We argue that crustal thinning of the BCT was closely associated with late syn-rift magmatism, whereas the broad thinning of the GBB segment predated magmatism. Correlation of these variations to crustal terranes of different compositions suggests that the inherited rheology determined the premagmatic response of the lithosphere to extension.

show abstract

Digital elevations and extents of regional hydrogeologic units in the Northern Atlantic Coastal Plain aquifer system from Long Island, New York, to North Carolina

Cited by 8 publications

References 3 publications

Modification of Crust and Mantle Lithosphere Beneath the Southern Part of the Eastern North American Passive Margin

Modification of Crust and Mantle Lithosphere Beneath the Southern Part of the Eastern North American Passive Margin

The Role of Premagmatic Rifting in Shaping a Volcanic Continental Margin: An Example From the Eastern North American Margin

The role of pre-magmatic rifting in shaping a volcanic continental margin: An example from the Eastern North American Margin

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