Modification of Lithospheric Structure Beneath Connecticut via Subduction, Terrane Accretion, and Rifting: Insights From the Seisconn Experiment

Long, Maureen D.; Aragon, John C.; Yang, Xiaotao; Gao, Haiying; Goldhagen, Gillian; Ford, H. A.; Kuiper, Yvette D.

doi:10.1130/abs/2019ne-327980

Cited by 3 publications

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“…At depths greater than about 30 km, the major velocity features in our velocity model are primarily inherited from the reference model ( Figure S6). In order to investigate the crustal structure beneath the Hartford basin and its surroundings, we present the shear-wave velocities at depths of 6, 11, 18, and 25 km ( Figure 2), a west-east velocity profile along the SEISConn array (Figure 3a), the crustal thickness defined by teleseismic P wave 10.1029/2020GL089316 receiver function analysis of the SEISConn stations by Long et al (2018) (Figure 3b), and the extracted 1-D velocity profiles at three points along the SEISConn array ( Figure 3c). Receiver function analysis (Long et al, 2018; Figure 3b) revealed a relatively shallow (30 ± 5 km) Moho beneath the central Hartford basin in comparison with its western and eastern uplands (40-45 km, with particularly thick crust at the western end of the array).…”

Section: Resultsmentioning

confidence: 99%

“…(a) Shear‐wave velocity profile approximately along the SEISConn array within a depth range of 5–55 km. The dot‐connected solid line is the estimated crust‐mantle boundary (Moho) from teleseismic receiver function analysis by Long et al (2018), and each red dot represents one seismic station and corresponds to the migrated receiver function traces in (b). The dashed line shows the velocity contour at 4.0 km/s to highlight the high‐velocity crustal root.…”

Section: Resultsmentioning

confidence: 99%

“…In this scenario, extension and crustal thinning in the late Triassic due to the ENAM rifting (Withjack et al, 2012) may have resulted in midcrustal radial anisotropy and provided the accommodation for the voluminous intrusion of the CAMP magmas into the lower crust. The high‐velocity crustal root beneath the central Hartford basin, where crustal thinning is observed (Li et al, 2018; Long et al, 2018), reflects the remnant of mafic magmatic underplating during the CAMP event. After the intense short‐period CAMP activity ceased in the early Jurassic, rifting along the Hartford basin continued for another 5–10 million years (Withjack et al, 2012), which may have resulted in further thinning of the previously underplated crust.…”

Section: Discussionmentioning

confidence: 99%

Section: 1029/2020gl089316mentioning

confidence: 99%

“…The relative timing of CAMP and extension in the Hartford basin is different than in some other ENAM rift basins, particularly in the southeastern United States, where CAMP magmatism postdates the deposition of synrift sediments (e.g., Withjack et al, 1998). Recent receiver function studies (Li et al, 2018; Long et al, 2018) revealed a west‐to‐east decrease in the depth of Moho of up to 15 km near the western boundary of the Hartford basin. This geological setting makes the Hartford basin an ideal target to study the spatial distribution of magmatic intrusion within the crust, the role of magmatism in continental rifting, and the interplay between extension and magmatism beneath southern New England.…”

Section: Introductionmentioning

confidence: 99%

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Seismic Evidence for Crustal Modification Beneath the Hartford Rift Basin in the Northeastern United States

Gao

Yang

Long

et al. 2020

Geophysical Research Letters

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Extensive Mesozoic rifting along the eastern North American margin formed a series of basins, including the Hartford basin in southern New England. Nearly contemporaneously, the geographically widespread Central Atlantic Magmatic Province (CAMP) was emplaced. The Hartford basin provides an ideal place to investigate the roles of rifting and magmatism in crustal evolution, as the integration of the dense SEISConn array and other seismic networks provides excellent station coverage. Using full‐wave ambient noise tomography, we constructed a detailed crustal model, revealing a low‐velocity (Vs = 3.3–3.6 km/s) midcrust and a high‐velocity (Vs = 4.0–4.5 km/s) lower crust beneath the Hartford basin. The low‐velocity midcrust may correspond to a layer of radial anisotropy due to extension and crustal thinning during rifting. The high‐velocity crustal root likely represents the remnant of magmatic underplating resulting from the CAMP event. Our findings shed light on crustal modification associated with supercontinental breakup, rifting, extension, and magmatism.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: 1029/2020gl089316mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Seismic Evidence for Crustal Modification Beneath the Hartford Rift Basin in the Northeastern United States

Gao

Yang

Long

et al. 2020

Geophysical Research Letters

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Probing the Structure of the Crust and Mantle Lithosphere beneath the Southern New England Appalachians via the SEISConn Deployment

Long

Aragon

2020

Seismological Research Letters

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Abstract The eastern margin of North America has been affected by a range of fundamental tectonic processes in the geologic past. Major events include the Paleozoic Appalachian orogeny, which culminated in the formation of the supercontinent Pangea, and the breakup of Pangea during the Mesozoic. The southern New England Appalachians exhibit a particularly rich set of geologic and tectonic structures that reflect multiple episodes of subduction and terrane accretion, as well as subsequent continental breakup. It remains poorly known, however, to what extent structures at depth in the crust and lithospheric mantle reflect these processes, and how they relate to the geological architecture at the surface. The Seismic Experiment for Imaging Structure beneath Connecticut (SEISConn) was a deployment of 15 broadband seismometers in a dense linear array across northern Connecticut. The array traversed a number of major tectonic boundaries, sampling across the Laurentian margin in its western portion to the Avalonian terrane at its eastern end. It also crossed the Hartford rift basin in the central portion of the state. The SEISConn stations operated between 2015 and 2019; data from the experiment are archived at the Incorporated Research Institutions for Seismology Data Management Center and will be publicly available beginning in 2021. A suite of imaging techniques is being applied to SEISConn data, with the goal of providing a detailed view of the crust and mantle lithosphere (including discontinuities, seismic velocities, and seismic anisotropy) beneath the southern New England Appalachians. Results from these analyses will inform a host of fundamental scientific questions about the structural evolution of orogens, the processes involved in continental rifting, and the nature of crustal and mantle lithospheric deformation during subduction, terrane accretion, and continental breakup.

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The “Passive” Margin of Eastern North America: Rifting and the Influence of Prerift Orogenic Activity on Postrift Development

Withjack

Malinconico²,

Durcanin

et al. 2020

Lithosphere

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We have analyzed and synthesized geologic and geophysical data from the onshore Newark rift basin and adjacent onshore and offshore basins to better understand the Mesozoic development of the eastern North American rift system and passive margin. Our work indicates that rifting had three phases: (1) an initial, prolonged phase of extension and subsidence; (2) a short-lived phase with higher rates of extension and subsidence, intrabasin faulting, and intense magmatism; and (3) a final phase with limited subsidence and deposition. Additionally, our work shows that anomalous uplift and erosion, associated with crustal-scale arching/warping subparallel to the prerift and syn-rift crustal fabric not the continent-ocean boundary, affected a region landward of the basement hinge zone. Uplift and erosion began during the final rifting phase and continued into early drifting with erosion locally exceeding 6 km. Subsequent subsidence was minimal. We propose that denudation unloading related to relic, prerift orogenic crustal thickness and elevated topography triggered the anomalous uplift and erosion. After the Paleozoic orogenies, postorogenic denudation unloading (cyclic erosion and isostatic rebound/uplift) significantly thinned the thickened crust and reduced topographic elevation. During rifting, extension stretched and tectonically thinned the crust, promoting widespread subsidence and deposition that dampened the postorogenic cycle of erosion and isostatic rebound/uplift. During the rift-drift transition, with extension focused near the breakup site, denudation unloading resumed landward of the basement hinge zone, producing significant erosion and uplift (related to isostatic rebound), crustal thinning, and topographic decay that left behind only eroded remnants of the once massive rift basins.

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Modification of Lithospheric Structure Beneath Connecticut via Subduction, Terrane Accretion, and Rifting: Insights From the Seisconn Experiment

Cited by 3 publications

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Seismic Evidence for Crustal Modification Beneath the Hartford Rift Basin in the Northeastern United States

Seismic Evidence for Crustal Modification Beneath the Hartford Rift Basin in the Northeastern United States

Probing the Structure of the Crust and Mantle Lithosphere beneath the Southern New England Appalachians via the SEISConn Deployment

The “Passive” Margin of Eastern North America: Rifting and the Influence of Prerift Orogenic Activity on Postrift Development

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