@article {shuck_role_2019,
	title = {The role of mantle melts in the transition from rifting to seafloor spreading offshore eastern North America},
	journal = {Earth and Planetary Science Letters},
	volume = {525},
	year = {2019},
	month = {nov},
	pages = {115756},
	abstract = {The Eastern North American Margin (ENAM) formed in the early Jurassic (\~{}195 Ma) with the breakup of supercontinent Pangea. This rifting event was accompanied by volcanism along the continental shelf of the eastern United States, giving rise to the East Coast Magnetic Anomaly (ECMA). Numerical models show that magmatic diking can assist rifting by reducing the effective stress required to rupture the lithosphere. Therefore, magma-rich rifts can develop a rapid transition from continental breakup to seafloor spreading. Alternatively, the onset of seafloor spreading may be accompanied by a long period of persistent thermal weakening and erosion of the lithosphere. In this paper we present analyses of active-source wide-angle seismic data collected during the 2014 ENAM Community Seismic Experiment in an area that extends farther offshore than previous seismic surveys along the eastern U.S. Seaward of the ECMA lies a zone of thin oceanic crust with high compressional seismic velocity (up to 7.5 km/s in the lower crust), whereas thicker normal oceanic crust lies \~{}200 km farther offshore along another prominent magnetic anomaly, the Blake Spur Magnetic Anomaly (BSMA). We reconcile our seismic images with a petrologic model to evaluate the mantle melting conditions during the late stages of continental breakup and early seafloor spreading in the Central Atlantic. We propose that the zone of thin crust between the ECMA and BSMA with high seismic velocity is best explained by the presence of a \~{}15{\textendash}20 km thick lithospheric lid at the time of early seafloor spreading, which prevented melting in the shallow mantle. Our analysis suggests that the volcanism that produced the nearshore ECMA did not lead to complete lithospheric breakup of the conjugate North American and African margins. Normal seafloor spreading began at the BSMA under a moderately high mantle potential temperature of \~{}1395{\textendash}1420{\textdegree}C, \~{}25 million years after the initial formation of the volcanic margin. These results imply that stretching, thermal weakening, and rupture of the lithosphere may take millions of years, even in the presence of mantle melts.},
	keywords = {continent-ocean transition, continental rifting, eastern North American margin, mantle melting, oceanic crust, seismic tomography},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2019.115756},
	url = {https://www.sciencedirect.com/science/article/pii/S0012821X19304480},
	author = {Shuck, Brandon D. and Van Avendonk, Harm J. A. and B{\'e}cel, Anne}
}
@article {dunn_crustal_2013,
	title = {Crustal construction and magma chamber properties along the Eastern Lau Spreading Center},
	journal = {Earth and Planetary Science Letters},
	volume = {371-372},
	year = {2013},
	month = {jun},
	pages = {112{\textendash}124},
	abstract = {The L-SCAN active-source seismic tomography experiment maps the crustal structure and magmatic system along a 120-km-long section of the back-arc Eastern Lau Spreading Center (ELSC), where the ridge undergoes abrupt changes in morphology and composition associated with increasing proximity to the Tofua volcanic arc. Using this dataset, we picked \textasciitilde197,000 P-wave travel times from 57 seismic airgun lines recorded at 83 ocean bottom seismograph stations, and inverted for a 3-D P-wave velocity image. The seismic images reveal a prominent, but narrow, seismic low velocity volume (LVV) located beneath all surveyed ridge segments, consistent with the high temperatures and melt of a crustal magmatic system. Crustal magmatic systems thus underlie spreading axes even where previous seismic reflection surveys did not detect magma lens reflectors, accounting for the heat source of high-temperature hydrothermal vents in these areas. The top of the LVV closely follows the ridge axis and steps across three overlapping spreading centers. As the offset of the overlap increases, the LVV becomes increasingly discontinuous across the ridge limbs. Surprisingly, the LVV is as much as twice as wide, but deeper, in the northern part of the ridge system where the crust is thinner, as compared to the LVV beneath the southern segments, where the crust is relatively thicker. The width of the LVV may be modulated by the degree of deep hydrothermal activity or temporal variations in melt supply, and thus may not correlate directly with the average melt flux as indicated by crustal thickness. Over the past 4Myr, the location of the ridge has swept across different mantle compositional domains, and the crust produced at the ridge formed a zoned pattern. The interpretation is that thick, highly porous, volcanic layers with felsic compositions cap regions of thick crust; thinner volcanic layers of basaltic composition cap regions of thinner crust. The zonal pattern indicates that the influence of slab-derived water on crustal construction has substantially decreased over time.},
	keywords = {back-arc basin, Eastern Lau Spreading Center, magma chamber, mantle melting, mid-ocean ridge, seismic tomography},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2013.04.008},
	url = {https://www.sciencedirect.com/science/article/pii/S0012821X13001891},
	author = {Dunn, Robert A. and Martinez, Fernando and Conder, James A.}
}
