Seismic Evidence for Crustal Magmatic Intrusion Beneath the Southern Part of the Eastern North American Margin

Li, Cong1; Yu, Chunquan1,2

2024-05-01

10.1029/2023JB028143

JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH   影响因子和分区

2169-9313

2169-9356

["The southern portion of the eastern North American margin (SENAM) is an archetypical volcanic passive margin formed during Mesozoic rifting. How past magmatic events affect the evolution of the SENAM remains an open question of fundamental importance. To better understand this question, here we construct a high-resolution 3-D crustal velocity model from the oceanic side to the continental interior with a combination of multimodal dispersion inversion and full-waveform ambient noise tomography. Our new model reveals an oceanic-continental transitional crust over a short horizonal distance of 100-150 km across the SENAM, with a local-scale lower-than-surrounding velocity anomaly directly beneath the transitional crust. Furthermore, the new model shows three intra-crustal higher-than-average velocity anomalies beneath the SENAM continent. We suggest that the magmatism assisted the Mesozoic rifting process to form the narrow ocean-continent transitional crust along the coastline. The underplating of magma beneath the transitional crust led to a reduction of seismic velocity of the uppermost mantle. In addition, it is probable that the emplacement of the Central Atlantic Magmatic Province caused widespread magmatic intrusions within the continental crust of the SENAM, which were later solidified into intra-crustal high-velocity plutons. Our findings provide new insights into crustal modification history at the passive margin.","It has been suggested that the emplacement of magma played a key role in the formation and evolution of passive margins. However, how this process evolves during geological time is still unclear. The southern portion of the eastern North American margin (SENAM) preserved many magmatic records, making it an ideal laboratory to study this question. In this study, we constructed a high-resolution 3-D crustal velocity model from the oceanic side to the continental interior of the SENAM using a combination of state-of-the-art multimodal dispersion inversion and full-waveform ambient noise tomography. Our new model reveals two important features within the crust and upper mantle of the SENAM: (a) a sharp increase in crustal thickness over a transitional zone from ocean to continent, and a lower-than-surrounding velocity anomaly beneath the eastern margin of the transitional crust; and (b) three higher-than-average velocity anomalies within the continental crust. We suggest that the magmatic events assisted a continental rifting at similar to 200 Ma in forming the ocean-continent transitional crust. In addition, the magma associated with the emplacement of Central Atlantic Magmatic Province might have been injected into the continental crust of the SENAM, which subsequently solidified into high-velocity igneous rocks.","A high-resolution 3-D crustal velocity model is constructed in the southern portion of the eastern North American margin A transitional crust is observed from ocean to continent that was likely formed by a magmatic-assisted continental rifting Three high velocity anomalies are observed within the continental crust, probably representing magmatic intrusion associated with Central Atlantic Magmatic Province"]

crustal structures magmatic intrusion the eastern North American margin multimodal dispersion inversion full-waveform ambient noise tomography

SCI

英语

第一 ; 通讯

China Postdoctoral Science Foundation[2022M711473] ; Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology[2022B1212010002] ; null[42104052] ; null[41974043] ; null[42174058]

Geochemistry & Geophysics

Geochemistry & Geophysics

WOS:001233336500001

AMER GEOPHYSICAL UNION

GEOSCIENCES

Web of Science

1.Southern Univ Sci & Technol, Dept Earth & Space Sci, Shenzhen, Peoples R China
2.Southern Univ Sci & Technol, Guangdong Prov Key Lab Geophys High resolut Imagin, Shenzhen, Peoples R China

Li, Cong,Yu, Chunquan. Seismic Evidence for Crustal Magmatic Intrusion Beneath the Southern Part of the Eastern North American Margin[J]. JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,2024,129(5).

Li, Cong,&Yu, Chunquan.(2024).Seismic Evidence for Crustal Magmatic Intrusion Beneath the Southern Part of the Eastern North American Margin.JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,129(5).

Li, Cong,et al."Seismic Evidence for Crustal Magmatic Intrusion Beneath the Southern Part of the Eastern North American Margin".JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 129.5(2024).