Preserved Neoproterozoic Continental Collision in Southeastern North America: The Brunswick Suture Zone and Osceola Continental Margin Arc
Abstract A series of exotic terranes were accreted to the eastern margin of southeastern Laurentia beginning in the Siluro‐Devonian (Acadian event), and to the northeastern Laurentian margin beginning earlier (late Taconian). Many of these terranes have unclear tectonostratigraphic relationships to each other and to their parental cratons, but their accretionary history is critical to understanding the evolution of the Appalachian orogen. Two of these, the Gondwanan Suwannee and Charleston terranes, accreted during the Alleghanian orogeny and now lie beneath the Atlantic Coastal Plain in southeastern North America. Reanalysis of deep seismic reflection and well data reveals a preserved Neoproterozoic continental collision zone and associated continental margin arc, the Osceola arc, related to their juxtaposition. The subduction zone and associated strain are recorded in the newly termed Brunswick suture zone (BSZ). The BSZ is readily identified on a series of eight deep seismic reflection transects across the Brunswick Magnetic Anomaly (BMA), which we interpret as the boundary between the Charleston and Suwannee terranes. While originally interpreted to be the Late Paleozoic Alleghanian suture, new age constraints provided by the overlapping Gondwanan Paleozoic Suwannee Basin strata require the BSZ to predate the Early to Middle Paleozoic passive margin sequence of the Suwannee Basin. These results provide new insights into the tectonostratigraphic evolution of the Charleston and Suwannee terranes, the controversy surrounding the age and origin of the dipping seismic reflectors, previously attributed to the suturing of the Suwannee terrane to Laurentia, and the relationship of this suture zone to the origin of the BMA.
- Research Organization:
- Southern States Energy Board, Peachtree Corners, GA (United States)
- Sponsoring Organization:
- USDOE Office of Fossil Energy (FE)
- Grant/Contract Number:
- FE0026086; DE‐FE0026086, CFDA 81.089
- OSTI ID:
- 1537333
- Alternate ID(s):
- OSTI ID: 1418725
- Journal Information:
- Tectonics, Vol. 37, Issue 1; ISSN 0278-7407
- Publisher:
- Wiley/American Geophysical Union (AGU)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
From the Alleghanian to the Atlantic: Extensional collapse of the southernmost Appalachian orogen
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journal | February 2019 |
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