The case for dynamic subsidence of the U.S. east coast since the Eocene

• Published in: Geophysical research letters Vol. 35; no. 8; pp. L08305 - n/a
• Main Authors: Spasojević, Sonja, Liu, Lijun, Gurnis, Michael, Müller, R. Dietmar
• Format: Journal Article
• Language: English
• Published: Washington, DC American Geophysical Union 01.04.2008; Blackwell Publishing Ltd
• Subjects: Cenozoic; Continental tectonics; dynamic subsidence; Dynamics of lithosphere and mantle; Earth sciences; Earth, ocean, space; Exact sciences and technology; geodynamic models; Geographic Location; Global Change; Information Related to Geologic Time; North America; sea level; Sea level change; Tectonophysics; United States; New Jersey; ANW, USA, New Jersey; dynamic subsidence; sea level; geodynamic models; Neogene; Paleogene; plates; Position; Tertiary; Regional scope; upper Tertiary; Adjoint method; Eocene; global; North America; land subsidence; convection; dynamics; coastal plains; tomography; subsidence; mantle; Miocene; Cenozoic; Phanerozoic; Dynamic model
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2008GL033511

The dynamic subsidence of the United States east coast is addressed using the discrepancy between regional and global estimates of sea level, elevation of paleoshorelines, and adjoint models of mantle convection that assimilate plate motions and seismic tomography. The positions of Eocene and Miocene paleoshorelines are lower than predicted by global sea levels, suggesting at least 50 m, and possibly as much as 200 m of subsidence since the end of the Eocene. Dynamic models predict subsidence of the east coast since the end of Eocene, although the exact magnitude is uncertain. This subsidence has been occurring during an overall global sea‐level fall, with the eustatic change being larger than the dynamic subsidence; this results in a regional sea‐level fall in the absence of land subsidence. Dynamic subsidence is consistent with the difference between eustasy and regional sea level at the New Jersey coastal plain.