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Evidence for high salinity of Early Cretaceous sea water from the Chesapeake Bay crater

Nature

By:
, , , , and
DOI: 10.1038/nature12714

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Abstract

High salinity groundwater more than 1000 metres deep in the Atlantic Coastal Plain of the United States has been documented in several locations1,2, most recently within the 35 million-year-old Chesapeake Bay impact crater3,4,5. Suggestions for the origin of increased salinity in the crater have included evaporite dissolution6, osmosis6, and evaporation from heating7 associated with the bolide impact. Here we present chemical, isotopic and physical evidence that together indicate that groundwater in the Chesapeake crater is remnant Early Cretaceous North Atlantic (ECNA) seawater. We find that the seawater is likely 100-145 million years old and that it has an average salinity of about 70 per mil, which is twice that of modern seawater and consistent with the nearly closed ECNA basin8. Previous evidence for temperature and salinity levels of ancient oceans have been estimated indirectly from geochemical, isotopic and paleontological analyses of solid materials in deep sediment cores. In contrast, our study identifies ancient seawater in situ and provides a direct estimate of its age and salinity. Moreover, we suggest that it is likely that remnants of ECNA seawater persist in deep sediments at many locations along the Atlantic margin.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Evidence for high salinity of Early Cretaceous sea water from the Chesapeake Bay crater
Series title:
Nature
DOI:
10.1038/nature12714
Volume
503
Issue:
745
Year Published:
2013
Language:
English
Publisher:
MacMillan Publishing Limited
Contributing office(s):
National Research Program - Eastern Branch
Description:
5 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Nature
First page:
252
Last page:
256
Number of Pages:
13
Country:
United States
State:
Maryl;Virginia