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Microbial abundance in the deep subsurface of the Chesapeake Bay impact crater: relationship to lithology and impact processes

GSA Special Papers

By:
, , , , , , , , , and
DOI: 10.1130/2009.2458(40)

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Abstract

Asteroid and comet impact events are known to cause profound disruption to surface ecosystems. The aseptic collection of samples throughout a 1.76-km-deep set of cores recovered from the deep subsurface of the Chesapeake Bay impact structure has allowed the study of the subsurface biosphere in a region disrupted by an impactor. Microbiological enumerations suggest the presence of three major microbiological zones. The upper zone (127–867 m) is characterized by a logarithmic decline in microbial abundance from the surface through the postimpact section of Miocene to Upper Eocene marine sediments and across the transition into the upper layers of the impact tsunami resurge sediments and sediment megablocks. In the middle zone (867–1397 m) microbial abundances are below detection. This zone is predominantly quartz sand, primarily composed of boulders and blocks, and it may have been mostly sterilized by the thermal pulse delivered during impact. No samples were collected from the large granite block (1096–1371 m). The lowest zone (below 1397 m) of increasing microbial abundance coincides with a region of heavily impact-fractured, hydraulically conductive suevite and fractured schist. These zones correspond to lithologies influenced by impact processes. Our results yield insights into the influence of impacts on the deep subsurface biosphere.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Microbial abundance in the deep subsurface of the Chesapeake Bay impact crater: relationship to lithology and impact processes
Series title:
GSA Special Papers
DOI:
10.1130/2009.2458(40)
Issue:
458
Year Published:
2009
Language:
English
Publisher:
Geological Society of America
Contributing office(s):
National Research Program - Eastern Branch
Description:
10 p.
First page:
941
Last page:
950
Country:
United States
State:
Virginia
Other Geospatial:
Chesapeake Bay
Online Only (Y/N):
N
Additional Online Files(Y/N):
N