Skip to main content

IMIS

A new integrated search interface will become available in the next phase of marineinfo.org.
For the time being, please use IMIS to search available data

 

[ report an error in this record ]basket (1): add | show Print this page

one publication added to basket [257668]
Fabric and formation of grapestone concretions within an unusual ancient methane seep system (Eocene, Bulgaria)
De Boever, E.; Birgel, D.; Muchez, P.; Peckmann, J.; Dimitrov, L.; Swennen, R. (2011). Fabric and formation of grapestone concretions within an unusual ancient methane seep system (Eocene, Bulgaria). Terra nova (Print) 23(1): 56-61. https://dx.doi.org/10.1111/j.1365-3121.2010.00984.x
In: Terra Nova. Blackwell: Oxford. ISSN 0954-4879; e-ISSN 1365-3121, more
Peer reviewed article  

Available in  Authors 

Authors  Top 
  • De Boever, E., more
  • Birgel, D.
  • Muchez, P., more
  • Peckmann, J.
  • Dimitrov, L.
  • Swennen, R., more

Abstract
    Authigenic carbonates at methane seeps provide valuable information on the evolution of seepage dynamics. In this study, we report on an unusual type of 13C-depleted [d13C: -44.8‰ to -8.3‰V-PDB (Vienna PeeDee Belemnite)] calcite-cemented grapestone concretion composed of small spheroidal nodules, <0.1–15 cm across, associated with an ancient seep setting in Eocene marine sediments (Pobiti Kamani area, NE Bulgaria). Field observations suggest that the nodules started to grow close to the ancient sea floor and apparently were agitated by fluid flow, promoting their spheroidal shape. The precipitation of calcite between sand grains started at multiple closely spaced nucleation sites, induced by locally elevated calcite supersaturation in response to anaerobic microbial consumption of ascending methane. Consecutive nodule growth continued deeper in the sediment, with the formation of dark and light concentric bands surrounding one or more nodule cores. The occurrence of similar grapestone concretions at seeps might indicate changing redox conditions at the seep site.

All data in the Integrated Marine Information System (IMIS) is subject to the VLIZ privacy policy Top | Authors