Fossil Cold Seep
(c) 2005 Andrew Alden, licensed to About.com, Inc. (fair use policy)
A cold seep is a place on the sea floor where organic-rich fluids leak from the sediments below. Specialized microorganisms that live on sulfides and hydrocarbons thrive in the anaerobic environment, and other species make a living with their help. Cold seeps make up part of a global network of seafloor oases along with black smokers and whale falls.
Only recently have cold seeps been recognized in the fossil record. California's Panoche Hills has the largest set of fossil cold seeps found in the world so far. I say "so far" because these lumps of carbonates and sulfides have probably been seen and ignored by geologic mappers in many areas of sedimentary rocks.
This fossil cold seep is of early Paleocene age, about 65 million years old. It has an outer shell of gypsum, visible around the left base. Its core is a jumbled mass of carbonate rock containing fossils of tubeworms, bivalves and gastropods. Modern cold seeps are very much the same.
See more pictures from the Panoche Hills in the Coast Range wallpaper gallery.
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