Re: glauconite

Arthur V. Chadwick (
Thu, 05 Feb 1998 08:58:21 -0800

At 10:39 AM 2/5/98 -0400, David wrote:
>"Far from sources of sediment" can occur in shallow water, as long as a
>muddy river is not too close. Likewise, glauconite forms typically in
>pores in the sediment, so the oxygenation of the water column is

I am still looking for examples of modern formation in shallow water.
Every source I have been able to find gives deep water as the normative
habitat for glauconite formation. Even if some were formed in "shallow"
water, this is not the normal environment for formation, and glauconite
remains, in my opinion, a good indicator for water depths in excess of 100
meters. The burden of proof is on those who would make glauconite
containing sediments shallow water deposits. In the case of the
glauconitic Tapeats, on the basis of a lot of other evidence, it is not a
shallow water deposit, and this calls into question glauconitic sands
reported on the basis of sed structures to be shallow marine.