Ladogian Series

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Ladogian Series

 

(named after Lake Ladoga), one of the Precambrian series. It was identified by the Finnish geologist J. Sederholm in 1897. On the bottom it is composed of amphibolite shales, amphibolites, metaeffusives, and marbles; on the top are biotite shales and biotite-quartzes. Some varieties of dark-colored shales with strata of coarse detritus resemble slaty formations. The Ladogian series is cut by granites that are 1,950,000,000 years old.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.