the southwestern US were part of a larger post-glacial lake that covered much of the region near the end of the last glaciation. It is thought that at this time, conditions similar to that of the Ikka fjord allowed for the growth of massive ikaite. Isotope geochemistry Isotope geochemistry can reveal information about the origin of the elements that make up minerals. The isotopic composition of ikaite and the pseudomorphs is actively studied. Studies of the ratio of 13C to 12C in ikaite relative to a natural, standard ratio can help to determine the origin of the carbon pool (organic/inorganic) which was consumed to form ikaite. Some studies have shown that oxidizing methane is the source of both modern day ikaite and glendonites in high latitude, marine sediments. Similarly the ratio of 18O to 16O, which varies in nature with temperature and latitude, can be used to show that glendonites were formed in waters very close to the freezing point, in agreement with the observed formation of ikaite. References Further reading King, C., (1878). U. S. Geological exploration of the fortieth parallel, Vol. 1. Washington: D.C., U. S. Government Printing Office. Russell, I. C. (1889). Quaternary history of Mono Valley, California. Reprint from the Eighth Annual Report of the United States Geological Survey, Pages 267–394. Artemisia Press, Lee Vining, California 1984 External links Mineralogical and crystallographic data about ikaite Mineralogical and crystallographic data about ikaite Ikaite homepage Natural occurrences of ikaite Glendonites and pseudomorphs after ikaite (in German) Giant pseudomorphs after ikaite found on Moler Island, Jutland, Denmark Pyramidia – Lair of the Rare and Fascinating Glendonite A study of the type locality of the mineral ikaite Calcium minerals Carbonate minerals Monoclinic minerals Minerals in space group 15