Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published December 1983 | public
Journal Article

Evidence for primary aragonite precipitation, lower Proterozoic (1.9 Ga) Rocknest dolomite, Wopmay orogen, northwest Canada

Abstract

Abundant precipitation of aragonite is suggested by well-preserved fabrics in dolostones of the lower Proterozoic (1.9 Ga) Rocknest Formation. Fabrics include dolomite and silica after botryoidal aragonite in tepee structures and seafloor cement fans, and cement crusts in cryptalgal tufas. Aragonite was common on the 1.9-Ga Rocknest shelf, as it is on modern tropical shelves. A search for similar marine cement fabrics in other Precambrian carbonates should help resolve whether aragonite was an important precipitate from Precambrian tropical seas (implying an ocean carbonate chemistry similar to today), or if aragonite precipitation was restricted to rare times in the past, calcite (and even dolomite) being the main carbonates precipitated (as recently suggested by some authors).

Additional Information

© 1983 Geological Society of America. Manuscript received March 23, 1983; Revised manuscript received August 16, 1983; Manuscript accepted August 17, 1983. Financially supported by Geological Society of America Grant 2992-82, and a grant-in-aid from Sigma Xi. We thank Paul F. Hoffman and the Geological Survey of Canada for suggesting the Rocknest Shelf project to Grotzinger, and for providing logistic support in the field. S. Dorobek assisted with the microprobe analyses.

Additional details

Created:
August 22, 2023
Modified:
October 17, 2023