Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 1 of 1
Full-Text Articles in Education
Storm Deposition Of Pisoids In The Humboldt Oolite Member Of The Gilmore City Formation (Mississippian), North-Central Iowa, Shawn C. Thomas, John R. Groves
Storm Deposition Of Pisoids In The Humboldt Oolite Member Of The Gilmore City Formation (Mississippian), North-Central Iowa, Shawn C. Thomas, John R. Groves
Journal of the Iowa Academy of Science: JIAS
Pisoids (concentrically laminated carbonate grains, > 2 mm in diameter) are abundant in the upper Humboldt Oolite Member of the Gilmore City Formation (Mississippian). Their cortices are isopachous and nuclei include both intraclasts and fragments of preexisting
pisoids. They occur both as floating grams m a fine grainstone matrix and concentrated at the bases of distinct layers that may be crudely graded beds. Sorting characteristics and the presence of broken and abraded pisoids suggest not only their origin as primary free grams, but also storm influence in the deposition of local pisolite layers. Regionally, the upper Humboldt Oolite is characterized by …