Applying sandstone modal composition and ImageJ analysis to constrain feldspar alteration in Early Permian (Wolfcampian) nonmarine strata in New Mexico

Abstract

Petrographic analysis of Early Permian, nonmarine strata of the Abo Formation (and equivalent strata) reveal a wide range in plagioclase and K-feldspar percentages and highly variable feldspar alteration trends throughout northern, central, and southern New Mexico. Sandstone modal composition trends show a significant decrease in detrital K-feldspar and increase in plagioclase as you compare percentages from northern (P=53%; K=47%), central (P=85%; K=15%), and southern New Mexico (P=97%; K=3%). In addition, elevated occurrences of diagenetic albite are in higher abundance in these strata in central and southern New Mexico compared to northern New Mexico.