Fusulinids from slope debris flow beds in the Word Formation (Guadalupian, Middle Permian), Gilleland Canyon, northwestern Glass Mountains, West Texas

Three Guadalupian allochthonous debris flow beds in a slope-to-basin facies succession in northern Gilleland Canyon of the northwest Glass Mountains were sampled for fusulinid biostratigraphic age-dating. The deeper water allochthonous debris flow beds underlie the shelf-margin packstone-grainstone facies of the Willis Ranch Member of the Word Formation (3rd Word Limestone Bed of King 1931) (middle Guadalupian, early Wordian), which forms a distinct bench all along the west wall of Gilleland Canyon (114–169m above base of measured section). The uppermost GV-RC1 sample, from 104 m in the measured section, contained the fusulinids Parafusulina sellardsi, P. antimonioensis, P. deliciasensis, P. rothi, P. trumpyi, and P. boesei. SampleGV-CM1, from 83min the section, contained P. sellardsi, P. deliciasensis, P. rothi, P. boesei, and P. lineata. The lowest sample GV-CM20, from 76 m in the section, contained only P. deliciasensis and P. wildei. According to previous studies, most of these species appear in Roadian-aged strata and range upward into early Wordian-aged strata, but the common occurrence of P. sellardsi in the upper two samples, and the occurrence of P. antimonioensis in the uppermost sample confirm an early Wordian age.