Skip to main content
Advanced Search

Filters: Categories: Publication (X) > partyWithName: David B Loope (X)

3 results (67ms)   

View Results as: JSON ATOM CSV
At two stratigraphic intervals within the upper member of the Upper Pennsylvanian Hermosa Formation, calcareous eolian sand fills downward-tapering fissures that are as much as 18 cm wide and 5.7 m deep. Fissure fillings define orthogonal polygons 10 m or more in diameter. One of the host beds is primarily composed of subtidally deposited limestone, the other is a thinly laminated, nonmarine red siltstone. Both systems of fissure fillings are directly overlain and underlain by large-scale cross-stratified, calcareous eolianites. The limestone host bed contains chert pseudomorphs after gypsum. Compaction of host rocks contorted fissure fillings and caused doming of eolian strata over each fissure. Platy mineral grains...
Thin (< 30-cm-thick) sets of eolian cross-strata with irregular upper bounding surfaces make up 27% of the Lower Jurassic Wingate Sandstone near Moab in southeastern Utah and up to 40% of the Middle Jurassic Entrada Sandstone near Dinosaur National Monument in northeastern Utah. Deformation structures, interpreted as the tracks of large reptiles, are common in windripple laminae within and directly adjacent to these sets. Lithosomes composed primarily of these sets range from < 1 m to 9 m in thickness. Cosets composed of thick, trough cross-stratified sets that are interbedded with cosets composed of the thinner sets contain smooth, nearly horizontal bounding surfaces. The lack of intertonguing with thick sets of...
In Canyonlands National Park, south-east Utah, at least 29 partly exhumed, aligned sandstone ridges trending generally N20°W occur at the upper unconformable surface of the Lower Permian (Leonardian) White Rim Sandstone. The ridges are at least 1·5 km long, 250 m wide and have up to 14 m of vertical relief (mean of 9 m). A thin lag of coarse sandstone that contains wind-ripple laminae and granule ripples directly overlies the ridges. Angular blocks of sandstone within the lag and sand-filled fissures immediately below the lag, within the ridges, attest to early cementation of the ridge-forming material. SE-dipping aeolian cross-strata within the White Rim Sandstone and within the lag closely parallel the ridge...