Sediment-routing controls on sandstone bulk petrographic composition and texture across an ancient shelf: example from Cretaceous Western Interior Basin, Utah and Colorado, USA
File(s)
Accepted version
Author(s)
Lupin, janifar
Hampson, Gary
Type
Journal Article
Abstract
Sediment-routing controls on sandstone texture and bulk petrography have been evaluated in linked alluvial-coastal-shelfal deposits of the Upper Cretaceous Castlegate Sandstone, Blackhawk Formation, Star Point Sandstone, and Mancos Shale (Western Interior Basin, Utah and Colorado, USA) using thin-section analysis of representative outcrop samples in the context of a high-resolution sequence stratigraphic and paleogeographic framework. The studied strata record deposition from two styles of sediment-routing system within an overfilled foredeep and contiguous intra-continental seaway. First, multiple transverse drainages supplied sand to fluvial, shoreline, and shelf segments of sediment-routing systems characterized by down-dip transport distances of 150-450 km and significant strike-oriented sediment transport along the shoreline. Second, the distal shoreline-shelf segment of an axially supplied sediment-routing system was characterized by sand transport for a distance of c. 300 km.
Bulk petrographic composition indicates that transverse sediment-routing systems were sourced from catchments that supplied quartz-rich sand with a subordinate lithic component, while the large axial sediment-routing system was sourced from a catchment(s) supplying slightly more feldspathic sand. Thin-section measurements of mean grain size, sorting, skewness, and ratio of minimum-to-maximum diameter (a proxy for sphericity) are similar for sandstones deposited in fluvial, shoreline and shelf segments of the transverse sediment-routing systems and in the shoreline-shelf segment of the axial sediment-routing systems, although hydrodynamic sorting is important in locally segregating grain-size populations within each segment. Further, textural analysis of detrital quartz, feldspar, and lithic sand-grain populations shows little evidence of relative change in mean grain size or apparent grain sphericity with downsystem distance, implying that sand-grain populations of different petrographic composition did not undergo significant differential mechanical breakdown during transport. Instead, the textural characteristics of these sand-grain populations are inferred to have been controlled mainly by bedrock lithology and recycling in source catchments. The textural signal of sediment-source areas then propagated downsystem in the sand fraction of detrital sediment supply. This inference is supported by the fine- to medium-grained, well- to very well-sorted character of all sandstone samples, consistent with recycling of sandstones and quartzites from the Sevier fold-and-thrust belt.
Bulk petrographic composition indicates that transverse sediment-routing systems were sourced from catchments that supplied quartz-rich sand with a subordinate lithic component, while the large axial sediment-routing system was sourced from a catchment(s) supplying slightly more feldspathic sand. Thin-section measurements of mean grain size, sorting, skewness, and ratio of minimum-to-maximum diameter (a proxy for sphericity) are similar for sandstones deposited in fluvial, shoreline and shelf segments of the transverse sediment-routing systems and in the shoreline-shelf segment of the axial sediment-routing systems, although hydrodynamic sorting is important in locally segregating grain-size populations within each segment. Further, textural analysis of detrital quartz, feldspar, and lithic sand-grain populations shows little evidence of relative change in mean grain size or apparent grain sphericity with downsystem distance, implying that sand-grain populations of different petrographic composition did not undergo significant differential mechanical breakdown during transport. Instead, the textural characteristics of these sand-grain populations are inferred to have been controlled mainly by bedrock lithology and recycling in source catchments. The textural signal of sediment-source areas then propagated downsystem in the sand fraction of detrital sediment supply. This inference is supported by the fine- to medium-grained, well- to very well-sorted character of all sandstone samples, consistent with recycling of sandstones and quartzites from the Sevier fold-and-thrust belt.
Date Issued
2020-12-11
Date Acceptance
2020-07-20
Citation
Journal of Sedimentary Research, 2020, 90 (10), pp.1389-1409
ISSN
1527-1404
Publisher
Society for Sedimentary Geology (SEPM)
Start Page
1389
End Page
1409
Journal / Book Title
Journal of Sedimentary Research
Volume
90
Issue
10
Copyright Statement
© 2020, SEPM (Society for Sedimentary Geology)
Identifier
https://pubs.geoscienceworld.org/sepm/jsedres/article/90/10/1389/593115/Sediment-routing-controls-on-sandstone-bulk
Subjects
0403 Geology
Geology
Publication Status
Published
Date Publish Online
2020-12-11