User:IveGoneAway/sandbox/Abilene conglomerate
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The Abilene conglomerate is an informal Pleistocene unit of sand and gravel "cemented by calcarous matter".[4] Here and there are redish sandstone and yellowish chalk cobbles. Outcrops of this mortar bed are found along tributaries of the Smoky Hill River in the vicinity of Abilene and Solomon, Kansas. Pioneering geologists, including F.B. Meek, F.V. Hayden,[4] E. Haworth,[3] C.S. Prosser,[2] and R.C. Moore [5] each reported on the unusual nature of the conglomerate. At that time, each identified or accepted that the unit formed in the Permian, like all of the shale and limestone in the surrounding hills. In particular, Meek and Hayden observed that the unusual conglomerate bed appeared to lie just at the top of the beds of rich Permian marine fossils and repetative massive limestone beds but also just at the base of similar shale that had no fossils or massive limestones (such as they could recognise then). Later geologists would determine that this change in the rock patterns marked the very last of the open marine cycles and the beginning of salt lake sequences.
Abilene conglomerate | |
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Stratigraphic range: Pleistocene | |
Type | Geologic bed |
Underlies | Later Pleistocene glacial loess or dunes |
Overlies | Eroded slopes of Wellington Shale (most commonly) |
Lithology | |
Primary | Calcareous conglomerate of sand and gravel |
Other | Diagnostic pebbles and cobbles of sandstone and mudstone from the Dakota Formation, chalk from the Greenhorn Formation, and distinctive scattered quartz and quartzite presumed from the Rocky Mountains |
Location | |
Coordinates | 38.87232°N 97.19456°W / 38.87232; -97.19456 |
Region | Kansas |
Country | United States |
Type section | |
Named for | Abilene, Kansas[1] |
Named by | C.S. Prosser[2] |
Location | Turkey Creek, Dickinson County, Kansas[3] |
Year defined | 1895 |
Coordinates | 38.87232°N 97.19456°W / 38.87232; -97.19456 |
Moore eventually recognized that the conglomerate was much more recent than the Permian bedrock, inferring that the conglomerate formed only after the Kansas River and Smoky Hill River finished cutting down through all of the Permian layers found in Kansas (between Saline and Riley counties, all of the Kansas Permian is exposed.
Today, this conglomerate bed is thought to be possibly related to the lower, cemented conglomerate found within the McPherson Equus Beds to the southwest.[6][7]
Some geologist attempted to label the unit as Abilene limestone, in part to reflect the calcareous nature of the outcrop at Abilene, but also to explain how they thought that the conglomerate they could find only in valley side was weathered Permian Hollenberg dolomite.[8]