干旱区生态环境知识资源中心(Arid): Anatomy of the Book Canyon conglomerate: a sequence boundary at the top of the Bear Gulch Limestone in the Big Snowy Trough

Arid

DOI	10.1007/s10347-019-0557-4
	Anatomy of the Book Canyon conglomerate: a sequence boundary at the top of the Bear Gulch Limestone in the Big Snowy Trough
	Singer, Amy 1; Stanley, George D.2; Hinman, Nancy W.1
通讯作者	Singer, Amy
来源期刊	FACIES
ISSN	0172-9179
EISSN	1612-4820
出版年	2019
卷号	65 期号:2
英文摘要	The Serpukhovian Book Canyon Conglomerate is an unpublished limestone conglomerate contained within the Tyler Formation in central Montana. It overlies and contains clasts of the Bear Gulch Limestone, a plattenkalk deposit yielding amazing paleontological detail. The Book Canyon Conglomerate is up to 2m thick, markedly lensoid, and laterally discontinuous in its outcrop for a distance of 2km but likely extends beyond the study area. Well logs and cores indicate its presence in the subsurface between the underlying Bear Gulch Limestone (Serpukhovian) and overlying Tyler Formation (Serpukhovian-Morrowan). This conglomerate provides new information regarding the transition of the marine-dominated Bear Gulch Limestone to the overlying Tyler Formation. The Book Canyon Conglomerate is dominantly clast-supported and includes sedimentary structures including pebble and cobble imbrication, tangential cross-stratification, and an overall upward-fining character. The basal surface of the conglomerate is sharp and irregular where the top of the underlying Bear Gulch Limestone has been erosionally removed. The Book Canyon Conglomerate is therefore interpreted as a fluvial channel deposit formed on a surface of subaerial exposure at the top of the Bear Gulch Limestone. In areas where the conglomerate is thin or absent, the top of the Bear Gulch Limestone is interpreted as a paleosol developed in a semi-arid climate where it is preserved between channel incisions of the Book Canyon Conglomerate. The paleosol contains microcrystalline silica cement and limestone clasts that have weathered to a black color. Freshwater exposure and channelized fluvial erosion early in the post-depositional history of the Bear Gulch Limestone explain variations in the contacts between units. These variations contribute to the debate concerning stratigraphic relationships. Further analysis of unconformities and fauna at the base and top of the unit clarifies the Bear Gulch Limestone's position in time, and its relationship to the Heath and Tyler Formations.
英文关键词	Plattenkalk Lagerstatte Bear Gulch Book Canyon Heath Tyler Serpukhovian Montana Conglomerate
类型	Article
语种	英语
国家	USA
收录类别	SCI-E
WOS记录号	WOS:000459426100001
WOS关键词	PLATTENKALK
WOS类目	Geology ; Paleontology
WOS研究方向	Geology ; Paleontology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/215620
作者单位	1.Univ Montana, Dept Geosci, 32 Campus Dr 1296, Missoula, MT 59812 USA; 2.Univ Montana, Paleontol Ctr, Missoula, MT 59812 USA
推荐引用方式 GB/T 7714	Singer, Amy,Stanley, George D.,Hinman, Nancy W.. Anatomy of the Book Canyon conglomerate: a sequence boundary at the top of the Bear Gulch Limestone in the Big Snowy Trough[J],2019,65(2).
APA	Singer, Amy,Stanley, George D.,&Hinman, Nancy W..(2019).Anatomy of the Book Canyon conglomerate: a sequence boundary at the top of the Bear Gulch Limestone in the Big Snowy Trough.FACIES,65(2).
MLA	Singer, Amy,et al."Anatomy of the Book Canyon conglomerate: a sequence boundary at the top of the Bear Gulch Limestone in the Big Snowy Trough".FACIES 65.2(2019).