干旱区生态环境知识资源中心(Arid): Loess in eastern equatorial Pangea archives a dusty atmosphere and possible upland glaciation

Arid

DOI	10.1130/B35590.1
	Loess in eastern equatorial Pangea archives a dusty atmosphere and possible upland glaciation
	Pfeifer, Lily S.; Soreghan, Gerilyn S.; Pochat, Stephane; Van den Driessche, Jean
通讯作者	Pfeifer, LS (corresponding author), Univ Oklahoma, Sch Geosci, 100 East Boyd St, Norman, OK 73019 USA.
来源期刊	GEOLOGICAL SOCIETY OF AMERICA BULLETIN
ISSN	0016-7606
EISSN	1943-2674
出版年	2021
卷号	133 期号:1-2 页码:379-392
英文摘要	Carboniferous-Permian strata in basins within the Central Pangean Mountains in France archive regional paleoequatorial climate during a unique interval in geological history (Pangea assembly, ice-age collapse, megamonsoon inception). The voluminous (similar to 1.5 km) succession of exclusively fine-grained red beds that comprises the Permian Salagou Formation (Lodeve Basin, France) has long been interpreted to record either lacustrine or fluvial deposition, primarily based on a local emphasis of subaqueous features in the upper similar to 25% of the section. In contrast, data presented here indicate that the lower-middle Salagou Formation is dominated by up to 15-m-thick beds of internally massive red mudstone with abundant pedogenic features (microscale) and no evidence of channeling. Up-section, limited occurrences of ripple and hummocky cross-stratification, and mudcracks record the intermittent influence of shallow water, but with no channeling nor units with grain sizes exceeding coarse silt. These data suggest that the most parsimonious interpretation for the Salagou Formation involves eolian transport of the sediment and ultimate deposition as loess in shallow, ephemeral lacustrine environments. Provenance analyses of the Salagou Formation indicate coarse-grained protoliths and, together with geochemical proxies (chemical index of alteration [CIA] and tau(Na)) that correspond respectively to a low degree of chemical weathering and a mean annual temperature of similar to 4 degrees C, suggest that silt generation in this case is most consistent with cold-weathering (glacial and associated periglacial) processes in the Variscan highlands. Together with previous studies that detailed voluminous Permian loess in western equatorial Pangea, this work shows a globally unique distribution of dust at low latitudes that can be linked either directly to glaciated alpine terranes or to reworked and deflated deposits of other types (e.g., fluvial outwash) where fine-grained material was originally generated from glacial grinding in alpine systems. These results further support a revised model for early Permian climate, in which extratropical ice sheets coexisted with a semiarid tropics that may have hosted significant ice at moderate elevation.
类型	Article
语种	英语
开放获取类型	Green Published
收录类别	SCI-E
WOS记录号	WOS:000618060000026
WOS关键词	UPPER PALEOZOIC LOESSITE ; PERMIAN MAROON FORMATION ; SIZED QUARTZ SILT ; LODEVE BASIN ; GRAIN-SIZE ; DESERT LOESS ; WEATHERING PROFILES ; BODELE DEPRESSION ; WESTERN PANGAEA ; CLIMATE
WOS类目	Geosciences, Multidisciplinary
WOS研究方向	Geology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/350396
作者单位	[Pfeifer, Lily S.; Soreghan, Gerilyn S.] Univ Oklahoma, Sch Geosci, 100 East Boyd St, Norman, OK 73019 USA; [Pochat, Stephane] Univ Nantes, Lab Planetol & Geodynam, CNRS UMR 6112, 2 Rue Houssiniere, F-44000 Nantes, France; [Van den Driessche, Jean] Univ Rennes, Geosci Rennes UMR 6118, CNRS, F-35000 Rennes, France
推荐引用方式 GB/T 7714	Pfeifer, Lily S.,Soreghan, Gerilyn S.,Pochat, Stephane,et al. Loess in eastern equatorial Pangea archives a dusty atmosphere and possible upland glaciation[J],2021,133(1-2):379-392.
APA	Pfeifer, Lily S.,Soreghan, Gerilyn S.,Pochat, Stephane,&Van den Driessche, Jean.(2021).Loess in eastern equatorial Pangea archives a dusty atmosphere and possible upland glaciation.GEOLOGICAL SOCIETY OF AMERICA BULLETIN,133(1-2),379-392.
MLA	Pfeifer, Lily S.,et al."Loess in eastern equatorial Pangea archives a dusty atmosphere and possible upland glaciation".GEOLOGICAL SOCIETY OF AMERICA BULLETIN 133.1-2(2021):379-392.