干旱区生态环境知识资源中心(Arid): The Late Palaeozoic Ice Age unconformity in southern Namibia viewed as a patchwork mosaic

Arid

DOI	10.1002/dep2.163
	The Late Palaeozoic Ice Age unconformity in southern Namibia viewed as a patchwork mosaic
	Le Heron, Daniel P.; Kettler, Christoph; Griffis, Neil P.; Dietrich, Pierre; Montanez, Isabel P.; Osleger, David A.; Hofmann, Axel; Douillet, Guilhem; Mundil, Roland
通讯作者	Le Heron, DP (corresponding author), Univ Wien, Inst Geol, Althanstr 14, A-1190 Vienna, Austria.
来源期刊	DEPOSITIONAL RECORD
EISSN	2055-4877
出版年	2021-09
英文摘要	The expansion of ice masses across southern Africa during the Late Palaeozoic Ice Age has been known for 150 years, including the distribution of upland areas in controlling the configuration of glaciation. In Namibia, increasing attention has focussed on long and deep palaeovalley networks in the Kaokoland region in the north, but comparatively little work has been attempted in the topographically subdued plains of the south, in the Aranos and Karasburg basins. The desert terrain of the Aranos area exposes diamictites of the Dwyka Group discontinuously over about 300 km, extending further south to the Karasburg area at the Namibian-South African border along the Orange River. Whilst examined at a stratigraphic level, the nature of the contact between the Dwyka glacial rocks and underlying lithologies has not been systematically investigated. This paper presents the results from fieldwork in austral winter 2019, in which a highly varying basal contact is described that records the processes of growth, flow and expansion of ice masses across this part of Gondwana. At the basin margins, subglacially produced unconformities exhibit classic glacially striated pavements on indurated bedrock. In comparison, the basal subglacial unconformity in the more basinward regions is characterised by soft-sediment striated surfaces and deformation. In the Aranos Basin, soft-sediment shear zones originated in the subglacial environment. This type of subglacial unconformity developed over well-differentiated, unconsolidated, siliciclastic materials. Where ice advanced over more poorly sorted material or cannibalised pre-existing diamictites, 'boulder-pavements' recognised as single clast-thick boulder-dominated intervals formed. Importantly, these boulder-pavements are enriched in clasts, which were facetted and striated in-situ by overriding ice. By integrating measurements of striation orientations, fold vergence and palaeocurrent information, former ice flow pathways can potentially be reconstructed over a wide area.
英文关键词	glacial ice sheets Late Palaeozoic
类型	Article ; Early Access
语种	英语
开放获取类型	gold, Green Submitted
收录类别	SCI-E
WOS记录号	WOS:000700825800001
WOS关键词	PARANA BASIN ; KAROO ; GLACIATION ; STRATIGRAPHY ; DEFORMATION ; PROVENANCE ; SEQUENCES ; DEPOSITS ; AFRICA ; TUFFS
WOS类目	Geology
WOS研究方向	Geology
来源机构	University of California, Davis ; E17
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/362932
作者单位	[Le Heron, Daniel P.; Kettler, Christoph] Univ Wien, Inst Geol, Althanstr 14, A-1190 Vienna, Austria; [Griffis, Neil P.; Montanez, Isabel P.; Osleger, David A.] Univ Calif Davis, Earth & Phys Sci, Davis, CA 95616 USA; [Dietrich, Pierre] Univ Rennes 1, Geosci Rennes, UMR6118, Rennes, France; [Hofmann, Axel] Univ Johannesburg, Dept Geol, Johannesburg, South Africa; [Douillet, Guilhem] Inst Geol, Bern, Switzerland; [Mundil, Roland] Berkeley Geochronol Ctr, Berkeley, CA USA
推荐引用方式 GB/T 7714	Le Heron, Daniel P.,Kettler, Christoph,Griffis, Neil P.,et al. The Late Palaeozoic Ice Age unconformity in southern Namibia viewed as a patchwork mosaic[J]. University of California, Davis, E17,2021.
APA	Le Heron, Daniel P..,Kettler, Christoph.,Griffis, Neil P..,Dietrich, Pierre.,Montanez, Isabel P..,...&Mundil, Roland.(2021).The Late Palaeozoic Ice Age unconformity in southern Namibia viewed as a patchwork mosaic.DEPOSITIONAL RECORD.
MLA	Le Heron, Daniel P.,et al."The Late Palaeozoic Ice Age unconformity in southern Namibia viewed as a patchwork mosaic".DEPOSITIONAL RECORD (2021).