干旱区生态环境知识资源中心(Arid): Detrital record of the denudation of volcanic islands under sub-tropical climate (Cape Verde)

Arid

DOI	10.1016/j.chemer.2019.02.001
	Detrital record of the denudation of volcanic islands under sub-tropical climate (Cape Verde)
	Dinis, Pedro A.; Cabral Pinto, Marina M. S.; Garzanti, Eduardo; Rocha, Fernando T.
通讯作者	Dinis, PA (corresponding author), MARE Marine & Environm Sci Ctr, Dept Earth Sci, P-3030790 Coimbra, Portugal.
来源期刊	GEOCHEMISTRY
ISSN	0009-2819
EISSN	1611-5864
出版年	2019
卷号	79 期号:2 页码:235-246
英文摘要	This research is focused on the composition of the sediments produced in volcanic islands when the climate does not favour weathering. The XRD mineralogy (bulk sample and fraction finer than 63 mu m), petrography and geochemistry of a set of bedload stream and beach samples collected in the old Maio and the young Fogo islands of Cape Verde archipelago are used to investigate the compositional transformations promoted by exogenous processes during island denudation. The main factor responsible for the variability in sediment composition is the incorporation of biogenic material derived from the evolving shelves; it largely exceeds the effects of the exhumation of different volcanic and basement units. Given the arid climate (and steep land surface in Fogo), only the most labile components of basaltic rocks, such as volcanic glass, are decomposed. The incipient weathering and sorting processes are responsible for the depletion of Al in bedload deposits. The same happens with other elements usually regarded as non-mobile (namely, Nb, Th, REE, etc.), while Mg is concentrated. Thus, weathering indices grounded on the premise that mobile elements are lost and non-mobile elements are enriched via weathering are useless in Cape Verde bedload sediments. With time, weathering is able to promote Na leaching and the formation of secondary minerals, which tend to retain non-mobile elements released in the earlier stages of alteration (e.g., LREE, Th, Y, Nb, Ta etc.). Sorting processes are responsible for the selective removal of less-dense grains, explaining local differences between beach and stream deposits. Beach placers are enriched in augitic clinopyroxene (occasionally also in olivine in the Fogo island), and Sc, Cr and Co. Niobium and Ta must be hosted in fine-grained particles that are easily windblown and their abundances in dusts may reveal Cape Verde as a source of airborne material crossing the Atlantic Ocean.
英文关键词	Geochemistry Mineralogy Weathering Sorting Cape Verde Volcanic islands
类型	Article
语种	英语
收录类别	SCI-E
WOS记录号	WOS:000494249000003
WOS关键词	FOGO ISLAND ; GEOCHEMICAL EVOLUTION ; DISSOLUTION RATES ; SANTIAGO ISLAND ; MAJOR ELEMENTS ; TRACE-ELEMENTS ; EROSION RATES ; CHEMISTRY ; BASALT ; FLUXES
WOS类目	Geochemistry & Geophysics
WOS研究方向	Geochemistry & Geophysics
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/369464
作者单位	[Dinis, Pedro A.] MARE Marine & Environm Sci Ctr, Dept Earth Sci, P-3030790 Coimbra, Portugal; [Cabral Pinto, Marina M. S.; Rocha, Fernando T.] Univ Aveiro, Dept Geosci, Geobiotec Res Ctr, P-3810193 Aveiro, Portugal; [Garzanti, Eduardo] Universitd Milano Bicocca, Dept Earth & Environm Sci, Lab Provenance Studies, I-20126 Milan, Italy
推荐引用方式 GB/T 7714	Dinis, Pedro A.,Cabral Pinto, Marina M. S.,Garzanti, Eduardo,et al. Detrital record of the denudation of volcanic islands under sub-tropical climate (Cape Verde)[J],2019,79(2):235-246.
APA	Dinis, Pedro A.,Cabral Pinto, Marina M. S.,Garzanti, Eduardo,&Rocha, Fernando T..(2019).Detrital record of the denudation of volcanic islands under sub-tropical climate (Cape Verde).GEOCHEMISTRY,79(2),235-246.
MLA	Dinis, Pedro A.,et al."Detrital record of the denudation of volcanic islands under sub-tropical climate (Cape Verde)".GEOCHEMISTRY 79.2(2019):235-246.