Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.1007/BF02182952 |
Phosphate minerals in a lateritic crust from Venezuela | |
Tiessen, H; LoMonaco, S; Ramirez, A; Santos, MCD; Shang, C | |
通讯作者 | Tiessen, H |
来源期刊 | BIOGEOCHEMISTRY
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ISSN | 0168-2563 |
出版年 | 1996 |
卷号 | 34期号:1页码:1-17 |
英文摘要 | Ferruginous crusts and pisolites have chemical and mineralogical properties that differ from the surrounding soil due to Fe and Al enrichments which cause cementations that can harden irreversibly. In addition to, and possibly as a result of the Fe and Al accumulation, other ions, particularly phosphate are often also enriched by a factor of 2-20 relative to the surrounding soil. The P accumulated in ferruginous materials is normally bound to the Fe or Al in amorphous forms of low solubility. Distinct minerals have rarely been identified. We examined a section through a Venezuelan ferruginous crust, which contained portions with P contents >100 g kg(-1), chemically, mineralogically and micromorphologically with the aim to show some of the mechanisms that cause such extreme P accumulation and segregation in a landscape that is otherwise very nutrient poor. Except for the cementation, manifested as an in-filling of pores by Fe, the morphology of the ferruginous crusts reflected that of the original soil. At approx. 30 cm below the crust’s surface, goethite, strengite and leucophosphite (KFe2(PO4)(2)OH . 2H(2)O) were identified along a downward sequence of pores nearer the surface to pores at greater depth to the matrix of the lower crust. While the lower crust contained highly soluble P,Fe oxides from outer pore spaces showed high P sorption. The element and mineral distribution across thin sections suggested that incoming Fe had interacted with a soil matrix that was exceptionally rich in K and P to form highly soluble leucophosphite, followed by less soluble strengite and finally Fe oxides that essentially occluded the more soluble minerals found in the lower crust. Associated organic C dated at 18,700 y b.p., suggesting that the occlusion process occurred around the last glacial maximum, when the region became more arid. Although extreme in its extent, the process of separation and occlusion of minerals demonstrated here, may be useful for interpreting similar processes in soils and soil cementations that affect the biogeochemical turnover of elements. |
英文关键词 | carbon dating leucophosphite micromorphology paleo-climate pisolite P-sorption |
类型 | Article |
语种 | 英语 |
国家 | VENEZUELA ; BRAZIL |
收录类别 | SCI-E |
WOS记录号 | WOS:A1996VB07600001 |
WOS关键词 | PHOSPHORUS SORPTION ; FERRUGINOUS NODULES ; SOILS |
WOS类目 | Environmental Sciences ; Geosciences, Multidisciplinary |
WOS研究方向 | Environmental Sciences & Ecology ; Geology |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/132420 |
作者单位 | (1)CENT UNIV VENEZUELA,FAC CIENCIAS,INST CIENCIAS TIERRA,CARACAS,VENEZUELA;(2)UNIV FED PERNAMBUCO,DEPT AGRON,RECIFE,PE,BRAZIL |
推荐引用方式 GB/T 7714 | Tiessen, H,LoMonaco, S,Ramirez, A,et al. Phosphate minerals in a lateritic crust from Venezuela[J],1996,34(1):1-17. |
APA | Tiessen, H,LoMonaco, S,Ramirez, A,Santos, MCD,&Shang, C.(1996).Phosphate minerals in a lateritic crust from Venezuela.BIOGEOCHEMISTRY,34(1),1-17. |
MLA | Tiessen, H,et al."Phosphate minerals in a lateritic crust from Venezuela".BIOGEOCHEMISTRY 34.1(1996):1-17. |
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