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DOI | 10.1007/BF01083228 |
PRECAMBRIAN BASEMENT AROUND WADI-HALFA, SUDAN - A NEW PERSPECTIVE ON THE EVOLUTION OF THE EAST SAHARAN CRATON | |
STERN, RJ; KRONER, A; BENDER, R; REISCHMANN, T; DAWOUD, AS | |
通讯作者 | STERN, RJ |
来源期刊 | GEOLOGISCHE RUNDSCHAU
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ISSN | 0016-7835 |
出版年 | 1994 |
卷号 | 83期号:3页码:564-577 |
英文摘要 | This paper provides new geochemical and isotopic data on the evolution of the western foreland to the Nubian shield of north-east Africa. There is abundant evidence for early to middle Proterozoic crust west of the River Nile, but this was severely affected by the Pan-African (almost-equal-to 500-900 Ma) orogenic cycle. The results are reported of Rb-Sr whole rock and zircon evaporation geochronological studies and whole rock Sm-Nd and feldspar Pb isotopic analyses for four rock units around Wadi Halfa in northern-most Sudan. These results indicate the presence of heterogeneous pre-Pan-African crustal components, preserved in mylonitic gneisses and in conglomerates that unconformably overlie the gneisses. Several episodes of crust formation, inferred from zircon ages, are preserved in the gneisses: 2.6, 2.4, 2.0, 1.7, 1.2 and 0.72 Ga. Nd model ages for the same units are invariably older than the zircon ages, yet still record a predominantly late Archaean and Palaeoproterozoic history, with depleted mantle model ages between 1.3 and 2.8 Ga. The earliest recorded Pan-African magmatic event is about 720 Ma and dates the beginning of collisional deformation. A younger Pan-African volcanic sequence (almost-equal-to 650 Ma) has isotopic compositions of Sr and Nd compatible with derivation from late Proterozoic asthenospheric mantle. A almost-equal-to 530 Ma anorogenic ’A-type’ granite also has isotopic compositions suggesting derivation from a primitive source. The inferred tectonic evolution began with rifting to form an oceanic re-entrant. This was followed by subduction leading to collision at about 700 Ma, accompanied by post-orogenic rifting at about 650 Ma. |
英文关键词 | PRECAMBRIAN GEOCHRONOLOGY GEOCHEMISTRY CRUSTAL EVOLUTION AFRICA |
类型 | Article |
语种 | 英语 |
国家 | GERMANY ; SUDAN |
收录类别 | SCI-E |
WOS记录号 | WOS:A1994PT47600009 |
WOS关键词 | CRUSTAL EVOLUTION ; ISOTOPIC EVIDENCE ; NUBIAN SHIELD ; NORTHEASTERN AFRICA ; PROTEROZOIC CRUST ; ARABIAN SHIELD ; GRANITIC-ROCKS ; EGYPT ; DESERT ; GEOCHRONOLOGY |
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/2XILL650/130056 |
作者单位 | (1)JOHANNES GUTENBERG UNIV,INST GEOWISSENSCH,D-55099 MAINZ,GERMANY;(2)UNIV KHARTOUM,DEPT GEOL,KHARTOUM,SUDAN |
推荐引用方式 GB/T 7714 | STERN, RJ,KRONER, A,BENDER, R,et al. PRECAMBRIAN BASEMENT AROUND WADI-HALFA, SUDAN - A NEW PERSPECTIVE ON THE EVOLUTION OF THE EAST SAHARAN CRATON[J],1994,83(3):564-577. |
APA | STERN, RJ,KRONER, A,BENDER, R,REISCHMANN, T,&DAWOUD, AS.(1994).PRECAMBRIAN BASEMENT AROUND WADI-HALFA, SUDAN - A NEW PERSPECTIVE ON THE EVOLUTION OF THE EAST SAHARAN CRATON.GEOLOGISCHE RUNDSCHAU,83(3),564-577. |
MLA | STERN, RJ,et al."PRECAMBRIAN BASEMENT AROUND WADI-HALFA, SUDAN - A NEW PERSPECTIVE ON THE EVOLUTION OF THE EAST SAHARAN CRATON".GEOLOGISCHE RUNDSCHAU 83.3(1994):564-577. |
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