A lead isotope study of mineralization in the Saudi Arabian Shield

Stacey, J. S.; Doe, Bruce R.; Roberts, Ralph J.; Delevaux, Maryse H.; Gramlich, J. W.

doi:10.1007/bf01132003

Cited by 116 publications

(38 citation statements)

References 21 publications

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“…Graph also includes lead isotope data from the Arabian-Nubian Shield. Groups I and II are the compositional fields from Saudi Arabian galena (Stacey et al, 1980) ponding to a g I (238U/2°4pb) value of 8.3, are compatible with a mantle origin of the parental magma. After Zartman and Doe (1981), the upper mantle g value at that time is ~ 8.5, whereas the lower crust t-t value is ,,~ 6.3.…”

Section: Isotope Geochemistrymentioning

confidence: 90%

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Origin and regional significance of late Precambrian and early Palaeozoic granitoids in the Pan-African belt of Somalia

Lenoir¹,

Li�geois²,

K�ster³

et al. 1994

Geol Rundsch

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Granitoids within the Precambrian basement of north-eastern and southern Somalia are subdivided on the basis of geology, geochronology and petrology into three different assemblages. The post-kinematic assemblage in north-eastern Somalia (~ 630 Ma) comprises granodiorites and granites which belong to a medium-K calc-alkaline suite. Average initial Sr, Nd and Pb isotopic ratios [Sri = 0.7048, end = --1.8, 2°6pb/2°4pb(i) = 17.704 and 2°Tpb/2°4pb(i)= 15.611] indicate that these melts were derived from a mantle or juvenile crustal source with only slight involvement of pre-existing crust as a contaminant. Two different assemblages are found in southern Somalia. The older assemblage is composed of crustal anatectic, synkinematic, parautochthonous granites (~ 600 Ma) related to amphibolite facies retrogression of an intensively reworked pre-Pan-African crust [

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Section: Isotope Geochemistrymentioning

confidence: 90%

“…10. The common lead data are divided into two main groups according to the results of Stacey et al (1980). This two-fold common Pb distribution is based on a much larger data set than the three-fold representation of Harris et al (1990), which is based on a limited number of Nd isotopic data.…”

Section: Isotope Geochemistrymentioning

confidence: 99%

Origin and regional significance of late Precambrian and early Palaeozoic granitoids in the Pan-African belt of Somalia

Lenoir¹,

Li�geois²,

K�ster³

et al. 1994

Geol Rundsch

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“…Lead and neodymium isotope studies in the northern half of the Nubian Shield indicate that most of the contained Neoproterozoic rocks were Fig. 1 Location of VMS deposits or districts in thederived either from a Neoproterozoic mantle directly, or from Paleo-or Mesoproterozoic lower crustal rocks (e.g., Egypt and Western Sudan areas; Stacey et al 1982;Hargrove et al 2006). Few radiogenic isotope studies have been carried out in the southern half in Ethiopia and Kenya, but it appears that much of these areas is underlain by relatively juvenile crust that is distinct from the Neoarchean to Mesoproterozoic rocks of the Tanzania-Congo craton to the west (Johnson et al 2011;Stern et al 2012).…”

Section: Regional Geological Setting: the Neoproterozoic Nubian Shieldmentioning

confidence: 97%

Volcanogenic Massive Sulphide–Oxide Gold Deposits of the Nubian Shield in Northeast Africa

Barrie

Abdalla

Hamer³

2016

Mineral Deposits of North Africa

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The 0.85-0.55 Ga Arabian-Nubian Shield of northeast Africa comprises an assemblage of volcanic arc and sub-arc strata that are fertile for volcanogenic massive sulphide (VMS) and overlying oxide gold deposits. At least fifty VMS deposits are known in the Nubian Shield west of the Red Sea, many of which are clustered in districts. The most important districts, including Ariab in NE Sudan, Bisha in western Eritrea, and Asmara in eastern Eritrea, have seen significant exploration and development recently. The Ariab VMS-oxide gold district contains over 20 oxide gold deposits that have been mined since 1991 (>2 Moz Au recovered), with several having large Cu-Au (+ Zn + Ag) sulphide resources below the oxide gold resources, including Hadal Awatib East (67.8 Mt), Hassai South (42

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“…Since publication of one of the first Nd studies in the ANS [75], Nd whole-rock isotope analyses in conjunction with U-Pb single zircon dating have become routine in assessments of the ANS (e.g., [72]) and other orogenic belts (e.g., [76]). Other important approaches applied to the ANS since the 1980s are to use lead and strontium isotopes in whole-rock samples [77][78][79]. More recently, oxygen and hafnium isotopes have become increasingly used.…”

Section: Isotope Database and Ans Historymentioning

confidence: 99%

“…This finding suggested that the host rocks contain a large component of older continental lead in contrast to rocks elsewhere in the Arabian Shield that have lead of oceanic character. These older leads were initially referred to as Type II [77], but are now referred to as Type III [117]. Juvenile oceanic lead, concentrated in the western arc terranes of the ANS (Fig.…”

Section: Is There An Ans Margin In Central Arabia?mentioning

confidence: 99%

An Expanding Arabian-Nubian Shield Geochronologic and Isotopic Dataset: Defining Limits and Confirming the Tectonic Setting of a Neoproterozoic Accretionary Orogen

Johnson¹

2014

TOGEOJ

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Geologic investigations of the Arabian-Nubian Shield (ANS) are supported by a valuable, expanding dataset of geochronologic ages and isotopic analyses. U-Pb zircon SIMS, TIMS, and evaporation data provide robust temporal control on depositional, volcanic, and intrusive events. Nd, Sr, O and, increasingly, Hf isotopic studies provide insights into magma sources and constraints on crustal recycling. Apart from well-established exceptions where Paleoproterozoic and Archean rocks intercalated in the ANS underwent Neoproterozoic reworking, the data elegantly confirm the Neoproterozoic age and juvenile character of the bulk of the ANS. The geochronologic and isotopic data reveal that some ANS sedimentary, volcanic, and igneous rocks contain pre-Neoproterozoic material as xenocrysts and possible glaciogenic clasts, but give no evidence that the ANS is otherwise underlain by any extensive tracts of older crust. Together with structural mapping, the expanding dataset confirms ANS boundaries where long-inferred in the west and suggests the placement of hitherto uncertain boundaries elsewhere. The suggested boundaries imply that the ANS is of a somewhat smaller size than considered in published discussions, which in turn impacts assessment of Neoproterozoic crustal growth rate. The Arabian-Nubian Shield (ANS) is an accretionary orogen at the northern end (present-day coordinates) of the East African Orogen. It is one of the largest expanses of mantle-derived, juvenile Neoproterozoic crust on Earth, underlying an area of ~2.7 x 10 6 km 2 . Its western boundary is a contact with pre-Neoproterozoic crust belonging to the Saharan Metacraton and Congo-Tanzania Craton. Farther south, the ANS is in contact with the Congo-Tanzania Craton and Mozambique Belt. A southeastern ANS margin is recognized as a contact with pre-Neoproterozoic gneiss belonging to a crustal block referred to as Azania. An eastern ANS margin, long a topic of debate, is suspected beneath Phanerozoic cover in central Arabia, and a northwestern margin with late Mesoproterozoic crust is suspected in Sinai.

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A lead isotope study of mineralization in the Saudi Arabian Shield

Cited by 116 publications

References 21 publications

Origin and regional significance of late Precambrian and early Palaeozoic granitoids in the Pan-African belt of Somalia

Origin and regional significance of late Precambrian and early Palaeozoic granitoids in the Pan-African belt of Somalia

Volcanogenic Massive Sulphide–Oxide Gold Deposits of the Nubian Shield in Northeast Africa

An Expanding Arabian-Nubian Shield Geochronologic and Isotopic Dataset: Defining Limits and Confirming the Tectonic Setting of a Neoproterozoic Accretionary Orogen

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