Chemical composition and tectonic setting of the Dokhan Volcanic Formation, Eastern Desert, Egypt

Ressetar, R.; Monrad, J.R.

doi:10.1016/0899-5362(83)90002-7

Cited by 50 publications

(31 citation statements)

References 14 publications

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“…2 Map showing the distribution of the Dokhan volcanics in North Eastern Desert and the location of the study area (modified from the Geological map of Egypt 1981). The location of the previously studied Dokhan volcanics are indicated by numbers as follows: 1 G. Nuqara (Stern and Gottfried 1986); 2 Wassif area (Heikal et al 1980); 3 Wadi Queih (El Gaby et al 1989); 4 Fatira area (Ressetar and Monard 1983); 5 G. Dokhan (Stern and Gottfried 1986); 6 G. Abu Had (Ragab 1987); 7 El Kharaza (Abdel Rahman 1996) Takla et al 1997) have shown that the volcanic rocks in this area comprise both island arc metavolcanics and Dokhan volcanics. The island-arc metavolcanics are the oldest rock units that have been intruded by granitic rocks ranging in composition from tonalite to granodiorite (older granitoids); the latter were invaded by the Dokhan volcanics which in turn were intruded by leucogranites (younger granitoids) and later dykes.…”

Section: Field Relations and Petrographymentioning

confidence: 96%

“…3). Previous studies of the Wadi Fatira area (e.g., Sabet et al 1972;Ressetar and Monard 1983;Abu El-Leil and El Gammal 1991;Abu El-Leil et al 1991; Hashad 1980;Greenberg (1981); Stern and Hedge (1985); Beyth et al (1994); Moghazi et al (1998Moghazi et al ( , 1999 Hammamat group Sandstone, conglomerate, greywacke and volcaniclastics 600-585 Willis et al (1988) Dokhan volcanics Andesite and rhyolite flows and pyroclastics 620-550 Stern and Hedge (1985); Stern and Gotfried (1986);Segev (1987); Abdel Rahman and Doig (1987) Older granitoids Quartz diorite, tonalite, granodiorite, and tronhjemite 750-610 Hashad (1980); Dixon (1981); Stern and Hedge (1985); Moghazi (1999) Island arc assemblage Basalt, andesite, and rhyolite flows (YMV) and gabbro-diorite complexes associated with volcanogenic metasediments 820-620 Stern (1981); Stern and Hedge (1985); Kröner et al (1990) Ophiolitic group Serpentinites and talc carbonates, melange, deformed gabbro, and pillow lava (OMV) 810-730 Kröner et al (1992) Fig . 2 Map showing the distribution of the Dokhan volcanics in North Eastern Desert and the location of the study area (modified from the Geological map of Egypt 1981).…”

Section: Field Relations and Petrographymentioning

confidence: 99%

“…2) is an exposure of Neoproterozoic basement in Eastern Egypt where various volcanic and plutonic rocks are exposed. This area was selected for the present study because it is very accessible and because previous geochemical studies suggest that the Dokhan volcanics in this area Stern 1981) represent either a transitional stage between active subduction and extensional tectonics (Ressetar and Monard 1983) or active continental margin volcanics (Takla et al 1997). This study presents new data on lithostratigraphic and whole-rock chemical composition of the Dokhan volcanics in this area aiming at discussing the problem of tectonic environment in which they were erupted.…”

Section: Introductionmentioning

confidence: 99%

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Geochemistry, petrogenesis and tectonic setting of late Neoproterozoic Dokhan-type volcanic rocks in the Fatira area, eastern Egypt

Mohamed¹,

Moghazi²,

Hassanen³

2000

International Journal of Earth Sciences

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The Neoproterozoic Dokhan volcanics of the Fatira area in eastern Egypt comprise two main rock suites: (a) an intermediate volcanic suite, consisting of basaltic andesite, andesite, dacite, and their associated pyroclastic rocks; and (b) a felsic volcanic suite composed of rhyolite and rhyolitic tuffs. The two suites display well-defined major and trace element trends and a continuum in composition with wide ranges in SiO 2 (54-76%), CaO (8.19-0.14%), MgO (6.96-0.04%), Sr (983-7 ppm), Zr (328-95 ppm), Cr (297-1 ppm), and Ni (72-1 ppm). They are enriched in LILEs (Rb, Ba, K, Th, Ce) relative to high field strength elements (Nb, Zr, P, Ti) and show strong affinity to calc-alkaline subduction-related rocks. However, their undeformed character, their emplacement temporally and spatially with post-orogenic A-type granite, and their high Zr/Y values suggest that their emplacement follow the cessation of subduction in eastern Egypt in an extensionalrelated within-plate setting. Major and trace element variations in the intermediate volcanics are consistent with their formation via partial melting of an enriched subcontinental lithospheric mantle source followed by a limited low-pressure fractional crystallization of olivine and pyroxene before emplacement. The LILE enrichment relative to HFSE is attributed to the inheritance of a subduction component from mantle material which constituted the mantle wedge during previous subduction events in eastern Egypt. The evolution of the whole volcanic spectrum was governed mainly by crystal/melt fractionation of amphibole, plagioclase, titanomagnetite, and apatite in the intermediate varieties and plagioclase, amphibole, biotite, Fe-Ti oxides, apatite, and zircon in the felsic varieties. At each stage of evolution, crystal fractionation was accompanied by variable degrees of crustal contamination.

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Section: Field Relations and Petrographymentioning

confidence: 96%

Section: Field Relations and Petrographymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Geochemistry, petrogenesis and tectonic setting of late Neoproterozoic Dokhan-type volcanic rocks in the Fatira area, eastern Egypt

Mohamed¹,

Moghazi²,

Hassanen³

2000

International Journal of Earth Sciences

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“…The bedrock sources for these artefacts are likely Late Cretaceous to Tertiary (Early Miocene) because metamorphism has affected older Egyptian volcanic rocks (Ressetar and Monrad, 1983). Thus the basalts discussed here are all younger than 90 My and represent all known, unaltered flow, or flow units, in Egypt, regardless of whether they contain an identified ancient quarry (Figure 1).…”

Section: Basalt Samplesmentioning

confidence: 96%

The major‐ and trace‐element whole‐rock fingerprints of Egyptian basalts and the provenance of Egyptian artefacts

2001

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Discrimination diagrams have been developed that source Egyptian basaltic artefacts using whole-rock major element geochemistry. versus Zr/Y) to determine the bedrock sources. These diagrams have been applied to seven First Dynasty basalt vessels (Abydos), two Fourth Dynasty basalt paving stones (Khufu's funerary temple, Giza), and two Fifth Dynasty paving stones (Sahure's complex, Abu Sir). They show that the bedrock source for all the artefacts was the Haddadin flow in northern Egypt. Multidimensional scaling and cluster analysis applied to the whole-rock data (major elements and trace elements together) and previously published mineral fingerprinting studies confirm these results. Comparing mineral versus whole-rock fingerprinting techniques, a major advantage of the former is the small sample size required (0.001 g compared to Ն 0.1 g). Analytical costs are similar for both methods assuming that a comparison (bedrock) database can be assembled from the literature. For most archaeological problems, a whole-rock bedrock database is more likely to exist than a mineral database, and whole-rock analyses on artefacts will generally be easier to obtain than mineral analyses. Whole-rock fingerprinting may be more sensitive than mineral-based fingerprinting. Thus, if sample quantity is not an issue, whole-rock analysis may have a slight cost, convenience, and technical advantage over mineral-based methods. Our results also emphasize that the Egyptians cherished their Haddadin basalt flow and used it extensively and exclusively for manufacturing basalt vessels and paving stones for at least 600 years (ϳ3150 B.C. to 2500 B.C., approximate ages of the vessels and Abu Sir paving stones, respectively). ᭧

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“…Geologic map for Gabal Hadarba area formed (1) in a subduction environment (Hassan and Hashad, 1990;El Gaby et al, 1990), (2) in association with extension after crustal thickening (Stern et al, 1984(Stern et al, , 1988Stern, 1994;Fritz et al, 1996),(3) during transition between subduction and extension (Ressetar and Monard, 1983;Mohamed et al, 2000).…”

Section: Figure1 Location Map and Google Image For Hadarba Area ( )mentioning

confidence: 99%

Geology, Geochemistry and Radioactivity of Granitic and Volcanic Rocks at Hadarba Area, South Eastern Desert, Egypt

Shahin¹,

Masoud²,

Bayoumi³

2016

Int. Res. J. Geol. Min

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The present work deals with geology, geochemistry, radioactivity and tectonic environment of the granitic and volcanic rocks at Hadarba area, South Eastern Desert of Egypt. The granitic rocks comprise tonalite-granodiorite and monzogranite, while volcanic rocks include rhyolite, rhyodacite anddacite. These rocks are characterized by high concentrations of SiO2, Na2O, Fe2O3, K2O, Zr, Nb and Y but low in MgO, CaO, Cr, Ni, Sr, Ga and V. Field studies indicate that Dokhan volcanics extrude both tonalite-granodiorite and monzogranite with sharp contact forming a thick successive sequence of laminated acid lava flows, crystal lapilli tuffs and agglomerates. They range in composition from rhyolite, rhyodacite to dacite. Shear zone comprise lines-arranged intrusions trending NE-SW direction were recorded north Gabal Hadarba and extends for about 2.3 km in length with a width reaches up to 10 meter. These lines-arranged intrusions include quartz vein, microgranite and basic dykes. These shear zones cut through monzogranite. Petrochemical studies and tectonic discrimination diagrams for the monzogranite reveal that it is classified as granite developed in the within-plate tectonic environment, while Dokhan volcanics are classified as rhyolite and dacite developed in the immature island arcs and active continental margin environments.Field radiometric measurements of these granitic and volcanic rocks reveal low uranium and thorium contents. Uranium contents range from 1.2 to 2.7 ppm in the tonalite-granodiorite, from 1.1 to 8.5 ppm in the monzogranite, from 1.3 to 9.3 ppm in the Dokhan volcanic and from 1.4 ppm to 15.4 ppm in the felsite dyke.

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Chemical composition and tectonic setting of the Dokhan Volcanic Formation, Eastern Desert, Egypt

Cited by 50 publications

References 14 publications

Geochemistry, petrogenesis and tectonic setting of late Neoproterozoic Dokhan-type volcanic rocks in the Fatira area, eastern Egypt

Geochemistry, petrogenesis and tectonic setting of late Neoproterozoic Dokhan-type volcanic rocks in the Fatira area, eastern Egypt

The major‐ and trace‐element whole‐rock fingerprints of Egyptian basalts and the provenance of Egyptian artefacts

Geology, Geochemistry and Radioactivity of Granitic and Volcanic Rocks at Hadarba Area, South Eastern Desert, Egypt

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