Perim Island, a volcanic remnant in the southern entrance to the Red Sea

1990 ◽  
Vol 127 (4) ◽  
pp. 309-318 ◽  
Author(s):  
D. I. J. Mallick ◽  
I. G. Gass ◽  
K. G. Cox ◽  
B. V. W. De Vries ◽  
A. G. Tindle
Keyword(s):  
Trace Element ◽  
Red Sea ◽  
Fractional Crystallization ◽  
Late Miocene ◽  
Gulf Of Aden ◽  
Sea Floor ◽  
Element Abundances ◽  
Major Oxide ◽  
Propagating Rift ◽  
Sea Floor Spreading

AbstractPerim Island is an eroded fragment of the southwest flank of a late Miocene (10.5 ± 1.0 Ma) volcano whose centre lay on the southwesternmost tip of Arabia. The volcano is the westernmost of the E–W line of six central vent volcanoes (the Aden Line) that extends 200 km along the south coast of Arabia from Perim to Aden. Major oxide and trace element abundances are given for 35 Perim specimens and these show that the volcano has within-plate trace element characteristics and consists of a petrographically and geochemically simple suite of alumina-poor olivine basalts, andesites, and transitional andesite–trachyandesites. Six specimens, however, are markedly enriched in Al2O3 and CaO, and contain abundant (20–30 mode %) highly calcic (An77–83) plagioclase phenocrysts. Geochemical modelling suggests that the main Perim volcanic sequence was produced by the fractional crystallization (o1 + cpx + Ti-mt + plag) of a silica saturated (SiO2 c. 45%) basic melt. The high A1, high Ca, magmas appear to be mixing products of plagioclase-enriched basic magmas with more evolved melts. Perim is the oldest volcano of the Aden line, which becomes increasingly younger and alkalic eastward. It is suggested that the volcanism is related to an eastwards-propagating rift produced before the most recent stage of sea-floor spreading in the Gulf of Aden (4.5 Ma–present).

A discussion on the structure and evolution of the Red Sea and the nature of the Red Sea, Gulf of Aden and Ethiopia rift junction - Introductory remarks

1970 ◽  
Vol 267 (1181) ◽  
pp. 5-7 ◽  
Keyword(s):  
Red Sea ◽  
World Ocean ◽  
The Other ◽  
Rift System ◽  
Gulf Of Aden ◽  
Sea Floor ◽  
The Earth ◽  
The World ◽  
The Many ◽  
Sea Floor Spreading

The Red Sea Discussion Meeting originated in the desire of the other organizers to bring together as many as possible of the earth scientists who have been working recently in that area to examine the latest evidence and ideas on its structure and origin, to see how they accord with modern continental and sea-floor spreading concepts. The Red Sea, Gulf of Aden and Afar crustal depressions, now known to be continuous with the extension of the world ocean rift system, have been claimed as a manifestation of crustal separation, but some Earth scientists still consider that the evidence can be explained by less drastic crustal rifting. Definite solutions to the many outstanding problems were not expected but discussions would clearly assist further researches.

A discussion on the structure and evolution of the Red Sea and the nature of the Red Sea, Gulf of Aden and Ethiopia rift junction - The deep structure of the Red Sea

1970 ◽  
Vol 267 (1181) ◽  
pp. 181-189 ◽  
Keyword(s):  
Red Sea ◽  
Seismic Velocity ◽  
Deep Structure ◽  
Gravity Data ◽  
Seismic Refraction ◽  
Seismic Survey ◽  
Gulf Of Aden ◽  
Sea Floor ◽  
Central Trough ◽  
Sea Floor Spreading

The results of an intensive seismic survey in the Red Sea are presented. Analysis of twenty seismic refraction lines leaves no doubt that much more than just the central trough of the Red Sea is underlain by material with a seismic velocity which is characteristic of oceans. In addition, up to 5 km of what we interpret as evaporites were regularly found. The suggestion that the Red Sea crust could be oceanic in character over the major part of its width is examined in conjunction with magnetic and gravity data. We conclude that there is no evidence against sea floor spreading on a substantial scale in the Miocene. The implications of this in terms of neighbouring features is briefly discussed.

scholarly journals Mineralogy, Geochemistry, and Origin of Buyukmahal Manganese Mineralization in the Artova Ophiolitic Complex, Yozgat, Turkey

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Nursel Öksüz ◽  
Neslihan Okuyucu
Keyword(s):  
Trace Element ◽  
Spreading Center ◽  
Geochemical Data ◽  
Manganese Ore ◽  
Ophiolite Complex ◽  
Sea Floor ◽  
Manganese Mineralization ◽  
Major Oxide ◽  
Sea Floor Spreading ◽  
Ophiolitic Complex

The Artova ophiolite complex (AOC) is exposed along the northwestern and eastern margins of Yozgat area in Turkey. The Mn-deposit in the Buyukmahal area is part of this ophiolite complex. The deposit is in banded and lenticular forms and hosted by a radiolarite unit overlying the volcanics. Pyrolusite and magnetite are the main minerals of the manganese ore in the Buyukmahal (Yozgat) area. The gang minerals in the deposit are composed only of quartz and calcite. In this study, mineralogy, major oxide, trace element and REE contents of Buyukmahal manganese mineralization are evaluated. The geochemical data indicate that Buyukmahal mineralization does not originate from a pure hydrothermal or pure hydrogenous source but from a system consisting of both sources. It is also asserted that the mineralization was first developed on a sea floor spreading center within the Alpine Ophiolite System and then obducted as part of the AOC.

Two Stage Red Sea Floor Spreading

Nature ◽  
1974 ◽  
Vol 247 (5435) ◽  
pp. 7-11 ◽  
Author(s):  
R. W. GIRDLER ◽  
P. STYLES
Keyword(s):  
Red Sea ◽  
Two Stage ◽  
Sea Floor ◽  
Sea Floor Spreading

Open-system evolution versus source control in basaltic magmas: Matachewan–Hearst dike swarm, Superior Province, Canada

1990 ◽  
Vol 27 (6) ◽  
pp. 767-783 ◽  
Author(s):  
Dennis O. Nelson ◽  
Donald A. Morrison ◽  
William C. Phinney
Keyword(s):  
Trace Element ◽  
Fractional Crystallization ◽  
Incompatible Trace Element ◽  
Source Control ◽  
Superior Province ◽  
Crustal Rock ◽  
Dike Swarm ◽  
Element Abundances ◽  
Field Evidence ◽  
Element Enrichment

The 2.45 Ga Matachewan–Hearst dike swarm was emplaced over 250 000 km2 in diverse granitoid–greenstone and metasedimentary terranes of the Superior Province of Canada. The Fe-rich tholeiitic dikes host large, uniform plagioclase megacrysts and display significant trace-element variations, e.g., (La/Sm)N = 0.62–2.23, not correlated to terrane lithologies.Fractional crystallization alone cannot produce these variations or simultaneously account for both major- and trace-element abundances. Combined periodic replenishment–fractional crystallization (RFC) in shallow magma chambers is consistent with major- and trace-element concentrations and with field evidence for periodic magma injection within the dikes. RFC cannot, however, produce the observed variation in incompatible-trace-element ratios, e.g., (La/Sm)N. Models invoking mixed mantle sources are unsuccessful at reproducing trace-element trends. Combined assimilation–fractional crystallization (AFC) models, assuming depleted parental magmas and using crustal rock data from xenoliths and from the Kapuskasing Structural Zone, can accommodate the trace-element variations, including the light-rare-earth-element enrichment and the observed relative depletions of the high-field-strength elements. The AFC process apparently took place in the lower crustal regions from where evolved magmas were periodically transported to shallow chambers dominated by RFC.

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