Mantle sources and magma-continental crust interactions during early Red Sea-Gulf of Aden rifting in southern Yemen: Elemental and Sr, Nd, Pb isotope evidence

1993 ◽  
Vol 98 (B2) ◽  
pp. 1819-1835 ◽  
Author(s):  
Gilles Chazot ◽  
Herve Bertrand
Keyword(s):  
Continental Crust ◽  
Red Sea ◽  
Gulf Of Aden ◽  
Pb Isotope ◽  
Mantle Sources ◽  
Isotope Evidence

scholarly journals Trace-Element and Pb Isotope Evidence on Extracting Sulfides from Potassic Melts beneath Longmenshan and Molabushan Volcanoes, Wudalianchi, Northeast China

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 319 ◽  
Author(s):  
Sergei Rasskazov ◽  
Yi-Min Sun ◽  
Irina Chuvashova ◽  
Tatyana Yasnygina ◽  
Chen Yang ◽  
...  
Keyword(s):  
Trace Element ◽  
Volcanic Rocks ◽  
Volcanic Field ◽  
Lava Flows ◽  
Pb Isotope ◽  
Linear Pattern ◽  
Wide Range ◽  
Mantle Sources ◽  
Isotope Evidence ◽  
Isotope Study

In the Wudalianchi volcanic field, eruptions started with low-Mg potassic lava flows 2.5–2.0 Ma ago and later changed to both low- and moderate-Mg potassic compositions. Volcanic rocks from the Molabushan and Longmenshan volcanoes record an unusually wide range of Pb abundances (from 3.7 ppm to 21 ppm relative to predominant range of 10–15 ppm). To determine the cause of these, we performed a comparative trace-element and Pb isotope study of rocks from these volcanoes and older lava flows. On a uranogenic lead diagram, older low-Mg lavas from lithospheric mantle sources plot on a secondary isochron with a slope corresponding to an age of 1.88 Ga. This contrasts with moderate-Mg volcanic rocks from the Molabushan cone, interpreted to have been derived from a recent convective mantle source, which define a flat linear pattern. Low-Mg rocks from the Molabushan flow have lead isotopic compositions that indicate mixed Gelaqiu and Molabu sources. Relative to rocks from the Molabushan cone, moderate-Mg lavas and slags from the East Longmenshan volcano have modified compositions characterized by Pb, S, and Ni abundances, Ni/Co, Ni/MgO ratios as well as 206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb, Ce/Pb, Th/Pb, and U/Pb ratios. We infer that the older Wudalianchi magmas were likely derived from a Paleoproterozoic lithospheric fragment, related to the evolved primordial mantle, and that later magmas were generated in the convecting mantle. These were influenced by segregation of small amounts of sulfides.

Microearthquakes in the Tihamat-Asir region of Saudi Arabia

1980 ◽  
Vol 70 (6) ◽  
pp. 2291-2293
Author(s):  
H. M. Merghelani ◽  
S. K. Gallanthine
Keyword(s):  
Saudi Arabia ◽  
Continental Crust ◽  
Red Sea ◽  
Fault Plane ◽  
Seismic Refraction ◽  
Earthquake Hazard ◽  
Tectonic Activity ◽  
Fault Plane Solutions ◽  
High Level ◽  
Asir Region

abstract During the course of a seismic refraction investigation in Saudi Arabia, an unexpected high level of microearthquake activity was detected near the border of the Red Sea and near the transition from oceanic to continental crust. The data is not adequate to determine fault plane solutions nor to relate the earthquakes to specific structures, but the existence of microearthquakes at this location suggest that there is a significant level of tectonic activity at a point 200 km from an axial trough of the Red Sea. These data, combined with other recent geological observations, may be an important clue to the understanding of continental rifting. The data suggest the need for a more thorough investigation of the earthquake hazard along the shores of the Red Sea.

scholarly journals Sensitivity of Red Sea circulation to sea level and insolation forcing during the last interglacial

2011 ◽  
Vol 7 (2) ◽  
pp. 1195-1233 ◽  
Author(s):  
G. Trommer ◽  
M. Siccha ◽  
E. J. Rohling ◽  
K. Grant ◽  
M. T. J. van der Meer ◽  
...  
Keyword(s):  
Sea Level ◽  
Red Sea ◽  
Planktonic Foraminifera ◽  
Gulf Of Aden ◽  
Last Interglacial ◽  
The Holocene ◽  
Circulation Mode ◽  
Monsoon Strength ◽  
Mis 5E ◽  
Mis 5

Abstract. This study investigates the response of Red Sea circulation to sea level and insolation changes during termination II and across the last interglacial, in comparison with termination I and the Holocene. Sediment cores from the central and northern part of the Red Sea were investigated by micropaleontological and geochemical proxies. The recovery of the planktonic foraminiferal fauna following high salinities during MIS 6 took place at similar sea-level stand (~50 m below present day), and with a similar species succession, as during termination I. This indicates a consistent sensitivity of the basin oceanography and the plankton ecology to sea-level forcing. Based on planktonic foraminifera, we find that increased water exchange with the Gulf of Aden especially occurred during the sea-level highstand of interglacial MIS 5e. From MIS 6 to the peak of MIS 5e, northern Red Sea SST increased from 21 °C to 25 °C, with about 3 °C of this increase taking place during termination II. Changes in planktonic foraminiferal assemblages indicate that the development of the Red Sea oceanography during MIS 5 was strongly determined by insolation and monsoon strength. The SW Monsoon summer circulation mode was enhanced during the termination, causing low productivity in northern central Red Sea core KL9, marked by high abundance of G. sacculifer, which – as in the Holocene – followed summer insolation. Core KL11 records the northern tip of the intruding intermediate water layer from the Gulf of Aden and its planktonic foraminifera fauna shows evidence for elevated productivity during the sea-level highstand in the southern central Red Sea. By the time of MIS 5 sea-level regression, elevated organic biomarker BIT values suggest denudation of soil organic matter into the Red Sea and high abundances of G. glutinata, and high reconstructed chlorophyll-a values, indicate an intensified NE Monsoon winter circulation mode. Our results imply that the amplitude of insolation fluctuations, and the resulting monsoon strength, strongly influence the Red Sea oceanography during sea-level highstands by regulating the intensity of water exchange with the Gulf of Aden. These processes are responsible for the observation that MIS 5e/d is characterized by higher primary productivity than the Holocene.

Propagation of Gulf of Aden Intermediate Water (GAIW) in the Red Sea during autumn and its importance to biological production

2016 ◽  
Vol 154 ◽  
pp. 243-251 ◽  
Author(s):  
Mohideen Wafar ◽  
Mohamed Ashraf ◽  
K.P. Manikandan ◽  
Mohammad Ali Qurban ◽  
Yasser Kattan
Keyword(s):  
Red Sea ◽  
Intermediate Water ◽  
Gulf Of Aden ◽  
Biological Production

scholarly journals Elemental and Sr–Nd–Pb isotope geochemistry of the Cenozoic basalts in Southeast China: Insights into their mantle sources and melting processes

Lithos ◽  
2017 ◽  
Vol 272-273 ◽  
pp. 16-30 ◽  
Author(s):  
Pu Sun ◽  
Yaoling Niu ◽  
Pengyuan Guo ◽  
Lei Ye ◽  
Jinju Liu ◽  
...  
Keyword(s):  
Isotope Geochemistry ◽  
Pb Isotope ◽  
Southeast China ◽  
Mantle Sources
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