The Erongo subvolcanic center in Namibia is the largest composite, bimodal complex in the Mesozoic Etendeka igneous province of Namibia. This study of 40Ar/39Ar and high spatial resolution U^Pb zircon dating demonstrates that emplacement of the various igneous units at Erongo took place within a time span equivalent to or shorter than geochronologically resolvable age differences (ca. 2 Ma), an...

For the past 40 years, the Moon has been described as nearly devoid of indigenous water; however, evidence for water both on the lunar surface and within the lunar interior have recently emerged, calling into question this long-standing lunar dogma. In the present study, hydroxyl (as well as fluoride and chloride) was analyzed by secondary ion mass spectrometry in apatite [Ca(5)(PO(4))(3)(F,Cl,...

The hypothesis that thermal plumes contribute to the Cenozoic magmatism in East Africa is now widely accepted. The controversy lies on how many plumes exist and where they may be located. In this study we show numerical experiments of mantle convection models for a number of thermal plume models and discuss the implications for the melt generation in East Africa. We investigate how the plume(s)...

Purpose. Studying the geological features of large industrial Atasu type ore objects. Methodology. Critical analysis literature and stock materials, comparative factors characteristic stratiform ores, stages peculiarities formation depending on processes volcanism, results isotope dating rocks. Findings. Participation volcanism (magmatism) in forming deposits ferromanganese barite-polymetallic ...

introduction the study area is located in central part of the khaf- kashmar-bardeskan belt which is volcano-plutonic belt at the north of the dorouneh fault in the north of lut block. the north of the lut block is affected by tectonic rotation and subduction processes which occur in the east of iran (tirrul et al., 1983). the magmatism of lut block begins in jurassic and continues in tertiary (...

a r t i c l e i n f o Keywords: East Pacific Rise mid-ocean ridge oceanic crust off-axis magmatism waveform modeling Formation of oceanic crust along the East Pacific Rise is thought to be complete within a few kilometers of the rise axis. Here, however, we present evidence for magmatism 20 km from the spreading center in 300-ka-old crust. Seismic data reveal an intrusive complex ~ 2 km beneath...

Slab breakoff is the buoyancy-driven detachment of subducted oceanic lithosphere from the light continental lithosphere that follows it during continental collision. In a recent paper Davies and von Blanckenburg [1994] have assessed the physical conditions leading to breakoff by quantitative thermomechanical modeling and have predicted various consequences in the evolution of mountain belts. Br...

Abstract Felsic tuff as a direct fallout deposit is known from one small area in the Kyrenia Range, north Cyprus, within deep-sea terrigenous turbidites. Nearby tuffaceous siltstones contain compositionally similar felsic volcanic rocks ( c. 5–10%), mixed with material. Sedimentary evidence indicates that was variable reworked locally, whereas are interpreted turbidites material derived Anatoli...