نتایج جستجو برای: prograde metamorphism

تعداد نتایج: 2624  

2001
David A. Schecter Daniel H. E. Dubin

This paper examines two-dimensional vortex motion in a shear-flow with nonuniform vorticity. Typically, a vortex travels to an extremum in the background vorticity distribution. In general, the rate of this migration increases with the magnitude of the background vorticity gradient; however, a retrograde vortex, which rotates against the local shear, moves orders of magnitude faster than a prog...

2003
CARLES CANET PURA ALFONSO JOAN-CARLES MELGAREJO SUSANA JORGE

The Lower Llandoverian metasedimentary rocks of the Prades Mountains, southwestern Catalonia, Spain, consist of interstratified anorthite-rich beds, chert beds, phosphate beds, sulfide-rich black shale (with mainly pyrrhotite and minor chalcopyrite), massive sulfide lenses and calc-silicate beds. These metasedimentary rocks are anomalously enriched in V and Cr, and have disseminated minerals of...

2007
Axel Brandenburg

The outer surface layers of the sun show a clear deceleration at low latitudes. This is generally thought to be the result of a strong dominance of vertical turbulent motions associated with strong downdrafts. This strong negative radial shear should not only contribute to amplifying the toroidal field locally and to expelling magnetic helicity, but it may also be responsible for producing a st...

2002
John C. Ayers Stacie Dunkle Shan Gao Calvin F. Miller

The Dabie Shan Ultrahigh-Pressure Metamorphic (UHPM) Belt occupies the suture between the Yangtze and Sino-Korean blocks in east-central China. The timing of UHPM in the Dabie belt is controversial, and most recent data come from dating of zircons. Monazite has recently been recognized as useful for dating of multiple tectonic events due to its preservation of multiple growth zones, and monazit...

1997
H. Mo Helmy

Monazites from high-grade metapelitic paragneisses from the southern Eastern Desert of Egypt (Abu Swayel area) were analysed with the electron microprobe mainly in an attempt to broadly constrain the metamorphic ages of the rocks by means of chemical Th(U)-Pb dating. Two samples were investigated, one showed weak signs of a greenschist facies overprint, the other one did not. For each sample, w...

Journal: :Frontiers in Earth Science 2022

Late Paleozoic to early Mesozoic subduction complexes formed during the evolution of southwestern Gondwana and extensively crop out along Chilean continental margin. Recent findings in northern Patagonia (40°–43°S) revealed that accretionary processes were active since Devonian when enhanced lithosphere stretching forearc led formation Chaitenia island arc. The extension crust consecutively dev...

Journal: :Chemical Geology 2021

Molybdenum isotopes have emerged as novel tracers for high-temperature igneous and metamorphic processes. The debate remains to what extent different subducted slab lithologies, such oceanic crust marine sediments, contribute the Mo isotope signature of arc magmas and, hence, exert controls on terrestrial cycle. Here we investigate systematics from input output at Tongan subduction zone: Arc la...

Journal: :Geophysical Journal International 2005

2007
Axel Brandenburg

The outer surface layers of the sun show a clear deceleration at low latitudes. This is generally thought to be the result of a strong dominance of vertical turbulent motions associated with strong downdrafts. This strong negative radial shear should not only contribute to amplifying the toroidal field locally and to expelling magnetic helicity, but it may also be responsible for producing a st...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید