نتایج جستجو برای: granulite
تعداد نتایج: 412 فیلتر نتایج به سال:
We examine the timing of deformation and exhumation of the Nanga Parbat-Haramosh massif in the western syntaxis of the Himalaya. This study presents geochronologic and thermochronologic data obtained from basement, shear zone, and intrusive units within the massif to reveal the Cenozoic tectonic evolution of the massif and to document the extent of the Plio-Pleistocene tectonic activity. These ...
Sm-Nd ages of pegmatite dikes that crosscut gold-bearing structures in the southern Yilgarn Craton, Western Australia, provide minimum age constraints of 2640 6 11 Ma, 2628 6 10 Ma, and 2620 6 36 Ma for gold mineralization at the Westonia and Nevoria (Yellowdine Terrane) and Scotia (Norseman Terrane) gold deposits, respectively. Similarly, a post–gold mineralization dike at Westonia has a U-Pb ...
U–Pb zircon geochronology is hampered by problems acquiring meaningful geologic ages on zoned grains that retain isotope signatures from multiple growth or thermal events. We present a new method using laser ablation-multicollector-inductively coupled plasma-mass spectrometry to overcome complications asso ciated with intricately zoned zircon crystals through in situ sampling of zircon volumes...
High-grade gneisses (amphibolite–granulite facies) of the Namche Barwa and Gyala Peri massifs, in the eastern Himalayan syntaxis, have been unroofed from metamorphic depths in the late Tertiary–Recent. Rapid exhumation (2–5 mm year) has resulted in a pronounced shallow conductive thermal anomaly beneath the massifs and the intervening Tsangpo gorge. The position of the 300 !C isotherm has been ...
This paper first reports the counter-clockwise pressure-temperature (P–T) path for Lützow–Holm Complex in East Antarctica. The metamorphic textures of kyanite-bearing pelitic gneisses from Tenmondai Rock including earlier spinel and ilmenite inclusions, geothermobarometric data, pseudosection modeling indicate that pressure increases prior to peak conditions at around 9 ± 0.5 kbar 770–820 °C, f...
The Napier Complex in East Antarctica has a complex thermal history, including ultra-high-temperature (UHT) metamorphism. Geochronology, trace element, and isotope geochemistry of zircon, apatite, monazite three felsic gneisses collected from Harvey Nunatak were studied using sensitive high-resolution ion microprobe (SHRIMP) for the first time. Most zircons showed nebulous to fir-tree zoning, w...
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