نتایج جستجو برای: element deposits
تعداد نتایج: 231488 فیلتر نتایج به سال:
Rare earth elements (REE) are either housed in exotic REE minerals that sporadically populate the host rock or they occur as ionic substitutions in the crystal structure of existing rock-forming minerals. The genesis of REEs in carbonatite rocks can result in intricate mineralogical textures between REE minerals, host rock minerals, and minerals formed by later processes. Upfront mineralogical ...
The Segura mining field, the easternmost segment of Góis–Panasqueira–Segura tin–tungsten metallogenic belt (north–central Portugal), includes Sn-W quartz veins and Li-Sn aplite-pegmatites, which are believed to be genetically related Variscan Granites. Sediment geochemistry indicates granite-related Ti-enrichments, locally disturbed by mineralization, suggesting magmatic metamorphic/metasomatic...
Bentonite deposits of economic interest are widespread in Tashtab Mountains (Khur), east of Isfahan province, Iran. Several bentonite deposits have been developed in this area as a result of Eocene volcanic alteration. These deposits are classified as Khur bentonite horizon. XRD analyses reveal that alteration products consist of Na-montmorillonite, kaolinite, quartz, calcite, and crystobalite....
Supraglacial deposits are known for their influence on glacier ablation. The magnitude of this influence depends on the thickness and the type of the deposited material. The effects of thin layers of atmospheric black carbon and of thick moraine debris have been intensively studied. Studies related to regional-scale deposits of volcanic tephra with thicknesses varying between millimetres and me...
The shape of deposits obtained from drying drops containing colloidal particles matters for technologies such as inkjet printing, microelectronics, and bioassay manufacturing. In this work, the formation of deposits during the drying of nanoliter drops containing colloidal particles is investigated experimentally with microscopy and profilometry, and theoretically with an in-house finite-elemen...
Origin of Lunar Basalts: A Geophysical Interpretation J. Arkani-Hamed Lunar Pyroclastic Soils of the Apollo 17 Double Drive Tube 74001/2 A. Basu, D. S. McKay, and S. J. Wentworth Lunar Explosive Volcanism: The Remote Sensing Perspective C. R. Coombs and B. R. Hawke The Optimal Lunar Resource: Ilmenite-rich Regional Pyroclastic Deposits C. R. Coombs, B. R. Hawke, and B. Clark Pyroclastic Volcani...
Tephra is a product of large and explosive volcanic events and can travel thousands of kilometers before deposition. Consequently, tephra deposits are common in terrestrial, lacustrine, marine, and glacial environments. Because tephra deposition is a geologically synchronous event, tephras constitute important isochrones in the Quaternary sequence, not only in Japan but also throughout the nort...
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