In No. 50 kimberlite pipe of Fuxian County, Liaoning Province, an eclogite inclusion(nodule), which is extremely rare in kimberlites, was discovered and phlogopite exsolutionlamellae were found in garnets of the inclusion. Microscopic, TEM and energy spectral observa-tions and studies confirmed that these lamellae are phlogopite. They are colourless and acicularin section, generally 0.5-5μm in width and 10-100μm in length. Nevertheless, fine lamellae,0.05-0.1μm wide and 1-2μm long, are also well developed. Along [111] of the garnet, three setsof phlogopite lamellae show oriented arrangement approximately at angles of 60°-70°, indi-cating that these lamellae might be the product of exsolution from garnet as a result ofpressure-release when eclogite ascended from the relatively deep level to the relatively shallowlevel of the mantle. Tiny acicular exsolution minerals (or inclusions) are commonly found ingarnet and pyroxene in eclogite inclusions of kimberlites all over the world and it has been re-ported that the identified exsolution minerals include pyroxene and rutile. This is the first timethat phlogopite exsolution lamillae were found in eclogite inclusions in the world. 相似文献
The exsolution of volatile phases from silicate magmas controls physical and chemical magma properties and influences large-scale geologic phenomena and processes having major societal and economic implications including the release of climate-altering gases to the atmosphere, the explosivity of volcanic eruptions, hydrothermal alteration, and the generation of magmatic–hydrothermal mineralization. These volatile phases exsolve from a wide variety of magmas and cover a very broad spectrum of compositions.
The transition from the orthomagmatic to the hydrothermal stages has important bearing on these fundamentally important geologic phenomena, and this report summarizes the published results of a dozen scientific investigations on the magmatic–hydrothermal transition as applied to volcanic eruption and magmatic–hydrothermal mineralization. These studies involve a variety of analytical and experimental methodologies, and many focus on fluid and melt inclusions from mineralized magmatic systems. A primary goal of each study is to better understand the role of magmatic volatiles and the importance of the magmatic–hydrothermal transition on these geologic processes. 相似文献