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在里希尔岛上一个第四纪破火山口下,有—套厚的碱性侵入体和火山岩地层,该地层成为目前仍在活动的地表热液体系的主岩,浅成热液金矿化即与之有关。从钾化带、泥化带至前进泥化带的蚀变层序中,(La/Lu)_(cn)和(La/Sm)_(cn)球粒陨石标准化比值逐渐增加;(Tb/Lu)_(cn)比值仅在泥化带和前进泥化带中有明显增大。表生氧化蚀变岩和酸性硫酸盐溶液沉积物比下伏的浅部蚀变带具有明显低的(La/Lu)_(cn)和(Tb/Lu)_(cn)比值。从浅部蚀变带到表生蚀变带,REE、LREE和HREE分馏趋势的变化,反映了从深部的岩浆热液、中性氯化物流体状态转变到蚀变剖面上部的酸性硫酸盐大气水的状态。富LREE,Eu的岩浆流体的沸腾,至少发生在750m的深处。可以认为大约在300-350m上方,由于气相和液相流率明显不同以及溶液的化学变化,使得LREE和Eu结合进入硬石膏——方解石脉中,而LREE和HREE沉积在钾化带上部的围岩中。气相冷凝后进入大气水并产生低温酸性流体,以至在泥化带和前进泥化带中沉积了大量的LREE。由于流体的量很大,并呈酸性流体环境且溶液中有丰富的硫酸盐络合物,因此,这时还伴有HREE的活动。HREE或是从热液体系中失去,或是沉积在氧化带和酸性硫酸盐溶液的沉积物中。
Under a Quaternary caldera on the island of Rishir, there is a set of thick alkaline intrusions and volcanic formations that have become the main rock of the currently active surface hydrothermal system, the epithermal gold mine That is related to it. The normalized ratios of (La / Lu) _ (cn) and (La / Sm) _ (cn) chondrites increase gradually from the alteration sequence of potassic zone and mud zone to advancing mud zone. (Tb / Lu) _ (cn) ratio is only significantly increased in the mud zone and advancing mud zone. The epiphytic alteration rocks and acidic sulfate solution sediments have significantly lower (La / Lu) _ (cn) and (Tb / Lu) _ (cn) ratios than the underlying shallow alteration zones. The trend of REE, LREE and HREE fractionation trends from shallow to epicontinental alteration reflects the transition from the magmatic hydrothermal and neutral chloride fluids in the deep to the acidic sulphate and atmospheric water in the upper part of the alteration profile status. The boiling of magmatic fluids enriched in LREE and Eu occurs at least at a depth of 750 m. It can be considered that above about 300-350 m, LREE and Eu are incorporated into the anhydrite-calcite veins due to the distinctly different gas and liquid flow rates and chemical changes of the solution, while LREE and HREE are deposited on the upper part of the potassic zone Rock. The gas phase condenses into atmospheric water and produces a low temperature acidic fluid that deposits large amounts of LREE in the mud zone and advancing mud zone. Due to the large amount of fluid and acidic fluid environment and the solution is rich in sulfate complexes, therefore, now also associated with HREE activity. HREE is either lost from the hydrothermal system or deposited in the sediment of the oxidation zone and acidic sulfate solution.