Mineralogical and geochemical characteristics of scheelite-bearing skarns,and genetic relations between skarn mineralization and petrogenesis of the associated granitoid pluton at Sargipali,Sundergarh District,Eastern India

Skarn rocks occur at the contact between calcite-bearing dolomitic marbles and granitoids (massive varieties with pegmatites) in close spatial association with the mica schist-hosted Proterozoic Pb–Cu–Ag sulfide deposits at Sargipali, Sundergarh District, Eastern India. The exoskarn (pyroxene–garnet) of variable width (1 to 30 m) occurs in marble proximal to the granitic intrusion, and endoskarn (pyroxene–epidote) is variably developed (< 1 to 10 m). Molybdenum-free scheelite with minor pyrrhotite (0.2%) is found only in late garnet–clinopyroxene exoskarn assemblages.     

界牌岭锡矿床蚀变矿化分带及其成因探讨

湖南界牌岭锡矿床蚀变矿化可分为条纹状云母萤石岩化—铍矿化带,细脉状云母萤石化—铅锌矿化带、黄玉—萤石—云英岩化—锡铜锌多金属矿化带和弱—无蚀变矿化带.不同蚀变矿化带物质组分迁移规律有不同的特点.其成矿物质主要来源于花岗斑岩,该矿床是与陆壳重熔型花岗岩类斑岩体有成因联系的斑岩型锡矿床.     

基于测井系列校正的趋势面分析法标准化研究

对测井资料进行标准化处理是地质精细解释的前提,不仅能提高测井资料的准确性,并且能保障测井解释精度。本文采用趋势面分析法对测井资料进行标准化。在进行第一次标准化处理时,由于研究区内新老井应用多种测井系列测量,出现了由测井系列差异引起的异常点。因此,将测井系列校正纳入标准化处理流程,即当工区开发历时较久、范围较大、测井系列较多时,在测井资料标准化之前必须先进行测井系列校正;提出了测井系列校正的方法,应用该方法对测井资料校正后,再进行第二次标准化处理。其结果检验表明,处理后的测井信息更加符合区域地质规律,证明该思路符合实际需求,能更加准确地完成区块测井资料的标准化,可以推广至全区及其它类似工区。     

Possible stellar asterisms carved on a protohistoric stone

Chisel marks on a stone uncovered in Rupinpiccolo protohistoric hill fort from north-eastern Italy were suggested to be a representation of the night sky (Bernardini et al. 2022 Documenta Praehistorica XLIX). The patterns of the 29 marks are analyzed here to establish if they reproduce popular stellar asterisms. Nine marks are found to match the Tail of Scorpius and five the Orion's Belt, together with Rigel and Betelgeuse. Nine marks are found in the approximate position of the Pleiades showing some match with the cluster members. On the back side, 5 marks possibly reproduce Cassiopeia. One mark slightly North of Orion cannot be identified. The 28 marks show a Pearson correlation coefficient $$(28) with stellar positions higher than 0.99 with a probability $$ of a wrong correlation lower than 0.001. Departures are about one degree, or about 7 mm, as the mean diameter of the marks, which suggests a manufacturing limitation in the charting. The fort dates $$1800–400 BCE when Scorpius and Orion showed about the same orientation at the heliacal rising. The unidentified mark challenges the whole picture. We suggest it could have been the progenitor of a failed supernova, thus offering also the possibility of a verification.