Fahlore and Sphalerite from the Darasun Gold Deposit in the Eastern Transbaikal Region,Russia: I. Mineral Assemblages and Intergrowths,Chemical Composition,and Its Evolution     

N. G. Lyubimtseva  N. S. Bortnikov  S. E. Borisovsky  V. Yu. Prokofiev  O. V. Vikent’eva 《Geology of Ore Deposits》2018,60(2):93-120

The mineral assemblages, mode of occurrence, and chemical compositions of coexisting fahlore and sphalerite from the Darasun gold deposit have been described. Three generations of fahlore and three generations of sphalerite have been recognized. The FeS content in sphalerite coexisting with fahlore ranges from 0.8 to 9.4 mol %. The complete solid solution series Fe-tetrahedrite–Zn-tetrahedrite–Fe-tennantite–Zn-tennantite reflected in Sb/(Sb + As) and Fe/(Fe + Zn) ratios ranging from 0 to 0.97 and from 0.07 to 1.00, respectively, with a predominant negative relationship between these ratios has been identified for the first time at the deposit. Stepped, oscillatory, and combined stepped-oscillatory growth zonings within fahlore grains and heterogeneous aggregates of fahlore have been found. Fahlore is enriched in As with respect to Sb, and Zn-tetrahedrite is followed by Fe- and Zn-tennantite from early to late generation; Zn-tetrahedrite is followed by Fe-tennantite in zoned grains and overgrown rims; sphalerite crystallized at decreased temperature and sulfur fugacity. The evolution of the chemical composition of fahlores was caused by the evolving temperature, fluid salinity, and conditions of metal migration.  相似文献   

基于GRACE-FO的微波与激光星间测距数据的重力场模型对比分析     

朱紫彤  闫易浩  梁磊  穆庆禄  王长青  冯伟  钟敏 《大地测量与地球动力学》2022,42(12):1262-1268

为分析GRACE-FO微波测距系统KBR及激光干涉测距系统LRI对时变重力场结果的影响,以动力学方法为基础,分别采用KBR数据和LRI数据反演2019-01~2021-08的90阶无约束时变重力场模型APM_KBR和APM_LRI,并进行对比分析。 从重力场模型阶方差和等效水柱高的空间分布来看,在两类测距数据完整且质量较好的前提下,两者精度处于同一水平,而当发生较多月卫星机动或其他卫星事件时会使LRI数据缺失,从而导致APM_LRI模型在该月得到的等效水柱高时间序列信噪比略低。由后验残差结果可知,APM_LRI后验残差RMS比APM_KBR减少约50%,且在高频处(大于等于60 CPR)LRI的后验残差显著低于KBR。总体来说,在现有条件下,由于背景场模型等其他因素影响,两类测距数据反演重力场的阶方差和等效水柱高结果基本一致,但后验残差上LRI测距具有更低的噪声。因此,未来可直接使用LRI测距数据探测、分析较弱的地球物理信号。  相似文献   

Phospholipid Compositions in Portunus trituberculatus Larvae at Different Developmental Stages     

LU Zhibin  SHI Ce  LIU Lei  MU Changkao  YE Yangfang  WANG Chunlin 《中国海洋大学学报(英文版)》2022,21(1):152-162

Phospholipids are used to improve the growth and survival of Portunus trituberculatus,a widely cultured crab species in China.However,only total phospholipids or several classes are applied in crab diets.In this study,we employed a targeted lipidomic method to investigate the comprehensive phospholipid composition in P.trituberculatus larvae and reveal the changing phospholipid profile over the larval development.Results showed that P.trituberculatus larvae contain 112 phospholipid species belonging to 10 phospholipid classes,in which phosphatidylcholine(PC)and phosphatidylethanolamine(PE)species are the most abundant,and PC,PE,phosphatidic acid,and phosphatidylserine(PS)are with high concentrations.The levels of all phospholipids significantly changed with larval development,which was highlighted by the downward parabolic changes in PE,phosphatidylglycerol,phosphatidylino-sitol,PS,lysophosphatidic acid,and sphingomyelin levels.In addition,nearly all phospholipid species were depleted at the M stage,which probably contributed to the mass mortality of crab larvae.These findings on the composition and alterations of phospholipids in P.trituberculatus larvae provide novel perspectives for the targeted supplementation of phospholipids in crab diets.Our work also highlights the use of targeted UHPLC-MS lipidomics in understanding the changes of phospholipids during crab development.  相似文献   

Effect of Long-Term Low-Salinity Culture on the Survival,Growth, and Nutrient Composition of Mud Crab Scylla paramamosain     

JI Zilu  LI Ronghua  WANG Chunlin  ZHANG Zhouyi  ZHANG Weijia  MU Changkao  SONG Weiwei 《中国海洋大学学报(英文版)》2022,21(1):179-185

This study investigated the effects of long-term low-salinity on the growth performance,proximate composition,amino acid and fatty acid profiles of Scylla paramamosain.The salinity of the low-salinity-culture group(LC)and maintained-salinity-cul-ture group(MC)were set at 5 and 25 respectively.After rearing for 30 d,the survival rate(SR)of the LC group was significantly lower,whereas the average daily molting frequency(ADMF)was significantly higher than those in MC group(P<0.05).There were no significant difference for weight gain rate(WGR)and specific growth rate(SGR)between the two groups.The moisture content of the LC group was slightly higher than the MC group without significant difference.The contents of ash,crude lipid and crude pro-tein in the LC group were lower than those in the MC group,but no significant differences were found except for ash content.A total of 17 free amino acids and 23 fatty acids were identified from the muscle of S.paramamosain.The total amino acids(TAA),essen-tial amino acids(EAA)and essential amino acid index(EAAI)had no significant difference between the two groups.The crabs from LC group had a significantly higher HUFA,including EPA,DHA,ARA.The percentage of n-3 PUFA and the ratio of n-3/n-6 PUFA were significantly higher in the LC group.These results indicated that S.paramamosain rearing at low salinity had significantly de-creased SR;however,the low-salinity environment significantly promoted the accumulation of unsaturated fatty acids(UFAs),espe-cially the n-3 PUFA,which might be related to the osmoregulation mechanism.  相似文献   

基于动态树结构的河网分析方法     

艾自兴  牛瑞芳  毋河海  谌虎 《测绘科学》2006,31(3):80-81

某条河流除了河流自身的数量与质量特征外,该河流在河网结构中的空间位置及其相关结构特征将提供全局性的评价依据。河网的空间形态结构特征由各条河流的几何特征和河流之间的相互关系决定,为了完整表示河网的空间形态结构特征,本文提出了基于动态树结构的河网分析思想,阐述了动态河网树结构的建立、维护及其应用的方法。  相似文献   

Erratum to: The Khuvsgul Earthquake of January 12, 2021 (MW = 6.7, ML = 6.9) and Early Aftershocks     

Emanov  A. F.  Emanov  A. A.  Chechel’nitskii  V. V.  Shevkunova  E. V.  Radziminovich  Ya. B.  Fateev  A. V.  Kobeleva  E. A.  Gladyshev  E. A.  Arapov  V. V.  Artemova  A. I.  Podkorytova  V. G. 《Izvestiya Physics of the Solid Earth》2022,58(3):443-443

Izvestiya, Physics of the Solid Earth - An Erratum to this paper has been published: https://doi.org/10.1134/S1069351322100019  相似文献   

Granitoids of the Kongo Magmatic Zone of the Omolon Massif (Northeastern Russia): Rock Composition,Age, and Geodynamic Setting     

Glukhov  A. N.  Kotov  A. B.  Priymenko  V. V.  Sal’nikova  E. B.  Ivanova  A. A.  Plotkina  Yu. V.  Fedoseenko  A. M. 《Geotectonics》2022,56(2):178-190

Geotectonics - In our study we analyzed the composition of granitoid rocks within the Kongo magmatic zone of the Omolon median mass. The studied calc-alkaline granitoids cut through the Early...  相似文献   

Streamflow of Russian Rivers under Current and Forecasted Climate Changes: A Review of Publications. 1. Assessment of Changes in the Water Regime of Russian Rivers by Observation Data     

Frolova  N. L.  Magritskii  D. V.  Kireeva  M. B.  Grigor’ev  V. Yu.  Gelfan  A. N.  Sazonov  A. A.  Shevchenko  A. I. 《Water Resources》2022,49(3):333-350

Water Resources - Publications on changes in river water regime in Russia under the conditions of current climate changes are reviewed. Most recent generalizations of such publications are...  相似文献   

冻融循环作用下木质素磺酸钙改良黄土的力学特性研究     

黄雨灵  张吾渝  季港澳  解邦龙  董超凡 《冰川冻土》2022,44(6):1863-1874

木质素磺酸钙作为一种绿色环保的改良材料,近年来被应用于土体加固领域。为探究木质素磺酸钙对黄土的固化效果,通过开展侧限浸水压缩试验、冻融循环试验、不固结不排水三轴剪切试验、扫描电镜试验和X射线衍射试验,分析冻融循环次数、掺量和围压对木质素磺酸钙改良黄土力学性质和微观机理的影响规律。研究结果表明：掺入木质素磺酸钙,可有效消除黄土的湿陷性。此外,改良黄土的应力-应变曲线随木质素磺酸钙掺量的增加向一般硬化型转变,而随着冻融循环次数的增加,应力-应变曲线向弱硬化型转变。改良黄土的破坏强度随木质素磺酸钙掺量的增加呈先增大后减小的趋势,木质素磺酸钙掺量为1%时破坏强度最高,各掺量改良黄土随冻融循环次数的增加先减小后趋于稳定,同时抗剪强度指标呈现下降的趋势。通过扫描电镜试验和X射线衍射试验,发现改良黄土内部有胶结物生成并填充了土颗粒间的孔隙,使土体密实度提高,进而提高土体强度;而冻融作用导致土颗粒的接触方式由面-面接触向点-点、点-面接触过渡。此外,木质素磺酸钙改良黄土中未发现有新的矿物成分生成,且冻融作用未造成土体矿物成分的消解。  相似文献   

Modelling of Soil Degradation in Semi-arid Area Using Remote Sensing and GIS Techniques,Southern Jordan As Case Study     

Al-Mashagbah  Atef Faleh  Ibrahim  Majed  Al-Fugara  A’kif  Alayyash  Saad  Mabdeh  Ali Nouh 《Doklady Earth Sciences》2022,507(2):1169-1180

Doklady Earth Sciences - This research dealt with the topic of modeling the soil lost in a semi-arid desert area in the Ma’an watershed and its surroundings in Ma’an Governorate using...  相似文献