粤东塘唇石英脉型钨(锡)矿床地质特征、成矿时代及其找矿意义

塘唇钨(锡)矿是近年来新发现的一个具有大型规模找矿潜力的石英脉型矿床.矿床产于粤东龙窝花岗闪长岩岩体西部外接触带,赋矿地层为下侏罗统金鸡组碎屑岩,该层位是南岭及邻区石英脉型钨锡矿的最新赋矿地层.在详细的野外地质调查基础上,对矿床含钨石英脉中的白云母进行⁴⁰Ar-³⁹Ar测年,获得白云母⁴⁰Ar-³⁹Ar坪年龄为150±1 Ma,等时线年龄为149±2 Ma(MSWD=1.20),它们在误差范围内一致,为南岭地区燕山早期大规模成岩成矿作用高峰期的产物.塘唇钨(锡)矿的发现,不仅拓宽了石英脉型钨锡矿的找矿视野,还有助于完善石英脉型钨锡矿成矿规律和成矿模式,对区域下一步找矿具有重要指导意义.     

Heating duration of igneous rim formation on a chondrule in the Northwest Africa 3118 CV3oxA carbonaceous chondrite inferred from micro-scale migration of the oxygen isotopes

Due to their common occurrence in various types of chondrites, igneous rims formed on pre-existing chondrules throughout chondrule-forming regions of the solar nebula. Although the peak temperatures are thought to reach similar values to those achieved during chondrule formation events, the heating duration in chondrule rim formation has not been well defined. We determined the two-dimensional chemical and oxygen isotopic distributions in an igneous rim of a chondrule within the Northwest Africa 3118 CV3_oxA chondrite with sub-micrometer resolution using secondary ion mass spectrometry and scanning electron microscopy. The igneous rim experienced aqueous alteration on the CV parent body. The aqueous alteration resulted in precipitation of the secondary FeO-rich olivine (Fa_40–49) and slightly disturbed the Fe-Mg distribution in the MgO-rich olivine phenocrysts (Fa_11–22) at about a 1 μm scale. However, no oxygen isotopic disturbances were observed at a scale greater than 100 nm. The MgO-rich olivine, a primary phase of igneous rim formation, has δ¹⁷O = −6 ± 3‰ and δ¹⁸O = −1 ± 4‰, and some grains contain extreme ¹⁶O-rich areas (δ¹⁷O, δ¹⁸O = ∼−30‰) nearly 10 μm across. We detected oxygen isotopic migration of approximately 1 μm at the boundaries of the extreme ¹⁶O-rich areas. Using oxygen self-diffusivity in olivine, the heating time of the igneous rim formation could have continued from several hours to several days at near liquidus temperatures (∼2000 K) in the solar nebula suggesting that the rim formed by a similar flash heating event that formed the chondrules.     

广东河台整装勘查区百旁金矿成矿规律

百旁金矿是广东地质五队近年来新发现的一处中型蚀变糜棱岩型金矿。百旁金矿地处粤西—桂东成矿带东段NE向罗定—广宁断裂带北东端部位,矿体受糜棱岩带内面理、裂隙带控制;金矿化具明显的以硅化、硫化物为中心的对称性分布特征,金矿体具有平行斜列、侧伏的分布规律,表现为向NE向侧伏;区内金矿化富集主要与热液活动有关,燕山期的重熔花岗岩侵入的同时伴随有富含硫化物的含金热液充填在糜棱岩、断裂带内而成矿。     

Dynamic Relationship Between Entrainment Rate and Summer Monsoon in the Transition Area of Monsoon in the East of Northwest China

Entrainment rate refers to the ratio of surrounding air quality to air quality involved in rising unit distance, including turbulent entrainment and dynamic entrainment, which are applied to the boundary layer parametrization of convective clouds, the improvement of numerical model, the observation of cloud droplet spectral dispersion and the study of tropical cyclones.Based on the daily data at 07:00 and 19:00 every 10 m of five stations such as Minqin, Yuchong, Pingliang, Yinchuan and Yan'an from May to September during 2006-2016, combined with the daily observation data on the ground, the Entrainment Rates(ER) of different heights were calculated, and the relationships between ER and height in different regions, precipitation as well as monsoon during the monsoon period were further obtained. The main results were as follows:\mathrm{①} The ER was proportional to air temperature and saturated water vapor pressure, but inversely proportional to relative humidity. The relative humidity threshold of cloud was 65%. The higher the relative humidity threshold was, the lower the cloud height of different orders of precipitation was, and the cloud height was higher with the increase of rainfall. \mathrm{②}ER had obvious diurnal changes and regional differences: It was obviously smaller at 07:00 than at 19:00 from ground to 3 km, which weakened with the increase of height in the near surface , but strengthened with the increase of height above 500 m; From small to large, the monsoon affected area, the monsoon swing area and the non-monsoon area were in turn, and there was no regional difference above 3 km. \mathrm{③} ER was closely related to the intensity and property of precipitation in monsoon period. The ER weakened with the enhancement of rain intensity from near ground to below 600 m, but strengthened with the enhancement of rain intensity from 500 m to 2~3 km.From near ground to below 700 m, the ER of stable precipitation was strong, but that of convective precipitation was strong above 700 m. The convective precipitation had big saturated water vapor pressure and strong ER , while the stable precipitation had big saturated water vapor density, rich water vapor but weak ER. \mathrm{④}The relationship between ER and monsoon as well as its duration: From no monsoon to monsoon ER was weakened, the strongest maximum height was also decreasing. There was no significant difference in the duration of ER between the non-monsoon area and the monsoon affected area, but the longer the monsoon swing area lasted in the near ground layer, the smaller the ER was, while the opposite was at 1~2 km in the high altitude. \mathrm{⑤}The relationship between ER and the APO monsoon intensity index showed that: At 07:00, the ER strengthened with height from near ground to below 800 m, but weakened with height above 800 m,and the monsoon intensity was not related to the ER. At 19:00, the ER strengthened with the height near ground but weakened with the height above 300 m, and the stronger the monsoon was, the smaller the ER was. The ER weakened with the decrease of boundary layer height.     

Genesis of the Xiuwenghala Gold Deposit in the Beishan Orogen,Northwest China: Evidence from Geology,Fluid Inclusion,and H–O–S–Pb Isotopes

The Xiuwenghala gold deposit is located in the Beishan Orogen of the southern Central Asian Orogenic Belt. The vein/lenticular gold orebodies are controlled by Northeast‐trending faults and are hosted mainly in the brecciated/altered tuff and rhyolite porphyry of the Lower Carboniferous Baishan Formation. Metallic minerals include mainly pyrite and minor chalcopyrite, arsenopyrite, galena, and sphalerite, whilst nonmetallic minerals include quartz, chalcedony, sericite, chlorite, and calcite. Hydrothermal alterations consist of silicic, sericite, chlorite, and carbonate. Alteration/mineralization processes comprise three stages: pre‐ore silicic alteration (Stage I), syn‐ore quartz‐chalcedony‐polymetallic sulfide mineralization (Stage II), and post‐ore quartz‐calcite veining (Stage III). Fluid inclusions (FIs) in quartz and calcite are dominated by L‐type with minor V‐type and lack any daughter mineral‐bearing or CO₂‐rich/‐bearing inclusions. From Stages I to III, the FIs homogenized at 240–260°C, 220–250°C, and 150–190°C, with corresponding salinities of 2.9–10.9, 3.2–11.1, and 2.9–11.9 wt.% NaCl eqv., respectively. The mineralization depth at Xiuwenghala is estimated to be relatively shallow (<1 km). FI results indicate that the ore‐forming fluids belong to a low to medium‐temperature, low‐salinity, and low‐density NaCl‐H₂O system. The values decrease from Stage I to III (3.7‰, 1.7–2.4‰, and ?1.7 to 0.9‰, respectively), and a similar trend is found for their values (?104 to ?90‰, ?126 to ?86‰, and ?130 to ?106‰, respectively). This indicates that the fluid source gradually evolved from magmatic to meteoric. δ³⁴S values of the hydrothermal pyrites (?3.0 to 0.0‰; avg. ?1.1‰) resemble those of typical magmatic/mantle‐derived sulfides. Pyrite Pb isotopic compositions (²⁰⁶Pb/²⁰⁴Pb = 18.409–18.767, ²⁰⁷Pb/²⁰⁴Pb = 15.600–15.715, ²⁰⁸Pb^/204Pb = 38.173–38.654) are similar to those of the (sub)volcanic ore host, indicating that the origin of ore‐forming material was mainly the upper crustal (sub)volcanic rocks. Integrating evidence from geology, FIs, and H–O–S–Pb isotopes, we suggest that Xiuwenghala is best classified as a low‐sulfidation epithermal gold deposit.     

我国西北地区21世纪季节气候变化情景分析

使用各国政府间气候变化专门委员会(IPCC)数据分发中心提供的7个全球海气耦合气候系统模式(CCC、CCSR、CSIRO、DKRZ、GFDL、HADL、NCAR)的模拟结果,对我国西北地区未来21世纪考虑温室气体增加(GG)和温室气体与硫化物气溶胶共同影响(GS)时,冬夏季的气候变化情景进行了分析.模式集成结果分析表明,我国西北地区的变暖趋势与全球、东亚和中国一致,但变暖幅度明显高于全球、东亚和中国.对未来100年各个季节线性倾向的分析表明,西北地区GG和GS时都是冬季变暖最大,可高达5～8℃/100a,且整个西北地区中新疆地区为最大变暖区.21世纪由于人类活动,西北地区最低温度和最高温度都将明显升高,其线性趋势可达4～6℃/100 a.由于全球气候模式对区域尺度的模拟存在较大的不确定性,未来需要作更多的深入研究.     

GEOCHEMISTRY

正20141357 Guo Tao(School of Mathematics and Science,Shijiazhuang University of Economics,Shijiazhuang 050031,China);Hu Jiawen Assessment on the New Pressure-Volume-Temperature(PVT) Data of Supercritical Water(Geological Journal of China Universities,ISSN1006-7493,CN32-1440/P,19(3),2013,p.447-455,9 illus.,3 tables,32 refs.)Key words:supercritical fluids     

PETROLEUM GEOLOGY

正20140890 Bai Ru(National Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi’an 710069,China);Zhang Jingong Characteristics of Pore Character and Its Controls of Chang 6Reservoir of Zhiluo Oilfield(Journal of Northwest University,ISSN1000-274X,CN61-1072/N,     

迁徙中的承袭、交融与分异——广东客家建筑与聚落形态时空发展解析

客家是一支在一定时期内处于流迁状态的民系。在其迁徙过程中,宗族组织化的群体自身的文化惯性对撞地理环境与社会环境的差异,使客家民系对于生存空间关系的处理呈现多样的态度。为厘清广东主要客居地内不同传统客家村居形态之间的关联性及其发展脉络,本研究从类型学角度,分别在微观建筑形态与中观聚落格局两个层面,依据关键空间属性来划分空间形制的基本类型,并整理比较建筑类型与聚落类型的地理分布。而后,从历史地理学角度挖掘客家民系在广东省内的流迁历程,并顺沿多条流迁动线分别探讨不同建筑类型、不同聚落类型之间的承袭、交融与分异关系,进而得出以下结论：① 在“建筑”与“聚落”两个尺度层面上的空间营造活动中,建筑形制决策倾向于依附民系内生文化,聚落模式决策倾向于呼应局域地区的社会经济与自然环境;② 在沿迁徙路径的时空推移过程中,主要建筑类型沿主干河流由上游向中下游传播承袭,韩江水系和东江水系之间的支线水陆途径促进了建筑类型在规模、围合防卫程度、聚合组织形式等方面的渐变过渡;③ 相对于客家文化核心区,“广府-客家”“福姥-客家”文化锋面上客家建筑“中轴”对空间组织的主导力发生急剧弱化,意味着宗族组织出现扁平化的变化态势,主要表现为该地带宗族“房系”发达度下降,以及宗祠的经济文化凝聚力衰退;④ 从空间概念的历时性承袭与发展视角来看,空间形态控制性基因应为明确的“属性”化因子,而非具象化要素,聚居空间的基因分析,应当分别基于“人”“地”的不同线索,探索不同尺度人居空间形态的控制因子。     

热带气旋直接降水对中国的影响研究

本文基于RSMC台风最佳路径资料以及TRMM逐日降水资料,对1998—2013年间中国区域热带气旋(TC)直接降水的时空分布特征进行了统计研究。结果表明:约54.2%的西北太平洋TC在中国陆地上产生了直接降水。TC直接降水对中国的影响范围较广,未变性TC的降水决定了全部TC降水的西界,而潜在变性TC的降水决定了全部TC降水的北界。自每年的4月开始,TC直接降水开始影响中国,以8月最为频繁,潜在变性TC的影响以9月为最。降水首日,全体TC以台风及以上强度为主,中心主要分布在30°N以南。未变性的TC强度较弱,降水面积大、降水强度强;而潜在变性TC则以台风(TY)及以上强度为主,其单个TC的平均降水面积和降水强度以热带低压(TD)及以下强度TC为最大。本文工作为TC在中国直接降水的气候特征以及TC变性前期降水分布特征提供了一些有意义的结论。