Origin of the Tongshankou porphyry–skarn Cu–Mo deposit,eastern Yangtze craton,Eastern China: geochronological,geochemical, and Sr–Nd–Hf isotopic constraints

The Tongshankou Cu–Mo deposit, located in the westernmost Daye district of the Late Mesozoic Metallogenic Belt along the Middle-Lower reaches of the Yangtze River, eastern China, consists mainly of porphyry and skarn ores hosted in the Tongshankou granodiorite and along the contact with the Lower Triassic marine carbonates, respectively. Sensitive high-resolution ion microprobe zircon U–Pb dating constrains the crystallization of the granodiorite at 140.6 ± 2.4 Ma (1σ). Six molybdenite samples from the porphyry ores yield Re–Os isochron age of 143.8 ± 2.6 Ma (2σ), while a phlogopite sample from the skarn ores yields an ⁴⁰Ar/³⁹Ar plateau age of 143.0 ± 0.3 Ma and an isochron age of 143.8 ± 0.8 Ma (2σ), indicating an earliest Cretaceous mineralization event. The Tongshankou granodiorite has geochemical features resembling slab-derived adakites, such as high Sr (740–1,300 ppm) and enrichment in light rare earth elements (REE), low Sc (<10 ppm), Y (<13.3 ppm), and depletion in heavy REE (<1.2 ppm Yb), and resultant high Sr/Y (60–92) and La/Yb (26–75) ratios. However, they differ from typical subduction-related adakites by high K, low MgO and Mg#, and radiogenic Sr–Nd–Hf isotopic compositions, with (⁸⁷Sr/⁸⁶Sr) _t  = 0.7062–0.7067, ɛ _Nd(t) = −4.37 to −4.63, (¹⁷⁶Hf/¹⁷⁷Hf) _t  = 0.282469–0.282590, and ɛ _Hf(t) = −3.3 to −7.6. The geochemical and isotopic data, coupled with geological analysis, indicate that the Tongshankou granodiorite was most likely generated by partial melting of enriched lithospheric mantle that was previously metasomitized by slab melts related to an ancient subduction system. Magmas derived from such a source could have acquired a high oxidation state, as indicated by the assemblage of quartz–magnetite–titanite–amphibole–Mg-rich biotite in the Tongshankou granodiorite and the compositions of magmatic biotite that fall in the field between the NiNiO and magnetite–hematite buffers in the Fe³⁺–Fe²⁺–Mg diagram. Sulfur would have been present as sulfates in such highly oxidized magmas, so that chalcophile elements Cu and Mo were retained as incompatible elements in the melt, contributing to subsequent mineralization. A compilation of existing data reveals that porphyry and porphyry-related Cu–Fe–Au–Mo mineralization from Daye and other districts of the Metallogenic Belt along the Middle-Lower reaches of the Yangtze River took place coevally in the Early Cretaceous and was related to an intracontinental extensional environment, distinctly different from the arc-compressive setting of the Cenozoic age that has been responsible for the emplacement of most porphyry Cu deposits of the Pacific Rim.     

Assessment of second- and third-order ionospheric effects on regional networks: case study in China with longer CMONOC GPS coordinate time series

Higher-order ionospheric (HOI) delays are one of the principal technique-specific error sources in precise global positioning system analysis and have been proposed to become a standard part of precise GPS data processing. In this research, we apply HOI delay corrections to the Crustal Movement Observation Network of China’s (CMONOC) data processing (from January 2000 to December 2013) and furnish quantitative results for the effects of HOI on CMONOC coordinate time series. The results for both a regional reference frame and global reference frame are analyzed and compared to clarify the HOI effects on the CMONOC network. We find that HOI corrections can effectively reduce the semi-annual signals in the northern and vertical components. For sites with lower semi-annual amplitudes, the average decrease in magnitude can reach 30 and 10 % for the northern and vertical components, respectively. The noise amplitudes with HOI corrections and those without HOI corrections are not significantly different. Generally, the HOI effects on CMONOC networks in a global reference frame are less obvious than the results in the regional reference frame, probably because the HOI-induced errors are smaller in comparison to the higher noise levels seen when using a global reference frame. Furthermore, we investigate the combined contributions of environmental loading and HOI effects on the CMONOC stations. The largest loading effects on the vertical displacement are found in the mid- to high-latitude areas. The weighted root mean square differences between the corrected and original weekly GPS height time series of the loading model indicate that the mass loading adequately reduced the scatter on the CMONOC height time series, whereas the results in the global reference frame showed better agreements between the GPS coordinate time series and the environmental loading. When combining the effects of environmental loading and HOI corrections, the results with the HOI corrections reduced the scatter on the observed GPS height coordinates better than the height when estimated without HOI corrections, and the combined solutions in the regional reference frame indicate more preferred improvements. Therefore, regional reference frames are recommended to investigate the HOI effects on regional networks.     

冰湖的界定与分类体系——面向冰湖编目和冰湖灾害研究

冰川湖泊（简称冰湖）不仅是高山区重要的水资源,而且是许多冰川灾害的孕育者和发源地,在冰冻圈科学、气候变化和山地灾害研究中具有重要地位。本文系统讨论了现有冰湖定义及存在的问题,从冰湖编目和冰湖灾害研究视角提出冰湖的定义,指出现有冰湖研究主要是基于“以现代冰川融水为主要补给源或在冰碛垄洼地内积水形成的天然水体”这一冰湖定义的。同时,从冰湖形成机理、地貌形态和空间分布位置将冰湖划分为冰川侵蚀湖（冰斗湖、冰川槽谷湖和其他冰川侵蚀湖）、冰碛阻塞湖（终碛阻塞湖、侧碛阻塞湖、冰碛垄热融湖）、冰川阻塞湖（冰川前进阻塞湖和其他冰川阻塞湖）、冰面湖、冰下（内）湖和其他冰川湖6大类及8个亚类,并给出各冰湖类型相应的遥感判识指标和定量指标,以期建立具有普适性和可操作性的冰湖分类体系。     

产业转型背景下创业区位选择和集群空间演化

以广州软件和信息技术产业集群为案例,分析产业范式转变背景下地方创业区位选择对产业集群空间演化的影响。结果显示：初始资源富集和政策环境导向使特定空间成为创业的优势区位,早期第一代创业企业在其中集聚发展形成集群雏形,并在关系网络和区域认同作用下形成产业集群空间核心区。第二代创业企业在产业转型契机下选择开拓缝隙市场,新的区位诉求由此产生并作用在集群的空间演化上。总的来说,产业转型期同时也是集群空间转变的关键时期,创业企业通过区位选择可以改变集群的空间形态和层次。     

太行-五台山区不同时代花岗岩类岩石学和地球化学的特征对比及陆壳演化

通过对太行－五台山区太古宙、元古宙和中生代等不同时代的花岗岩类岩石学和地球化学特征的对比，并将晚太古时期花岗岩类同国内外同时期花岗岩类进行对比，确定了本区晚太古时期花岗岩类岩石组合为英云闪长岩－奥长花岗岩－花岗闪长岩或英云闪长岩－奥长花岗岩－花岗闪长岩－花岗岩，并以奥长花岗岩演化趋势为主，叠加了部分钙碱性演化；而元古宙、中生代花岗岩类岩石组合则主要为花岗闪长岩－花岗岩或花岗岩，以钙碱性演化趋势为特征。可以认为晚太古时期的太行－五台山区正处于陆壳演化的初始阶段和成熟阶段之间的过渡性阶段。     

洞庭湖地区地球化学土壤质量分区及评价

该文根据营养元素的含量，对洞庭湖地区的土壤质量进行了优、劣分区。在优势区可以少施或免施钙镁磷肥，在劣势区应少施有机肥和磷肥，多施氮、钾肥及多元素复合肥。     

塔里木古生界残余盆地的油气资源及勘探前景

塔里木盆地是多旋回叠合盆地,主要烃源岩为奥陶系和寒武系,其古生界盆地经历过海西早期、海西晚期和燕山晚期等三期主要构造运动,现今具典型的残余盆地性质。开发了三维油气盆地定量描述和动态模拟软件系统,对塔里木盆地进行了全面研究。三期构造运动所剥蚀的(古生界)排油气损失量之和约占累积排油气量的12%左右。其中以海西早期剥蚀的排油气损失量最大,达263×10~8t;奥陶系排油气损失最严重,其次为寒武系。塔里木盆地的油气资源潜量仍十分巨大,油127×10~8t,气68×10~8t 油当量。含四个石油资源潜量富集区,按强度依次为满加尔蚴陷、唐古巴斯坳陷、阿瓦提坳陷和巴楚隆起;天然气资源潜量富集区三个,依次为满加尔坳陷、唐古巴斯坳陷和阿瓦提坳陷。且末北部有一个从石炭纪以来长期继承性发育的鼻状隆起带,是满加尔坳陷的油气运移指向地区,有可能形成大型复合油气田。     

环珠江三角洲大湾文化地貌试析

近十余年环珠江口地区５０００￣６０００年前的新石器时代遗址已发掘２０多处，其中１１个遗址是位于９个岛屿之上。这些考古学资料表明，６０００年前左右沿海居民海洋蛋白资源开拓的重要证据。     

图们江地区水资源现状,潜力及其对区域开发的影响

图们江地区４个市处于城市发展的初期阶段，污染企业较多，水域功能下降，水资源潜力退化明显，对区域开发和产业布局有重要影响。目前，珲春河水质较好，水量大，可为该区开发提供重要的水资源保证。因此，其开发的重点应以珲春市为热点区。     

金沙江流域水土流失及其防治措施

长江三峡水库入库站寸滩的水沙主要来源于长江上游金沙江和嘉陵江。其中多年平均径流量和输沙量的40.7％和52.7％来自金沙江,这对三峡水利枢纽工程关系重大。该江水土流失十分严重,且有加重趋势,这与人类活动有密切关系,对此提出五项防治措施。