Preliminary assessment of CO2 transport and storage costs of promising source–sink matching scenarios in Guangdong province,China

Guangdong is the most economically developed province in China, which is a large CO₂ emitter and hence is faced with severe carbon reduction pressures. In this paper, a cost assessment methodology based on scenario analysis is presented. A CO₂ source and sink database was built at Guangdong after detailed investigations on the point sources and sedimentary basins. Fifteen transport and five storage scenarios were defined and studied, respectively. Cost estimates based on these scenarios show that during its lifetime, the costs of both transport and storage depend on the amount of CO₂ processed. More CO₂ being processed will bring down the unit costs of both transport and storage. However, it was observed that there is a cost inflection point between the storage amount of 35.2 and 52.8 Mt/year, which means that as the storage amount increases, the storage cost will first decrease and then increase. Source region S1 in Guangdong has been recommended for an early chance of CO₂ storage. Preliminary cost comparisons have shown that the results presented in this study are reasonable, but to improve the cost assessment accuracy of offshore CO₂ storage, a methodology based on a CO₂ storage design that can integrate local prices needs to be further developed.     

Assessment of soil salinization based on a low-cost method and its influencing factors in a semi-arid agricultural area,northwest China

An investigation of soil salinization was carried out in the Nanshantaizi area (Northwest China) with WET Sensor. This device can measure such soil parameters as bulk soil electrical conductivity, water content, and the pore water electrical conductivity that are important for soil salinization assessments. A distribution map of soil salinization was produced, and the factors influencing soil salinization and its processes were discussed in detail. The study shows that moderately salinized to salt soils are mainly observed in the alluvial plain, where groundwater level is high and lateral recharge water contains high salinity. Nanshantaizi is covered by slightly salinized soils. The soil salinization distribution estimated by WET Sensor is generally consistent with the actual levels of salinization. Soil salinity in Nanshantaizi is mostly of natural origin and accumulated salts could leach to deeper soils or aquifers by water percolation during irrigation. Groundwater evaporation, groundwater level depth and quality of recharge water are important factors influencing soil salinization in the alluvial plain.     

Spatial heterogeneous response of land use and landscape functions to ecological restoration: the case of the Chinese loess hilly region

Ecological restorations over time may have profound effects on ecological and socio-economic systems. However, land-use changes and landscape functions that accompany ecological restorations can have spatial differentiations due to varied biophysical and socio-economic contexts. Therefore, these spatial differentiations caused by ecological restoration must be understood for better planning and management of restoration activities. The Baota District, with 576 villages in the center of the Chinese Loess Plateau, was selected as the study area because of its dramatic transition from cropland to grassland and shrubland from 1990 to 2010. Using the ArcGIS software and a k-means clustering analysis, an approach to identify types of land-use change patterns (TLCPs) at the village level was developed, and four TLCPs were delineated. The analysis indicated a general pattern of cropland decline by 21.6 %, but revealed significant spatial variations between villages in different TLCPs. Vegetation cover and soil retention, which are key proxies for landscape functions, increased by 22.70 and 108 %, respectively, from 2000 to 2010 with significant spatial heterogeneity. The Universal Soil Loss Equation was employed for the assessment of soil retention. The analysis of landscape metrics revealed a major trend of fragmentation and regularity on the county and village scale; however, spatial variations remained. Physical attributes were used to characterize different TLCPs, and notable differences were found. The spatial heterogeneous change in land use and landscape functions on the village scale may be useful for land use and ecological restoration management policy makers.     

内蒙古八大关斑岩型铜钼矿床成岩成矿年代学研究

八大关斑岩铜钼矿床是中国内蒙大兴安岭地区典型的斑岩型铜钼矿床之一。对矿区Ⅱ号岩体不同位置的2件岩石样品采用高精度的LA_ICP_MS锆石U_Pb测年,获得的锆石U_Pb年龄分别为(230.6±2.8)Ma和(230.5±4.4)Ma,两者在误差范围内非常一致,由此确认花岗闪长斑岩体的形成年龄约为230 Ma;对矿区7件辉钼矿样品采用Re_Os同位素测年,获得的Re_Os等时线年龄为(228.7±3.1)Ma,指示了八大关铜钼矿床辉钼矿的沉淀时间约为228.7 Ma。结合矿区岩相学、矿物学特征,辉钼矿呈浸染状分布于花岗闪长斑岩体内,且辉钼矿与黄铜矿密切共生,以及上述2种精确方法获得的年龄在误差范围内的一致性,说明花岗闪长斑岩即为成矿岩体,成岩与成矿大致同时或成矿略晚于成岩,表明八大关铜钼矿床形成于中三叠世,属于印支期成矿。     

云南中甸红牛-红山矽卡岩型铜矿床矿物学特征与成矿作用

红牛-红山矿床位于西南三江成矿带的中甸岛弧,是形成于晚燕山期的矽卡岩型铜矿床。矿区与成矿作用密切相关的石英二长斑岩中角闪石和黑云母斑晶的出现以及较高的含F量(分别为1.49%和2.62%),表明其岩浆为富H2O富挥发分熔体;石英斑晶具有港湾状、浑圆状的溶蚀表面和钾长石细晶外壳,并且显示了典型的骸晶状结构指示了其岩浆经历了快速上升侵位过程和岩浆热液的自交代作用;钻孔中岩浆热液角砾岩和大量石英细脉的出现暗示了岩浆在快速上侵过程中发生了隐爆作用,形成并出溶了含有大量F、Cl等组分的高盐度超临界流体。矽卡岩阶段石榴子石和透辉石具有明显的三个期次:早期细粒的钙铝榴石(And22-57)和角岩中的透辉石(Hd7-27)形成于少量高温气液岩浆流体与围岩的扩散交代作用;中期粗粒的钙铁榴石(And75-98)和次透辉石-钙铁辉石(Hd10-99)形成于大量高温、低氧逸度的岩浆流体与围岩的渗滤交代作用;晚期的钙铝榴石脉(And14-60)和钙铁辉石脉(Hd31-58)形成于低温、高氧逸度的早期交代残留溶液。矽卡岩矿物的生成,使碳酸盐围岩丢失CO2,矿物体积减少,孔隙度和渗透性增加,为成矿提供了条件。退化变质阶段的透闪石、阳起石、绿帘石、绿泥石等交代早期矽卡岩矿物,消耗了成矿流体中大量的CO2和H2O,生成含水矿物以及石英、方解石,使围岩裂隙愈合,孔隙流体压力增加,导致成矿流体沸腾,形成大量黄铜矿、磁黄铁矿、黄铁矿、辉钼矿化。石英-硫化物阶段,由于成矿流体超压→流体沸腾,裂隙生成→减压排泄,裂隙愈合→流体超压的循环,在此过程中围岩经历了多次破裂和裂隙的愈合,直至整个成矿体系完全开放,并与大气水发生混合,使成矿流体中剩余金属最终沉淀。     

高放废物地质处置北山预选区旧井和新场花岗岩填隙方解石同位素地球化学

为了探讨高放废物地质处置甘肃北山预选区旧井和新场预选地段的古地下流体来源、成因、化学演化历史以及水-岩相互作用,文章系统研究了该地段花岗岩填隙方解石的产出特征及其碳、氧、锶同位素的组成特征。测试结果表明,旧井和新场方解石的δ13 C组成均较稳定且为负值(分别为-11.6‰~-5.7‰和-9.9‰~-5.1‰);δ18 O分别为-0.7‰~19.7‰和10.9‰~21.9‰,旧井方解石具有更宽的δ18 O取值范围。87 Sr/86 Sr也略有差异,旧井为0.708584~0.718749,新场为0.708838~0.732967,二者随深度增加而呈明显的降低趋势。研究表明,北山预选区地下流体来源及成因较复杂,浅部地下水受大气降水的影响较大,深部流体则主要源于地下咸水,为低温流体蚀变成因。花岗岩裂隙中的水-岩反应强度总体较弱,地下水环境相对稳定。相比较而言,新场岩体深部的地球化学环境更稳定,更有利于高放废物的长期处置。     

新疆喀拉通克铜镍矿田成矿条件、岩浆通道与成矿潜力分析

位于中亚造山带北缘的喀拉通克早二叠世铜镍硫化物矿区是新疆规模最大的铜镍矿山,包含13个岩体,相当部分为隐伏岩体,其中1号、2号、3号、9号矿床为主力矿床,经过30余年持续开发,最大开采深度已达740 m,已面临后备资源不足的危机。已知矿体主要产于辉长岩、苏长岩、辉长苏长岩以及橄榄苏长岩中,甚至角闪辉长岩局部也含矿,未见超镁铁岩产出,具有显著的磁性(200 nT)、重力(0.29×10~(-5)m/s~2)、激化率异常,以镁铁岩含矿、岩体规模小且成群成带、分异演化程度高、富铜(Cu/Ni约3:2)、PGE较高、块状硫化物贯入矿体普遍发育为特色。其围岩为含炭质板岩、片岩和凝灰岩,变形强烈,常规电法受到炭质层的干扰。依据岩石学、地球化学研究,岩浆源于软流圈地幔,基于与东天山同期铜镍矿床含矿岩相及其比例和剩余重力异常的比较,推断其应发育有相当比例的超镁铁岩,因而深部出现超基性岩的可能性很高,且含矿性应更好。这一推断得到坑道钻探的证实,2013年矿区在Y2岩体东段650~740 m深度和Y2岩体西段400~500 m深度发现隐伏超镁铁岩且含矿,局部见贯入块状矿体。橄榄辉石岩、辉石橄榄岩系矿区首次发现,粒度很细,发育强烈的蛇纹石化、纤闪石化,推测只是隐伏超基性岩的头部。结合控岩控矿构造的追溯及南、北岩带的侧伏和倾伏方向判断,硫化物珠滴构造的发现与系统观测统计,围岩烘烤边和角岩化的研究分析,提出南岩带主岩浆通道位于Y2与Y3岩体之间,而不是原普遍认为的岩浆通道位于Y1与Y2岩体之间。结合矿区的现状,提出采用高分辨率浅层地震、CSAMT和瞬变电磁地-井测量,结合传统的高精度重力勘探、磁法勘探和激发极化法来勘探和预测南岩带深部隐伏含矿超镁铁岩的空间位置和产状,圈定岩浆通道和隐伏铜镍矿体,进而推动北岩带和外围G21、22号岩体的深部探矿工作。     

黑龙江乌拉嘎金矿成矿热力学参数研究

本文通过对前人工作的总结,在研究矿物共生关系的基础上将乌拉嘎金矿床的成矿作用过程划分为3个成矿阶段,然后利用热力学数据计算出了各个阶段的成矿热力学参数。第1阶段:黄铁矿-早期白色玉髓状石英阶段,Eh范围在-0.5~+0.3 V之间,处于弱还原环境,硫逸度应大于10~(-23);第2阶段:烟灰色玉髓状石英-多金属硫化物阶段,在低温时成矿环境为中酸性(pH=4),弱还原环境(Eh值为-1.0~-0.3 V),硫逸度范围应大于10~(-40),但不会超过10~0。同前一阶段相比,硫逸度下限降低;第3阶段:碳酸盐-石英阶段,碳酸盐矿物的出现预示着成矿已接近尾声,成矿介质的pH值逐步从酸性(pH=3)向中酸性(pH=5)转变,成矿Eh值也从弱还原(-0.5 V)向弱氧化(+0.3 V)过渡,硫逸度下限范围大约在10~(-23)左右,不超过10~0,而氧逸度范围在10~(-20)加左右。这对于深入探讨热液成矿作用过程具有重要参考价值。     

Levels and distributions of polycyclic aromatic hydrocarbons (PAHs) in middle reach of Huaihe River,China: anthropogenic influences and ecological risks

Polycyclic aromatic hydrocarbons (PAHs) are a group of aromatic hydrocarbons with high toxicity to human health. PAH emissions from industrial activities have become the primary sources of PAH contamination in Chinese watersheds. Here, we analyzed 10 individual priority PAHs in 120 water samples taken from middle reach of Huaihe River, China. The results show that the PAH levels in studied watershed are significantly lower as compared to other Chinese watersheds, approaching or slightly exceeding the PAH levels in watersheds from selected European and North American countries. We observe rather large variation in spatial and vertical PAH distributions, pointing to PAH inputs from local industrial emissions, and PAH cycle among atmosphere, water and sediment. Individual PAH ratios (i.e., phenanthrene/anthracene and fluorene/pyrene) and principal components analysis suggest a primarily pyrolytic PAH sources (combustion of coal and coke) in water column. Other accompanying PAH sources include emissions from steel industry and gasoline. Total toxic benzo[a]pyrene equivalent of PAHs in studied water column indicates that PAHs in watershed of middle reach of Huaihe River pose limited toxicity to the environment.     

Determination of trace and rare-earth elements in Chinese soil and clay reference materials by ICP-MS

Inductively coupled plasma mass spectrometry(ICP-MS) has become a powerful tool for providing reliable analytical results in many laboratories around the word. In this study, the mixture of HF and HNO3 acids in high-temperature and high-pressure closed-vessel digestion technique were used to decompose some Chinese reference materials, and thirty seven elements were determined by ICP-MS. Most of the results for Chinese soil reference materials were found to be in reasonable agreement with the reference values, except Cs, Ta, Li, Ge, Zn, Nd, Tb and Ta whose values need to be revised. Their precisions were typically lower than 5% RSD. However, the Precisions of Chinese clay reference materials, especially for GBW03102 and GBW03102a, were significantly different with reference values, probably reflecting the existence of a coarser-grained fraction(70 μm) in samples, and the formation of fluorides in Al-rich samples during sample decomposition by using the mixture of HF and HNO3 acids. Moreover, thirty-seven trace elements covering the mass range from Li to U in four Chinese clay reference materials were firstly provided with good precision and accuracy in this study.