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961.
硫循环及硫同位素(δ34S)分馏研究对地表圈层的成岩作用具有重要意义,其中多种金属硫化物中硫同位素的分馏程度可以约束成矿热流体温度,进而作为地温计证据约束热液活动。四川盆地龙王庙组储集层内的热液改造影响着该储集层的非均质性,本研究着重讨论目的层中与热液成因白云石所伴生的黄铁矿(FeS2)-黄铜矿(CuFeS2)成矿现象:基于详尽的岩石学证据,应用纳米二次离子探针(NanoSIMS)对金属硫化物内部硫同位素分布进行测定,并基于热力学驱动下的硫化物间平衡分馏程度计算其成矿温度,进而约束层段内热液活动过程。研究发现:(1)微区硫同位素分布显示黄铁矿(FeS2)与黄铜矿(CuFeS2)沉淀过程中不仅存在热力学分馏,还存在动力学分馏现象,其中动力学分馏程度可以达到40.1‰,应用NanoSIMS微区测定手段可以有效剔除动力学分馏数据影响,获取热力学平衡分馏数据;(2)黄铁矿(FeS2)与黄铜矿(CuFeS2)成矿过程或利用不同的硫源,其中黄铁矿...  相似文献   
962.
The western Qinling orogen (WQO) is one of the most important prospective gold provinces in China. The Maanqiao gold deposit, located on the southern margin of the Shangdan suture, is a representative gold deposit in the WQO. The Maanqiao deposit is hosted by the metasedimentary rocks of the Upper Devonian Tongyusi Formation. The EW-trending brittle-ductile shear zone controls the orebodies; they occur as disseminated, and auriferous quartz–sulfide vein. The ore-related hydrothermal alteration comprises silicification, sulfidation, sericitization, chloritization, and carbonatization. Native gold is visible and mainly associated with pyrite and pyrrhotite. Mineralization can be classified into the following three stages: bedding-parallel barren quartz–pyrite–(pyrrhotite) (early-stage), auriferous quartz–polymetallic (middle-stage), and carbonate–(quartz)–sulfide (late-stage).Detailed fluid inclusion (FI) studies revealed three types of inclusions in quartz and calcite: aqueous (W-type), CO2–H2O (C-type), and pure carbonic (PC-type) FIs. The primary FIs in the early-stage quartz are C- and PC-type, in the middle-stage quartz are mainly W- and C-type, and in the late-stage calcite are only W-type. During gold mineralization, the total FI homogeneous temperatures evolved from 189–375 °C (mostly 260–300 °C) to 132–295 °C (mostly 180–240 °C) to 123–231 °C (mostly 130–150 °C), and the salinities varied among 2.2–9.1 wt.% NaCl equiv. (mostly 5–8 wt.%) to 0.2–9.0 wt.% NaCl equiv. (mostly 3–6 wt.%) to 0.3–3.6 wt.% NaCl equiv. (mostly 2–4 wt.%). The ore-forming fluid was characterized as an H2O–NaCl−CO2−CH4–(N2) system with medium-low temperature and low salinity. The fluid immiscibility and fluid-rock interaction may be responsible for the precipitation of the sulfides and gold at the Maanqiao gold deposit. Three types of pyrite corresponding to the three mineralization stages, as well as pyrrhotite and arsenopyrite in the middle stage, are micro-analyzed for in-situ sulfur isotopic composition by LA-ICP-MS. Py1 yield near-zero δ34S values of −2.5‰ to 3.0‰, which are somewhat lower than that of the granite hosted pyrites (Py-g, 4.8‰ to 6.6‰). The result suggests a mixed sulfur source from magmatic-hydrothermal fluids and the metamorphism of diagenetic pyrite. Pyrite + pyrrhotite + arsenopyrite assemblages in the middle-stage have relatively higher δ34S values (6.6‰ to 12.3‰) and are mainly developed due to the metamorphism of the ore-host and underlying Devonian sedimentary sequences. The low δ34S values of the late-stage fracture-filled Py3 (−21.9‰ to −17.0‰) resulted from an increasing oxygen fugacity, which was caused by the inflow of oxidized meteoric waters.Based on our studies, the Maanqiao gold deposit is considered to be an orogenic type and closely related to the Indosinian Qinling orogeny.  相似文献   
963.
农药污染地块修复过程中频繁出现异味污染问题,严重影响周边居民日常生活和身体健康。以往报道多集中在场地内有毒有害物质分析,较少关注场地异味污染问题。为预测某有机磷农药场地修复过程异味污染情况,本文以该地块7个潜在异味污染控制区为研究对象,分析了近土壤空气异味污染程度和影响范围,并应用气相色谱-四极杆/静电场轨道阱高分辨质谱技术测定近土壤空气、土壤中挥发性有机物(VOCs)和半挥发性有机物(SVOCs),阐明地块控制区内异味污染排放特征,评估近土壤空气地块污染的人体健康风险。结果表明,7个区域监测点位散发不同程度刺激性气味,臭气浓度值范围为309~72443;生产区异味影响范围最大,达到3.2km;共识别出近土壤环境空气中209种VOCs、土壤样品中246种VOCs和SVOCs,主要包括芳香化合物、卤代物、烷烯烃和含氧有机物;主要异味贡献物质种类包括有机硫化物、芳香化合物和含氧有机物;7个区域近土壤空气均存在致癌风险(>1.0×10-4),5个区域存在非致癌风险,主要致癌物质为1,4-二氯苯、苯、四氯化碳。本文开展的农药场地异味物质组分与致病致癌风险持续研究结果,可为研究区生态环境修复和居民健康保护等提供重要依据。  相似文献   
964.
陆相断陷咸化湖盆有机质差异富集因素探讨   总被引:1,自引:0,他引:1  
我国中、新生代陆相断陷咸化湖盆广泛发育含盐泥页岩,蕴藏着大量页岩油资源。页岩油“甜点”发育与有机质富集密切相关,但含盐泥页岩有机质差异富集主控因素研究相对较少,且存在争议。以渤海湾盆地东濮凹陷为例,针对古近系沙三段泥页岩取芯,开展总有机碳(TOC)、扫描电镜、能谱分析以及主量、微量和稀土元素分析,探讨泥页岩的有机质丰度与古气候、古盐度、沉积速率、古生产力和氧化还原条件的关系。结果表明:沙三段泥页岩的有机质富集主要受控于古生产力、古盐度和沉积速率。古生产力越大,有机质富集程度越高;随古盐度和沉积速率升高,有机质富集程度先增大后减小。氧化还原条件对有机质富集的影响不大,这与泥页岩整体发育于缺氧的还原条件有关。只有在高的古生产力、适当的古盐度和适当的沉积速率背景下,方才利于沉积有机质富集。泥页岩的有机质差异富集是非常规油气沉积学研究的重要内容之一,揭示有机质差异富集主控因素,对我国陆相页岩油勘探开发具有重要意义。  相似文献   
965.
李志扬 《沉积学报》2021,39(1):168-180
传统的沉积模式认为大部分细粒沉积岩(泥岩或页岩)的沉积发生在相对深水、低能的环境中。作为地表上分布最为广泛的沉积岩类型,泥页岩包含了对重构地质历史时期古地理、古气候的重要信息。泥页岩除了可以作为有效的烃源岩,勘探开发技术的进展更发掘出泥岩作为非常规油气储层的巨大潜力。近十年来,国内外对细粒沉积物的水槽实验、泥岩沉积微相的精细分析、以及泥岩岩相组成特征的研究取得了长足的进展。这些研究对泥岩的沉积过程和沉积模式在不同角度上提供了新的认知。大部分泥岩(甚至包括众多有机质含量高的泥岩)都可能沉积在相对浅水以及水动力条件相对较高的环境中。不同的沉积过程(底部水流)形成不同的泥岩沉积微相,并对有机质在泥岩中的埋藏富集具有重要的控制作用。以晚白垩纪北美西部内陆海道为例,总结在陆棚浅海环境中(最大水深< 200 m),位于从近岸到远岸(> 500 km)不同沉积环境(包括前三角洲/下邻滨、内陆棚、中陆棚、和外陆棚环境)中的泥岩的主要沉积过程、沉积微相特征、以及富集有机质的潜力。由于沉积过程和沉积环境是决定泥岩成分、沉积相、和岩石物理特征非均质性的首要因素,不同浅海环境中的泥岩相特征和沉积模式可有助于利用泥岩地层进行古地理、古气候的重构,并能够对预测不同陆棚浅海环境中沉积的泥岩作为有效烃源岩或有效储层的潜力提供指导。  相似文献   
966.
有机质孔隙是页岩储集空间的重要组成部分,具有强烈的非均质性,阻碍对页岩储层质量的正确认识和评价,其本质是受有机显微组分类型及其在生烃过程中孔隙演化的影响。本文采用场发射扫描电镜和荧光显微镜定位观察手段实现特定显微组分孔隙发育特征的表征,结合Image J图像处理技术,对不同演化阶段的显微组分进行定量化统计,总结不同有机显微组分的孔隙演化规律。研究结果表明:固体沥青孔隙度随着成熟度的升高呈现先增加后减小的趋势,在固体沥青反射率SBR_O介于1.6%~2.0%时,固体沥青孔隙最为发育,而以SBR_O=2.0%为界,固体沥青孔隙度开始减小。镜质体和惰质体的孔隙发育规律相似,随着成熟度增加,总体表现出先减小而后微弱增加的趋势。在生油窗阶段,镜质体和惰质体孔隙度最小,无机矿物和固体沥青的充填使胞腔孔隙损失达90%以上,而进入高成熟阶段,固体沥青孔隙的发育使原始胞腔孔隙得到一定程度的恢复,成为镜质体和惰质体残余孔隙的主要贡献者,贡献率达56.73%和100%,可见固体沥青孔隙对页岩储层储集空间的重要性。综合沉积成岩作用和生烃作用,页岩储层在未成熟阶段和高成熟阶段晚期孔隙最为发育,前者有机质以原始胞腔孔隙为主,后者以固体量孔隙为主。明确有机显微组分孔隙演化规律为页岩有利储层预测和页岩气生产开发储层改造提供参考。  相似文献   
967.
Long-term changes of composition,sources and burial fluxes of TOC(total organic carbon) in sediments of the central Yellow Sea mud area and their possible affecting factors are discussed in this paper.Firstly,similarity analysis is employed to confirm that the carbon burial features resulted from two collected cores are typical in the central Yellow Sea mud area where YSWC(Yellow Sea Warm Current) is prevalent.On this basis,the burial flux of TOC here was considered to be 235.5–488.4 μmol/(cm2?a) since the first industrial revolution,accounting for about 70%–90% among burial fluxes of TC(total carbon) in the sediments.Compared TOC/TC ratio in the two cores with that in other marine sediments worldwide,we suggest that the growth of calcareous/non-calcareous organisms and dissolution of IC(inorganic carbon) are important factors controlling the TOC/TC ratio in sediment.Results of two-end mixed model based on δ13C data indicate that marine-derived organic carbon(OCa)is the main part among total burial organic carbon which accounts for a ratio over 85%.Due to the high TOC/TC ratio in the two cores,TC in the sediments also mainly exists as OCa,and the proportion of OCa is about 60%–80%.Away from the shore and relatively high primary production in upper waters are the main reasons that OCa is predominant among all burial OC in sediments of the central Yellow Sea mud area.Burial of OC in this mud area is probably mainly influenced by the human activities.Although the economic development during the late 19 th century caused by the first industrial revolution in China did not obviously increase the TOC burial fluxes in the sediments,the rise of industry and agriculture after the founding of new China has clearly increased the TOC burial flux since 1950 s.Otherwise,we also realize that among TC burial fluxes,TIC account for about 10%–30% in sediments of the central Yellow Sea mud area,so its burial could not be simply ignored here.Distinct from TOC burial,long-term TIC burial fluxes variations relate with climate changes more closely:the East Asian summer monsoon may influence the strength of the Huanghe River(Yellow River) flood,which could further affect the transport of terrestrial IC from land to the central Yellow Sea as well as the burial of these IC in the sediments.  相似文献   
968.
Inorganic nutrient contents of mucus released by Acropora corals and its utilization by heterotrophic bacteria at several different hour intervals in the coral mucus were investigated at a coral reef in Malaysia. The dissolved inorganic phosphate (DIP) concentration was 135‐fold higher than in the ambient seawater, probably due to inorganic P release from the coral gut cavity. We experimentally confirmed that heterotrophic bacteria rapidly (within 8 h) consumed ca. 80% of the initial concentration of DIP derived from coral mucus. High DIP concentration in coral mucus may enhance heterotrophic bacterial production and associated carbon flow in the microbial loop of reef ecosystems.  相似文献   
969.
1980~2010年华北平原农田土壤有机碳的时空变化   总被引:2,自引:0,他引:2  
利用农业生态系统过程模型(Agricultural Production Systems s IMulator,APSIM),研究了1980~2010年间中国华北平原农田土壤有机碳(Soil Organic Carbon,SOC)的时空变化。模型验证结果表明,校正后的APSIM模型总体能够较好地模拟徐州、郑州和昌平3个长期定位试验站点中各处理下小麦和玉米的产量变化以及SOC的变化。区域模拟结果显示,1980~2010年间华北平原大部分农田SOC呈增加趋势,仅河北省的北部、山东省中部和东部部分地区农田SOC减少。华北平原总的农田面积约为24.52 Mha(1 ha=0.01 km2),其SOC密度的平均变化速率为0.35 Mg(C)ha-1 a-1,总的SOC贮量增加了约257.43 Tg。在京津冀地区、山东省以及河南省的农田中,SOC分别平均增加了102.05、59.82、95.56 Tg。SOC的增加,主要归功于过去几十年里外源碳投入量的增加。  相似文献   
970.
In the present research, laundry wastewater treatment is studied using the electrocoagulation/electroflotation process. For the optimization of treatment conditions such as electrode type (Al–Al, Al–Fe, Fe–Fe, and Fe–Al), initial pH (5–9), current (0.54–2.16 A), and application time (15–60 min), response surface methodology is used. Removal efficiencies of chemical oxygen demand (COD), color, anionic surfactant, microplastic, and phosphate are studied. It is determined that the most effective removal is obtained with 2.16 A current, pH 9, and 60 min reaction time using Fe–Al electrode. Here, 91%, 94%, 100%, and 98% removal efficiencies are achieved for COD, surfactant, color, and microplastic, respectively. The operating cost of the combined process is calculated as $1.32 m?3 for the optimum removal parameters. The adsorption kinetics study shows that the removal follows second‐order kinetics. The laboratory‐scale test results indicate that the electrocoagulation/electroflotation process is feasible for the treatment of laundry wastewater.  相似文献   
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