CO2吸附对煤岩热弹性模型影响的理论解释

引入煤岩对气体的吸附势函数，并假定吸附势函数是引起多孔介质变形和应力的一个因素，给出了考虑CO2吸附的煤岩热弹性模型的一般形式，分析了CO2吸附对煤岩热弹性模型的影响。结果表明，在弹性范围内，吸附势函数是通过改变热传导方程和热传导的热力学限制条件来间接影响介质的应力和变形的。而对应力一应变之间的关系表达式的形式没有影响。一旦给出自由能函数和吸附势函数的形式，就可以确定考虑气体吸附条件下介质的热弹性本构模型。     

Heterogeneous lithospheric mantle metasomatism in the eastern North China Craton: He–Ar isotopes in peridotite xenoliths from Cenozoic basalts

The abundances and isotopic compositions of Helium and Argon have been analyzed in a suite of fresh spinel peridotite xenoliths in Cenozoic basalts from the eastern North China Craton (NCC) by step-wise heating experiments, to investigate the nature of noble gas reservoirs in the subcontinental lithospheric mantle beneath this region. The xenoliths include one harzburgite collected from Hebi in the interior of the NCC, two lherzolites from Hannuoba at the northern margin of the craton, and three lherzolites from Shanwang and Nushan on the eastern margin. ³He/⁴He ratios in most of the xenoliths are similar to those of mid-ocean ridge basalts (MORB) or slightly lower (2–10.5 Ra, where Ra is the ³He/⁴He ratio of the atmosphere), suggesting mixing of MORB-like and radiogenic components. One olivine separate from Nushan has a helium value of 25.3 Ra, probably suggesting cosmogenic ³He addition. The ⁴⁰Ar/³⁶Ar ratios vary from atmospheric value (296) to 1625, significantly lower than the MORB value. Available data of the peridotite xenoliths indicate the He and Ar isotopic systematics of the mantle reservoirs beneath the NCC can be interpreted as mixtures of at least three end-members including MORB-like, radiogenic and atmospheric components. We suggest that the MORB-like noble gases were derived from the underlying asthenosphere during mantle upwelling, whereas the radiogenic and recycled components probably were incorporated into the lithospheric mantle during circum-craton subduction of oceanic crust. Available data suggest that the MORB-like fluids are better preserved in the interior of the NCC, whereas the radiogenic ones are more prevalent at the margins. The Paleo-Asian ocean subduction system probably was responsible for the enriched and recycled noble gas signatures on the northern margin of the craton, while the Pacific subduction system could account for the observed He–Ar isotopic signatures beneath the eastern part. Therefore, integration of helium and argon isotopes reflects heterogeneous metasomatism in the lithospheric mantle and demonstrates the critical importance of lithospheric mantle modification related to both circum-craton subduction of oceanic crust and asthenospheric upwelling beneath the eastern NCC.     

亚热带小流域花岗岩化学风化及CO2消耗速率研究

文章选择深圳市的亚热带典型小流域作为研究对象,通过定期采集流域内降水、泉水、岩石及风化残积土样品,分析所有样品的常量元素和微量元素,探讨流域水体的化学成分组成和主要成分来源以及岩石化学风化程度和风化趋势,结合流域水文气象数据估算了花岗岩化学风化速率及CO2消耗速率.结果表明,研究区地下水化学类型为HCO3-Na型,主要...     

白垩纪中期海相富有机碳沉积的地球生物学背景

白垩纪中期(约125～88Ma)海相富有机碳沉积广泛发育于全球各主要洋盆和沉降区,是许多大油田的重要烃源岩。文中从地球生物学的角度探讨了当时海相富有机碳沉积的地质背景和主控因素,认为在白垩纪中期全球事件频发的特殊背景下,保存条件(大洋缺氧)和生产力的提高共同控制了有机质的富集。大洋缺氧不但加快了海洋生物的灭绝和更替,使有机质大量堆积,而且促进了营养元素(P、N、Fe等)的再生和厌氧自养型海洋微生物(如蓝细菌、绿硫细菌和古菌类等)的极度繁盛,提高了生产力水平;而高的生产力又反过来加剧了海洋的缺氧。新的研究成果(Os同位素证据)表明,白垩纪大规模海底火山作用引发了持续的温室效应和海水循环的静滞、紊乱以及弱上升流发育,进而导致生产力的提高和大洋缺氧事件(OAE)的发生,最终造成有机质的广泛堆积和保存。     

藏南措美残余大火成岩省的西延及意义

在西藏南东部和澳大利亚南西部新识别出的早白垩世Comei-Bunbury大火成岩省的范围还未能得到很好约束。为探讨这一问题,本文报道了西藏南东部浪卡子-洛扎以西、江孜、康马地区广泛分布的近东西向基性岩墙和少量玄武岩的岩石学和地球化学数据。这些以辉绿岩、辉长岩为主的镁铁质岩石属于碱性-亚碱性玄武岩系列,在地球化学上主要包括高Ti的洋岛玄武岩型和低Ti的大洋中脊玄武岩型,两者的εNd(t)值分别为(+0.9～+2.0)和(+4.6～+5.8)。这两种类型岩石的地球化学特征均与措美残余大火成岩省内的对应类型可比,暗示它们与措美残余大火成岩省一样,均形成于由地幔柱作用于大陆岩石圈引起的伸展背景,代表该残余大火成岩省的西延。本文研究结果使得现今保留在特提斯喜马拉雅带上的Comei-Bunbury大火成岩省的残余面积接近50000km2。该大火成岩省的大规模岩浆活动可能是引发研究区甚至全球早白垩世大洋缺氧事件的一个重要因素。     

CO2浓度梯度对两种岩溶微藻碳酸酐酶活性的影响

以经岩溶水驯化的小球藻（Chlorella vulgaris）和喜钙念珠藻(Nostoc calcicola Breb.)为实验对象,在封闭体系中用Willbur和 Anderson 方法比较研究两种不同微藻在不同CO2浓度下碳酸酐酶活性变化情况。结果表明:在低于3%CO2浓度的环境中岩溶微藻可通过快速调节自身碳酸酐酶活性来应对CO2升高带来的生境影响,在影响最大的2.5%的环境下小球藻与喜钙念珠藻碳酸酐酶活性分别提高了1.46倍和2.12倍;岩溶微藻应对CO2浓度增大带来的pH下降有着重要的恢复作用,随培养时间增长培养环境中的pH得到恢复;随着CO2浓度的增大,岩溶因子对碳酸酐酶有着重要的影响;培养48 h时Ca2+与喜钙念珠藻碳酸酐酶的相关性最高,而电导率（EC）与小球藻碳酸酐酶相关程度最高。      

数值模拟在CO2地质封存示范项目中的应用

CO2深部咸水层地质封存被认为是减缓温室效应的一种有效的工程技术手段。针对神华鄂尔多斯105 t/a CO2捕集与封存(CCS)示范项目,用数值模拟方法对CO2在地层中的运移过程进行了详细地刻画,分析了CO2的流动迁移、地层压力积聚过程及地层封存潜力。数值模型不但可以为工程的顺利进行提供技术支撑,而且可以节省人力财力。首先,根据实际监测数据对模拟参数进行校准,得到了合适的压力拟合曲线,确定了主要的水文地质参数。然后,对为期3 a的CO2续注工程进行预测,详细分析了CO2的晕扩散、溶解情况、地层压力变化情况、储层封存潜力等。得到如下结论：CO2在3 a内的最大迁移距离约为350 m;水裂可以有效提高CO2的注入性;隔离层能有效防止CO2逃逸。研究表明,尽管鄂尔多斯盆地属于低渗咸水层仍然能够有效安全地封存CO2。     

Assessment of the biospheric contribution to surface atmospheric CO2 concentrations over East Asia with a regional chemical transport model

A regional chemical transport model, RAMS-CMAQ, was employed to assess the impacts of biosphere–atmosphere CO2 exchange on seasonal variations in atmospheric CO2 concentrations over East Asia. Simulated CO2 concentrations were compared with observations at 12 surface stations and the comparison showed they were generally in good agreement. Both observations and simulations suggested that surface CO2 over East Asia features a summertime trough due to biospheric absorption, while in some urban areas surface CO2 has a distinct summer peak, which could be attributed to the strong impact from anthropogenic emissions. Analysis of the model results indicated that biospheric fluxes and fossil-fuel emissions are comparably important in shaping spatial distributions of CO2 near the surface over East Asia. Biospheric flux plays an important role in the prevailing spatial pattern of CO2 enhancement and reduction on the synoptic scale due to the strong seasonality of biospheric CO2 flux. The elevation of CO2 levels by the biosphere during winter was found to be larger than 5ppm in North China and Southeast China, and during summertime a significant depletion( 7 ppm) occurred in most areas,except for the Indo-China Peninsula where positive bioflux values were found.     

Planktic Foraminiferal Biostratigraphy of the Cretaceous Oceanic Red Beds in Kangmar,Southern Tibet,China

The planktic foraminifera of the Chuangde Formation (Upper Cretaceous Oceanic Red Beds, CORBs) as exposed at Tianbadong section, Kangmar, southern Tibet has been firstly studied for a detailed for a detailed biostratigraphy elaboration. A rich and well-preserved planktic foraminifera were recovered from the Chuangde Formation of the Tianbadong section and the Globotruncanita elevata, Globotruncana ventricosa, Radotruncana calcarata, Globotruncanella havanensis, Globotruncana aegyptiaca, Gansserina gansseri and Abathomphalus mayaroensis zones have been recognized. The planktic foraminiferal assemblage points to an early Campanian to Maastrichitian age for the CORBs of the eastern North Tethyan Himalayan sub-belt, which also provides a better understanding of the shifting progress of the Indian Plate to the north and the evolution of the Neotethyan ocean. The lithostratigraphy of the Chuangde Formation of the Tianbadong section comprises two lithological sequences observed in ascending succession: a lower unit (the Shale Member) mainly composed of purple (cherry-red, violet-red) shales with interbedded siltstones and siliceous rocks; and an upper unit (the Limestone Member) of variegated limestones. The strata of the Chuangde Formation in the Tianbadong section are similar to CORBs in other parts of the northern Tethyan Himalaya area of Asia (Gyangze, Sa’gya, Sangdanlin, northern Zanskar, etc.). The fossil contents of the Chuangde Formation in the sections (CORBs) studied provide a means of correlation with the zonation schemes for those of the northern Tethyan Himalayan sub-belt and the Upper Cretaceous of the southern Tethyan Himalayan sub-belt. Paleogeographic reconstruction for the Late Cretaceous indicates that the Upper Cretaceous Chuangde Formation (CORBs) and correlatable strata in northern Zanskar were representative of slope to basinal deposits, which were situated in the northern Tethyan Belt. Correlatable Cretaceous strata in Spiti and Gamba situated in the southern Tethyan Belt in contrast were deposited in shelf environments along the Tethyan Himalayan passive margin. CORBs are most likely formed by the oxidation of Fe(II)-enriched, anoxic deep ocean water near the chemocline that separated the oxic oceanic surface from the anoxic.