Comparative petroleum hydrocarbons levels and biochemical responses in mussels from hydrothermal vents (Bathymodiolus azoricus) and coastal environments (Mytilus galloprovincialis)

Aliphatic hydrocarbons and PAHs in the whole soft tissues of Bathymodiolus azoricus from three Mid-Atlantic Ridge hydrothermal vents (Menez-Gwen, Lucky Strike and Rainbow), and Mytilus galloprovincialis from three contaminated coastal sites in South Portugal were analysed, and its effects on the digestive gland microsomes mixed-function oxygenase system (MFO) were assessed.Aliphatic hydrocarbons levels were present in the same magnitude in both coastal and hydrothermal environments, while the UCM (unresolved complex mixture) for coastal mussels were higher than in vent mussels. In general, significantly higher PAHs concentrations were found in coastal mussels, compared to B. azoricus where low molecular weight PAHs (2–3 rings) represented the majority of PAHs contrarily to what was observed in M. galloprovincialis. The MFO components were present in both mussel species, and were detected in vent mussels for the first time. However this system seems to have different roles in species from these contrasting environments. In coastal mussels MFO responded to hydrocarbon contamination while response in hydrothermal organisms appeared to be related mainly to endogenous factors.     

Detoxification mechanisms in shrimp: comparative approach between hydrothermal vent fields and estuarine environments

Hydrothermal vents are extreme deep-sea habitats that, due to their singular features, still intrigue scientific communities. Swift growth rates and profuse biomass of biological communities can be observed, despite of their inherently unstable physical-chemical and toxic conditions, indicating that organisms inhabiting this environment must be well adapted to these inhospitable conditions. The caridean shrimp, Chorocaris chacei, Mirocaris fortunata and Rimicaris exoculata, together with bathymodiolid mussels, dominate the vent fauna along the Mid-Atlantic Ridge (MAR). Crustacean species are widely used as biological indicators of environmental alterations, since they play a key ecological role as planktivorous grazers, epibenthic scavengers or as prey species. The biological consequences of the hydrothermal metal-rich environment in shrimp species are still largely unknown. Therefore, the aim of this study was the determination of the metal levels (Ag, Cd, Cu, Fe, Mn and Zn), metallothioneins (MT) and lipid peroxidation (LPO) in shrimp species collected in Rainbow, Lucky Strike and Menez-Gwen vent sites, in order to evaluate their different adaptation strategies toward metals when compared with two common coastal shrimp species (Palaemon elegans and Palaemonetes varians) from a fairly unpolluted estuarine system in south Portugal (Ria Formosa). Results show significant differences in metal concentrations, MT levels and lipid peroxidation between vent and coastal shrimp and also between shrimp species from the same site. This indicates that biochemical responses in both vent and coastal shrimp are affected not only by the environmental characteristics but also by inter-specific differences. Nevertheless, these responses apparently grant a successful adaptation for the survival in a metal-extreme environment.     

藏北羌塘盆地西部查桑地区结构及构造特征

通过对近年新获得的航磁、重力、大地电磁测深和地质等资料的综合研究揭示,羌塘西部隆起查桑段具有明显的南北分带、东西分块和垂向分层的结构、构造特征。该区总体由两(东部)、三(西部)个东西向展布的大型南倾构造块体推覆叠置而成,其间又被数条近南北向断裂分割为若干个断块。各块带出露地层时代、结构构造和地球物理场特征有较大差别。在查桑段及邻区,地壳中上部有两个低阻层,所在的深度分别为15±5km和约40km之下。壳内上部低阻层主要分布在查桑段及其以南,为各块体总体向北运动和逆掩叠覆之底部主拆离推覆面,该区各南倾大断裂均向下收敛并交会到该层。下部低阻层的展布超出了查桑段,向北已达北羌塘坳陷,其影响的范围可能更为广阔。此南北分带、多块叠置的结构和复杂多变的地球物理场特征,仅孤零零地出现在双湖—绒马之间,不具区域意义。其形成与该区东、西两侧中生代始存在的近南北向转换断层和晚古生代可能曾发育有裂谷之背景密切相关。该区段挤压变形和叠覆隆升,始于早白垩世羌塘盆地反转期;始新世以来,印度板块碰撞遂继续向北推挤,又得到进一步的发展、加强及改造。     

鄂尔多斯盆地中部上三叠统延长组物源方向分析与三角洲沉积体系

首次利用稀土元素和微量化学元素,分析鄂尔多斯盆地中部上三叠统延长组母岩类型和物源方向。研究表明盆地中部延长组砂岩和泥岩的稀土元素地球化学特征、REE分配模式及微量化学元素蜘蛛图解相同,表现为轻稀土富集,重稀土亏损,铕、铈元素亏损;REE分配模式均呈“右倾斜、LREE富集、HREE平坦”型;微量化学元素蜘蛛图解具“四峰三谷一平台”型,曲线呈阶梯状分布;砂岩和泥岩的地球化学特征、REE分配模式及微量化学元素蜘蛛图解与盆地东北缘的太古代、元古代变质岩相一致,而与火成岩的重稀土富集、轻稀土亏损、“V”字型REE分配模式和“三峰两谷”型、曲线呈“W”字型分布的蜘蛛图解的特征有显著的差别。说明延长组母岩是盆地东北缘的太古代、元古代变质岩,主要物源方向为北东向。依据物源方向、沉积环境、砂岩岩石学特征、砂岩稀土元素和微量化学元素的地球化学特征,将鄂尔多斯盆地中部上三叠统延长组沉积划分为两大三角洲沉积体系,即北东向的安塞三角洲沉积体系、志靖三角洲沉积体系、安边三角洲沉积体系和北西向的盐定三角洲沉积体系。在三角洲沉积体系划分的基础上,详细阐述了不同三角洲沉积体系的岩石学特征、稀土元素和微量化学元素的地球化学特征及延长组长6-长2期三角洲沉积体系的演化过程。     

塔里木盆地库车坳陷依奇克里克构造带侏罗系储层特征及成因

利用岩石薄片、物性等分析资料，对库车坳陷东部依奇克里克构造带低渗透储层特征及其成因进行了研究。依奇克里克构造带中下侏罗统储层岩石类型均为岩屑砂岩、含长石岩屑砂岩。岩石学总体特征为成分成熟度低，结构成熟度较高，岩石成分成熟度由北向南逐渐变好。储集空间类型在东西向也有所差异，东部吐格尔明地区主要为次生-原生孔隙型，西部依南地区主要为裂缝-次生孔隙型。储集性能平面非均质性较强，以低孔、低渗、特低孔、特低渗储层为主，东部吐格尔明地区明显优于西部依南地区。影响本区储集性能的主要因素有压实作用、沉积环境、岩石学特征、溶蚀作用及构造作用，但最主要的影响因素是埋藏压实作用，构造挤压作用的叠加加强了本区西部储层压实作用，但裂缝发育又使储集性能有所改善。     

河南泌阳凹陷老第三系核桃园组核二段沉积体系研究

核二段沉积时期泌阳凹陷总体处于从断陷向坳陷转换的过渡阶段。本文利用测井、钻井和C、O同位素等资料，研究了核二段各砂组沉积时期的沉积环境、相带分布、砂体展布以及沉积演化规律。核二段时期，泌阳凹陷发育5种沉积体系类型：辫状河三角洲、扇三角洲、正常三角洲、近岸水下扇和盐湖沉积体系。物源供给条件和古地形严格控制了泌阳凹陷各种沉积体系的发育。在陡坡带的中、西部地区发育扇三角洲沉积体系，而在陡坡带东部则发育近岸水下扇沉积体系；在东北部缓坡带发育辫状河三角洲，而在西北部缓坡带则发育正常曲流河三角洲。借用C、O同位素数据估算核二段沉积时期平均古水温为28.17 ℃，最高46.8 ℃；环境指标Z值平均为126.84，表明核二段整套地层都为盐湖咸水沉积条件。从纵向上δ¹³C、δ¹⁸O及Z、t演化看，核二段地层演化表现为两个旋回：从三砂组底到二砂组底部为第一次湖水变咸、湖盆收缩，从二砂组底部到核二段顶为第二次湖水变咸、湖盆收缩。     

渤海湾盆地南堡凹陷新近系馆陶组沉积特征

南堡凹陷位于渤海湾盆地黄骅坳陷北部，新近系馆陶组是该凹陷的重要勘探层段。馆陶组以辫状河沉积为主，中段发育曲流河沉积。其油气勘探的首要问题是优质储集砂体的精确对比及有利盖层分布预测。根据高分辨率层序地层学理论以及录井和测井资料，对馆陶组的层序地层样式、沉积特征和储盖组合进行了分析。研究结果表明，该地层具有两种短期旋回和四个中期旋回。在两种短期旋回中，一种是低可容纳空间的非对称旋回，另一种是高可容纳空间的对称旋回。四个中期旋回中，两个以上升半旋回为主体(MSC1、MSC2)，一个是对称旋回(MSC3)，一个以下降半旋回为主体(MSC4)。短、中期旋回均以非对称旋回为主。该地层的长期基准面具有缓慢上升而后快速下降的特点。从MSC1到MSC4旋回，沉积相呈现出冲积扇-辫状河→辫状河-曲流河→曲流河-辫状河相组合的演化过程。自北向南，各中期旋回的可容纳空间增大，沉积主体由砾质河道渐变为砂质河道。由于受基准面中期旋回格架控制，南堡凹陷馆陶组发育上、中、下三套储盖组合。上部储盖组合，因其储、盖层条件最好，应是馆陶组最重要的油气勘探层系。     

鄂西渝东地区石柱古隆起构造沉积演化

石柱古隆起区的构造演化可划分为加里东、海西—早印支、晚印支—早燕山、晚燕山—早喜马拉雅、晚喜马拉雅等五个阶段。海西期—早印支期、晚印支期—早燕山期是石柱古隆起形成并继承性发展的重要时期 ,发育了石炭系黄龙组、二叠系、三叠系、侏罗系等地层序列 ,厚度大于 5 - 0 0 0 -m ,形成了多套生、储、盖成藏组合。三叠纪末的挤压 (晚印支运动 )对石柱古隆起的叠加导致了古圈闭的最终形成 ,圈闭高度达 10 0 -m左右 ,隆起幅度达 4 0 0～ 5 0 0 -m左右。此时 ,下志留统、下二叠统烃源岩埋深均大于 2 - 6 0 0 -m ,已进入生气、生油高峰阶段。三叠纪及侏罗纪石柱古隆起是油气运移的有利指向区及聚集区 ,侏罗纪末—白垩纪 (燕山晚期 )则是石柱古隆起圈闭的油气重新运移聚集的重要时期。石柱古隆起及周缘地区成藏条件优越 ,区内现今的圈闭群可认为是天然气勘探的有利靶区。     

火山岩吸附CO_2气的成藏潜力及实例分析

火山岩的脱气实验和对昌德东CO2气藏气源的分析结果表明:加热火山岩到250℃时,脱出挥发分总量为0.0299～0.0790mL/g,其中CO2脱出量为0.0218～0.0706mL/g(0.429～1.387wt%);挥发组分以CO2为主,还含有H2、CO、CH4等还原性气体,以及少量低碳烷烃,CO2含量和总烃呈现反比关系;基性岩的CO2脱出量、脱出率高于中、酸性岩;CO2脱出量与岩石碱质含量正相关。松辽盆地北部昌德东CO2气藏成藏模式为“自生自储”,成藏CO2气主要来自深部被火山岩吸附的气。随岩浆上升,在岩浆冷凝成火山岩的过程中被吸附于火山岩的节理、劈理和晶体位错之中的CO2气,连同火山岩包体中的残留气,成为高纯CO2气藏的主要补给源,并非地幔气体沿大断裂上来直接充注成藏。