山东新泰野外露头发现下古生界含油碳酸盐岩

到目前为止,华北东部下古生界含油岩系研究主要依靠环渤海湾地区几个油田有限的钻孔资料(谯汉生等,2002),尚未获得大的突破。从2006年开始,在完成中国石油化工公司胜利油田有限公司委托的《胜利山东探区中深层天然气原型盆地构造演化研究》专题野外工作期间,笔者等在山东新泰市     

Genesis of fragmental carbonate rocks in the Mesozoic and Tertiary of Mallorca,Spain

Fragmental carbonate rocks are common in the Mesozoic and Tertiary succession of Mallorca, in the western Mediterranean. On the Formentor peninsula at the northeastern end of the Sierra Norte, two phases of fragmentation post-date Liassic platform carbonate and its subsequent reworking, and predate deposition of marine Burdigalian sediments. Phase 1 fragmentation resulted in brecciated rocks with angular fragments often little displaced, cemented by coarse calcite. Brecciated rock passes into veined or unbrecciated rock over short distances. These breccias are interpreted as the products of collapse during solution of an evaporite after uplift during the early Tertiary. Phase 2 fragmentation is related to the unconformity with Miocene sediments and is interpreted as a product of karstic processes operating prior to subsidence and deposition of Miocene marine conglomerates. Multiple brecciation is common, yielding complex fragmental rocks, but permitting a relative dating of the two phases and other depositional and structural events.     

中国海相碳酸盐岩评价中有关有机质丰度下限的几点讨论

综述了中国海相碳酸盐岩有机质下限研究的若干进展,认为针对不同需求,应提出碳酸盐岩烃源岩最低下限、有效烃源岩下限、战略选区下限3个不同的下限标准。高成熟碳酸盐岩原始有机质丰度恢复一直存在争议,根据生烃动力学,结合热史,可实现原始有机质总量的恢复。碳酸盐岩中泥质与有机质丰度、排烃能力是否相关仍存在争论,认为碳酸盐岩中泥质的作用仍有待进一步研究。     

中国海相碳酸盐岩评价中有关有机质丰度下限的几点讨论

综述了中国海相碳酸盐岩有机质下限研究的若干进展,认为针对不同需求,应提出碳酸盐岩烃源岩最低下限、有效烃源岩下限、战略选区下限3个不同的下限标准.高成熟碳酸盐岩原始有机质丰度恢复一直存在争议,根据生烃动力学,结合热史,可实现原始有机质总量的恢复.碳酸盐岩中泥质与有机质丰度、排烃能力是否相关仍存在争论,认为碳酸盐岩中泥质的作用仍有待进一步研究.     

四川盆地海相碳酸盐岩的油气成藏条件

四川盆地位于亚洲大陆中南部,是我国最大的外流盆地。油气资源评价结果(2008)表明,四川盆地海相地层待发现资源量约为50111.84×108m~3,资源勘探潜力巨大。本文从地层的划分、层序格架及层序岩相古地理特征等方面,对四川盆地海相碳酸盐岩油气成藏条件做了进一步研究。认为研究区烃源岩包括下志留统、中二叠统、上二叠统龙潭组和上三叠统须家河组等4套岩石,及局部发育的上二叠统大隆组。储集层粉为构造成因类和沉积成因类,构造成因主要包括裂缝性储层;沉积成因类储层主要是礁滩储层、内幕白云岩储层和风化壳岩溶储层。中二叠统气藏主要为自生自储的裂缝性气藏和台内滩相气藏;茅口组顶部和雷口坡组顶部发育风化壳型气藏;吴家坪组、长兴组及飞仙关组地层含礁滩型气藏;嘉陵江组和雷口坡组地层含内幕白云岩型气藏。     

海相碳酸盐岩烃源岩热解动力学研究:全岩和干酪根的对比

我国海相碳酸盐岩地层分布广泛,厚度巨大,经历的地质历史较长,特点是有机质丰度低,多处于高过成熟阶段.碳酸盐岩烃源岩评价对我国的油气资源评价与勘探至关重要.用生烃动力学方法来研究碳酸盐岩生油气过程是一个值得探索的研究方向.本文通过生烃动力学热模拟实验,求取了碳酸盐岩全岩和其干酪根不同烃类组分(甲烷、 C2～ C5气态烃)的生成动力学参数并进行对比.结果表明,在生烃动力学热解实验中,全岩和其干酪根具有相似的动力学参数,采用烃源岩应该比干酪根更符合实际,但是干酪根样品可以测得更为详细的实验数据,因此可以根据样品的情况,选择合理且易行的实验条件.在此基础上,以本文得到的参数作为参照指标,用动力学方法外推到地质实际中,可准确地提出适合我国的碳酸盐岩生烃定量模型,能为碳酸盐岩的资源评估等方面给出定量数值,从而为有效烃源岩的定量评价提供一种新的方法和途径.     

藏南岗巴地区上白垩统海相碳酸盐岩碳稳定同位素研究

本文对藏南岗巴地区上白垩统海相碳酸盐岩的碳稳定同位素组成特征及变化趋势进行了研究,对比分析了藏南其它地区及欧洲同时代地层,认为岗巴地层的碳稳定同位素的记录很好地响应了白垩纪期间全球性的缺氧事件。通过对岗巴地区岩石地层学及区域环境的分析说明,全球性的海平面升降及板块运动造成了大洋溶解氧含量的波动是碳稳定同位素δ¹³C值偏移的根本原因。     

Lithogeochemical patterns around Pb-Zn mineralizations in Dinantian carbonate rocks of (eastern) Belgium

The lithogeochemical distribution patterns of Mg, Sr, Na, Zn, Pb, Fe, Mn, K, Corg (organic matter) and IR (insoluble residue) in the Dinantian limestones and dolomites from the eastern part of Belgium have been studied (Dinant and Verviers synclinorium). Comparison of geochemical data of non-mineralized strata revealed higher background values in the strata of the Verviers synclinorium where Pb-Zn mineralizations occur. In this area a relation may exist with the metallogenetic district (Herve-Vesdre-Theux district; proposed by Dejonghe 1985b). However, the higher background values also could relate to the more restricted sedimentation conditions in the Verviers synclinorium as opposed to the more open marine conditions in the Dinant synclinorium. The influence of mineralization on the geochemistry of limestones is limited and unpredictable. In dolomites, however, the effect can be important. In these rocks, the lithogeochemical distribution of Zn, Pb and Mn can be subdivided into three populations, i.e. a regional background, a local high background and a halo population. The higher trace element concentrations in the halo population is caused by the existence of disseminated sulfide minerals (sphalerite, galena and pyrite) and Zn-bearing goethite (mainly pseudomorphs after pyrite) and Mn-oxides. The sulfides relate to the ore emplacement. In the local high background only the Zn-bearing oxides occur. Their presence and thus the development of the local high background relates to weathering processes.     

四川东部华蓥山三叠系海相碳酸盐岩对海水信息的保存性评估

海相碳酸盐成岩蚀变及其对海水信息保存程度的认识与评估在古海洋学和沉积地质学等学科领域研究中有着重要意义,尤其对于沉积地球化学和化学地层学等方面的研究是必不可少的基础工作。笔者通过对四川东部华蓥山仰天窝剖面三叠系海相碳酸盐岩样品的微观组构观察、阴极发光和微量元素等分析表明,大多数的样品保留了较好的原始沉积组构,具有极弱和弱的阴极发光强度、较低的Mn含量和较高的Sr含量,同时也具有较小的Mn/Sr值。只有6个样品被认为遭受了较大的成岩蚀变而对海水信息的保存程度较差,需要被剔除,而大多数的样品只遭受了较小的成岩蚀变作用,较好地保留了当时海水的信息,仍然在很大程度上代表了当时的海水。     

Unusual N—Alkane Distributions in Extracts from Marine Carbonate Rocks at High Levels of Maturity and Overmaturity

N-alkanes in extracts from possible carbonate source rocks of the Lower Ordovician Majiagou Formation in the central gas field of the Shanganning Basin and the Upper Sinian Dengying Formation in the Weiyuan gas field of the Sichuan Basin, are characterized by bimodal distributions with the dominant carbon numbers in the range C₁₇-C₂₁ and C₂₅-C₂₉. In most samples, the lower carbon number components are present in greater abundance than the higher carbon number ones. Most samples contain significant concentrations of waxy hydrocarbons (C₂₂₊) with C_21-/C₂₂₊ ratios between 0.50 to 3. 16, and an average value of 1. 34. The n-alkanes in extracts of outcrops and shallow core samples of Upper Proterozoic and Lower Palaeozoic carbonate rocks in the western and southern parts of the North China Basin are of unimodal distributions dominated by n-alkanes maximizing in the C₂₅-C₂₉ range. These extracts have very high concentrations of waxy hydrocarbons with C_21-/C₂₂₊ ratios all < 1. 0, ranging from 0. 14 to 0. 90 and averaging 0. 36. All of the extracts have a marked odd/even predominance in the high molecular weight n-alkane range regardless of whether they are from shallow or deep cores or out-crop samples. Simulation experiments were performed using typical sapropelic-type kerogens from the immature Sinian Lower Xiamalin Formation carbonate-rich shales collected at Jixian, Hebei Province, North China Basin, and the contemporary microplanktonic blue-green algaeSpirulina subsala. Results indicate that the unusual distribution of n-alkanes in the extracts of Upper Proterozoic and Lower Palaeozoic carbonate rocks possibly originated from algae in the source rocks at high levels of maturity and overmaturity. This research project was financially supported by the Chinese Academy of Sciences (Grant No. KZCX2-111 ).     

Resedimented carbonate and volcanic rocks in the Berriasian-Hauterivian of the Subbetic (Alamedilla, Betic Cordillera, southern Spain)

Sedimentary rocks of the Lower Cretaceous in the Subbetic of the Alamedilla area (province of Granada) were studied. In this area, a significant amount of redeposited sediments within the Carretero Formation were recorded. Resedimented material is mainly composed of Jurassic oolitic limestones and volcanic rocks, as well as of Neocomian hemipelagic sedimentary rocks (marly limestones and marls). All these redeposited sediments corresponding to rock fall and debris flow originated as the result of significant slopes in a very sharp submarine topography. Volcanism and the resultant volcanic edifices created this sharp slopes making up in some cases guyots. The volcanism was mainly active in the Middle Jurassic, although it persisted locally until Late Jurassic and Early Cretaceous, and controlled the sedimentation in this area of the Subbetic basin during most of the Mesozoic. The proposed genetic model is in agreement with a base-of-slope apron model with two significant special features: (1) the provenance of the clasts mainly from Jurassic outcrops with oolites deposited in guyots and isolated marine platforms, and volcanic submarine rocks, and (2) the palaeobathymetry of the deposits, relatively shallow and sporadically affected by storm waves.     

Tepee structures and associated diagenetic features in intertidal carbonate sands (lower Jurassic,Morocco)

In southeastern Morocco, Early Jurassic inter- to supratidal carbonates can be followed for 200–300 km along the southern slopes of the High Atlas mountains. These beds form intervals of several tens to more than one hundred metres.Tepee structures, which are common in these beds, are confined to coarse-grained, early lithified beaches. Comparison with similar features in the Recent, and analysis of the diagenetic history of the sheetcrack-fills suggests that the formation of the tepees is an early, almost synsedimentary event.     

Movement of contaminants in karstified carbonate rocks

Dynamic flow systems and transport of contaminants in karstic aquifers result from the actions of physical and chemical processes involving aqueous systems containing certain contaminants. These processes are elaborated, and pertinent mathematical and chemical equations are discussed, herein. Contaminant transport in karstic aquifers can be mathematically expressed by the basic equations evaluated primarily for the flow in porous, highly permeable aquifers. The effects of advection, hydrodynamic dispersion, and dilution are elaborated as physical processes that effect the movement of contaminants through groundwater in permeable rocks. Physical and chemical mechanisms that govem contaminant movement and groundwater flow through fractured media are proposed as the basis of an approximate scenario of contaminant transport through karstified carbonate rocks.     

苏皖地区石炭纪海相碳酸盐岩碳和氧同位素演化规律

对江苏南京孔山和安徽巢湖凤凰山石炭系碳酸盐岩C、O稳定同位素进行了测定。结果表明，苏皖地区石炭系δ^13C,δ^18O记录是以4个同位素演化阶段为特征，前3个同位素演化阶段与同时代的北美石炭纪相似，仅仅是内部演化特征略有不同，这反映了区域性的沉积环境的不同变化。在金陵组下部、和州组下部、黄龙组中下部和船山组层段，δ^13C表现出明显的正漂移，这可能是受植物和生物量增长、有机碳储藏量增加所引起的。δ^18O记录总体上与δ^13C值呈相似的变化趋势。δ^18O增加记录了气候变冷和冰川作用的结果。δ^18O负漂移与气候变暖和冰川消融是一致的。在浅水潮坪环境，大气淡水的淋滤作用使δ^13C和δ^18O值明显降低。     

西藏措勤地区发现第三纪富钾岩浆岩

西藏措勤地区发现了第三纪富钾火山岩及正长岩,其同位素年龄分别为15.8～15.9Ma和27.15Ma。火山岩主要岩石类型为粗安岩,少量粗面岩、玄武粗安岩、白榴石玄武粗安岩;正长岩主要岩性为中—中粗粒或似斑状霓辉正长岩。岩石学、岩石化学初步研究表明其属于钾玄质-超钾质火山岩和碱性正长岩。这一发现填补了冈底斯北部新生代富钾质岩浆活动的空白,为进一步研究青藏高原形成和演化提供了重要资料。     

Magnetostratigraphy of Tertiary Rocks from Maoming Basin,Guangdong Province,China

The Maoming Basin is one amongst a group of Cretaceous-Tertiary basins in South China-347 samples were collected from drill cores MR and MB and section MS (110° 54′ E. 21° 45′ N). Most of the lithological units are of Tertiary age. The cores include the Laohuling. Shangcun, Huangniuling and Youganwo formations. The MR core (874m in length) has recorded the polarity history from Normal Zone 18 to Normal Zone 11 on the Geomagnetic Polarity Time Scale (GPTS). The strata were formed from about 42Ma to 32Ma, that is from Late Eocene to Early Oligocene. A mean sedimentation rate of this stratigraphic column is 8.1 cm/ka.     

Sr isotope chemostratigraphy of Upper Jurassic carbonate rocks in the Demerdzhi Plateau (Crimean Mountains)

The first Sr chemostratigraphic data are obtained for the Upper Jurassic carbonate sections in the Demerdzhi Plateau of the Crimean Mountains. The oncoid, microbial, and organogenic-detrital limestone varieties representing shallow-water marine microfacies of the carbonate platform served as material for these studies. The limestone samples for reconstructing the isotopic parameters of depositional environments were selected using geochemical criteria (Mn/Sr < 0.2, Fe/Sr < 1.6, Mg/Ca < 0.024) and subjected to the preliminary treatment in a 1 N ammonium acetate solution. The ⁸⁷Sr/⁸⁶Sr value in the least altered samples increases up the section from 0.70701 to 0.70710. The obtained ⁸⁷Sr/⁸⁶Sr values are correlated with the Sr isotope properties of belemnite rostrae characterizing the Pectinatites scitulus-Pavlovia rotunda ammonite zone in the zonal scale of the Boreal realm, Hyponoticeras hybonotum-M. ponti/B. peroni Zone in the zonal scale of the Tethyan realm, and lower part of the Dorsoplanites panderi Zone in the zonal scale for the transitional domain of the East European Platform. The Sr chemostratigraphic correlation indicates the early Tithonian age of sediments developed in the eastern part of the Demerdzhi Plateau and restricts the upper boundary of the limestone section redeposited within carbonate breccia of Mount Severnaya Demerdzhi to the terminal early Tithonian. The Sr isotope data are used for calculating the sedimentation rates for limestones. They are estimated to be at least 0.23 m/1000 years, which is an anomalously high value for pre-Quaternary carbonate platforms.