东地中海原型盆地演化

东地中海经历了伸展-聚敛的构造演化旋回,聚集了丰富的油气资源。基于2D地震、ODP Leg160、IHS及Tellus商业数据库和公开发表的文献资料,本文在建立东地中海及周缘构造-地层格架的基础上,恢复了东地中海12个关键地质历史时期的原型盆地,并以板块构造为切入点探讨了盆地演化机制。东地中海及周缘上三叠统以来地层可划分为新特提斯被动大陆边缘陆地及浅水区、新特提斯被动大陆边缘深水区和塞浦路斯弧前褶皱区3个地层分区,前两个地层分区均发育一套裂谷-被动大陆边缘层系,但是二者的岩相特征和不整合发育有明显的差异,而塞浦路斯弧前褶皱区发育一套大洋盆地-弧前盆地层系。研究认为东地中海经历了二叠纪—早侏罗世裂解期、中侏罗世巴柔期—晚白垩世土伦期漂移期和晚白垩世森诺期以来的汇聚改造期3个原型阶段,其中汇聚改造期又可细分为晚白垩世森诺期“双俯冲带”消减期、古近纪北部俯冲-碰撞期、中新世塞浦路斯岛弧带南侧俯冲-碰撞与黎凡特边缘活化期和中新世梅西期以来“弧-山碰撞”与“走滑逃逸”期4个阶段。东地中海盆地演化受控于图哈罗德-安纳托利亚板块以及凯里尼亚、特罗多斯和埃拉托色尼等微板块与冈瓦纳大陆北缘的分离、向北的漂移和与欧亚大陆汇聚拼贴的板块构造活动。     

新疆三塘湖盆地古生代晚期火山岩地球化学特征及其构造-岩浆演化意义

三塘湖盆地早石炭世安山岩（ECA）、早二叠世粗面岩类（EPT）以及中二叠世玄武岩（MPB）样品都具有大离子亲石元素（LILE）相对于高场强元素（HFSE）富集，Nb和Ta强烈亏损，轻稀土元素（LREE）相对于重稀土元素（HREE）富集，类似于和俯冲带相关的岩浆特征。ECA具有高的Zr／Nb（4．67～12．39），低的Nb／La（0．27～0．30），Ce／Ce＊=0．63～0．89，Sr／Sr＊=1．32．2．49，并具有Ti的负异常，另外（^87Sr／^86Sr）i=0．70408～0．70451，εNd（t）=＋7．42-＋7．88。与ECA相比，EPT大离子亲石元素更为富集，Ti和P的负异常明显，特别是Ce／Ce＊=0．72—1．64，Sr／Sr＊=0．38～1．87，相对较低的Al2O3和CaO含量以及（^87Sr／^86Sr）；=0．70414～0.70481和εNd（t）=＋4．93～＋6．13而区别于ECA。MPB与ECA相比具有较低的大离子亲石元素含量和较高的Nb、Ta含量，Ce／Ce＊=0．69～0．84，Sr／Sr＊=1、44～2．13，未有明显的Ti负异常，（^87St／^86Sr）i=0．70388～0．70396，εNd（t）=＋7．10-＋7．99。所有的地球化学特征表明：早石炭世或更早，三塘湖盆地为与俯冲带相关的构造背景，ECA是典型的弧火山岩，其岩浆主要源于被流体或沉积物交待改造的亏损地幔楔。早石炭世以后，三塘湖地区逐渐进入碰撞后伸展拉张阶段，EPT和MPB都为后造山火山岩。EPT岩浆主要源于亏损软流圈底侵前二叠纪形成的造山组分的部分熔融；MPB的岩浆主要源于亏损地幔的部分熔融，并被前二叠纪形成的造山组分或是年轻地壳混染。三塘湖地区二叠纪伸展拉张的动力学机制主要是由于造山带增厚的岩石圈大范围拆沉而导致的大范围亏损地幔部分熔融岩浆和上部造山组分或是年轻地壳的相互作用，这种造山组分或是年轻地壳具有低的（^87Sr／^86Sr），比值和正的εNd（t）值。火山岩地球化学特征指示没有明显地幔柱的作用特征。     

鄂尔多斯盆地二叠系烃源岩地球化学特征与沉积环境的关系

鄂尔多斯盆地二叠系烃源岩是盆地重要潜在的生烃岩系,以钻井岩心地球化学分析资料为主,对泥岩、泥质碳酸盐岩的微量元素、稀土元素和有机质地球化学特征进行了系统分析,其中微量元素含量与同类岩石的克拉克值相比,差别较大。轻稀土富集程度较高,重稀土相对较低,Ce/Ce*具有较明显的正异常,反映出烃源岩沉积环境总体为还原环境。研究认为,半深湖—深湖相带沉积的灰黑色泥岩类烃源岩还原程度强,有机质丰度高,有机质能被及时埋藏;河流—沼泽相沉积环境沉积的灰色—绿灰色泥岩类烃源岩有机质丰度较低。还原程度强、具一定深度水体的沉积相带是原始有机质沉积的良好场所,有机质能沉积并及时保存下来;而气候条件相对干燥、降水少、陆源碎屑物补充不足或较长时间处于氧化环境条件下沉积的泥质碳酸盐岩类岩石,有机质丰度明显偏差。     

Origin of the Eastern Mediterranean basin: a reevaluation

The origin of the Eastern Mediterranean basin (EMB) by rifting along its passive margins is reevaluated. Evidence from these margins shows that this basin formed before the Middle Jurassic; where the older history is known, formation by Triassic or even Permian rifting is indicated. Off Sicily, a deep Permian basin is recorded. In Mesozoic times, Adria was located next to the EMB and moved laterally along their common boundary, but there is no clear record of rifting or significant convergence. Farther east, the Tauride block, a fragment of Africa–Arabia, separated from this continent in the Triassic. After that the Tauride block and Adria were separate units that drifted independently. The EMB originated before Pangaea disintegrated. Two scenarios are thus possible. If the configuration of Pangaea remained the same throughout its life span until the opening of the central Atlantic Ocean (configuration A), then much of the EMB is best explained as a result of separation of Adria from Africa in the Permian, but this basin was modified by later rifting. The Levant margin formed when the Tauride block was detached, but space limitations require this block to have also extended farther east. Alternatively, the original configuration (A2) of Pangaea may have changed by 500 km of left-lateral slip along the Africa–North America boundary. This implies that Adria was not located next to Africa, and most of the EMB formed by separation of the Tauride block from Africa. Adria was placed next to the EMB during the transition from the Pangaea A2 to the Pangaea A configuration in the Triassic. Both scenarios raise some problems, but these are more severe for the first one. Better constraints on the history of Pangaea are thus required to decipher the formation of the Eastern Mediterranean basin.     

Organic geochemical characteristics and depositional environments of the Jurassic coals in the eastern Taurus of Southern Turkey

In this study, organic matter content, type and maturity as well as some petrographic and physical characteristics of the Jurassic coals exposed in the eastern Taurus were investigated and their depositional environments were interpreted.The total organic carbon (TOC) contents of coals in the Feke–Akkaya, Kozan–Gedikli and Kozan–Kizilinc areas are 24.54, 66.78 and 49.15%, respectively. The Feke–Akkaya and Kozan–Kizilinc coals have low Hydrogen Index (HI) values while the Kozan–Gedikli coals show moderate HI values. All coal samples display very low Oxygen Index (OI) values. The Kozan–Gedikli coals contain Type II organic matter (OM), the Feke–Akkaya coals contain a mixture of type II and type III OM; and the Kozan–Kizilinc coals are composed of Type III OM. Sterane distribution was calculated as C₂₇ > C₂₉ > C₂₈ from the m/z 217 mass chromatogram for all coal samples.T_max values for the Feke–Akkaya, Kozan–Gedikli and Kozan–Kizilinc coals are 439, 412 and 427 °C. Vitrinite reflectance values (%R_o) for the Feke–Akkaya and Kozan–Kizilinc coal samples were measured as 0.65 and 0.51 and these values reveal that the Feke–Akkaya and Kozan–Kizilinc coals are at subbituminous A or high volatile C bituminous coal stage. On the basis of biomarker maturity parameters, these coals have a low maturity.The pristane/phytane (Pr/Ph) ratios for the Feke–Akkaya, Kozan–Gedikli and Kozan–Kizilinc coals are 1.53, 1.13 and 1.25, respectively. In addition, all coals show a homohopane distribution which is dominated by low carbon numbers, and C₃₅ homohopane index is very low for all coal samples. All these features may indicate that these coals were deposited in a suboxic environment.The high sterane/hopane ratios with high concentrations of steranes, low Pr/Ph ratios and C₂₅/C₂₆ tricyclic ratios > 1 may indicate that these coals formed in a swamp environment were temporarily influenced by marine conditions.     

Organic geochemical characteristics of crude oils from the Masila Basin, eastern Yemen

The Masila Basin is an important hydrocarbon province in Yemen, but the origin of hydrocarbons and their generation history are not fully understood. In this regard, 10 crude oils from different petroleum reservoir sections in the Masila Basin were characterized by a variety of biomarker and non-biomarker parameters using GC, GC-MS and stable carbon isotope techniques. Oils from the Masila Basin display pristane/phytane (Pr/Ph) ratios ranging from 1.7 to 2.0, low sulfur content, high C₃₅ homohopane index, relatively high C₂₇ sterane concentrations and relatively high tricyclic terpanes suggesting a marine clay source rock that was deposited in mildly anoxic to suboxic conditions with dominantly algal organic matter. C₂₉ 20S/(20S + 20R) steranes and ββ/(ββ + αα) sterane ratios indicate that the Masila oils have reached peak oil window maturity. Another related feature of these oils is the absence of 18α (H)-oleanane, which suggests a source age older than Cretaceous. The carbon isotope compositions are similar to those of the potential source rocks, which range from −25.4‰ to −28.3‰, indicating a marine environment. The new data presented in this paper suggest that the Masila oils constitute one oil family and that the oil originated from the Upper Jurassic Madbi source rock in the basin.     

非洲Melut盆地北部不同地区原油有机地球化学特征及意义

为了明确Melut盆地北部不同地区原油母质来源、沉积环境及亲缘关系,采用饱和烃色谱及色谱-质谱方法,开展了盆地北部不同地区原油地球化学特征分析及对比。研究表明,盆地北部各地区原油正构烷烃无明显奇偶优势,Ts/Tm值1.36～3.47、C₃₁升藿烷22S/(22S+22R)比值0.54～0.60、αααC₂₉20S/(20S+20R)与C₂₉αββ/(ααα+αββ)比值大于0.4,总体表现为成熟原油;伽马蜡烷指数普遍小于0.1,C₂₁三环萜烷具有明显优势,Pr/Ph值0.97～2.31,均值1.61,指示其烃源岩形成于弱还原-弱氧化的淡水湖相环境;生油母质为II～III型混合型。不同地区原油母质来源及成熟度有差异：Moleeta次凹东坡原油为单峰后峰态分布,高碳数正构烷烃含量占优势,C₂₄TeT/C₂₃TT平均值大于1,具有明显的陆源高等植物贡献,原油成熟度较低,发育重质—中质油;Jamous次凹深洼区原油为前峰优势的双峰态分布,C₂₄     

羌塘盆地东部中生代沉积特征与构造演化

羌塘盆地东部基底由前石炭纪吉塘岩群组成,沉积盖层为晚古生代一白垩纪地层。其中,中生代海相地层在盆地内分布广泛,沉积体系多样,构造古地理转换频繁。中生代盆地包括南羌塘坳陷、唐古拉山隆起带、北羌塘坳陷等3个构造单元,内部又可以划分出不同时期多个次级凹陷和凸起。盆地的发展和演化既受南、北两侧板块结合带控制,又受盆地内部被分划性断裂带围限的各断块差异性活动约束,依次经历了晚三叠世前陆盆地阶段,“北羌塘”早-中侏罗世伸展裂陷盆地发育阶段,多玛侏罗纪-早白垩世早期被动大陆边缘陆表海盆地发展阶段、晚期前陆盆地阶段,晚白垩世南羌塘山间压陷盆地演化阶段。实质上,该盆地是不同时期原型盆地有序叠加而构成的大型叠复式盆地。     

松辽盆地白垩系青山口阶缺氧事件层的有机地球化学特征

松辽盆地白垩系青山口阶下部广泛分布一套富含有机碳的黑色泥岩、页岩沉积,它具有干酪根碳同位素正偏、重排甾烷含量低,普遍存在伽马蜡烷生物标志化合物等有机地球化学特征,代表了白垩纪温室效应时间窗内古湖泊贫氧环境条件下的沉积产物。结合生物地层研究成果,认为青山口阶下部曾发生过古湖泊缺氧事件,其层位大体可与白垩纪古海洋Cenomanian-Turonian界线事件层进行对比,由此提出了松辽盆地青山口阶下部的时代归属于晚白垩世Cenomanian晚期—Turonian早期的新观点。     

鄂尔多斯盆地西缘宁东地区侏罗系含铀地层元素地球化学特征

沉积岩的地球化学特征记录了岩石沉积时的重要地质信息,是研究沉积古环境、源区构造背景及源岩属性的有效手段。采用X衍射荧光光谱（XRF）和等离子体质谱仪（ICP-MS）对鄂尔多斯盆地西缘宁东地区中侏罗统直罗组下段地层砂岩和泥岩样品的主、微量元素及稀土元素含量进行测试分析,旨在对其沉积古环境进行恢复,并对其源区构造背景、源岩属性等特征进行综合研究。研究表明：Sr含量、Sr/Cu值、V/（V+Ni）值、U/Th值、化学蚀变指数（CIA）等地球化学指标综合指示出研究区直罗组下段地层沉积古气候为半干旱-半湿润气候,古水体环境为富氧的淡水环境。根据稀土元素（REE）特征分析,推测研究区直罗组下段地层物源主要来自盆地西北部的阿拉善古陆,源岩岩性主要为片麻岩、石榴石浅粒岩、变不等粒石英砂岩和变中细粒石英砂岩。源区构造背景主要为大陆岛弧,与大洋岛弧也有一定关联。     

Neotectonic aspects of the northern margin of the Adana-Cilicia submarine basin, NE Mediterranean

The sedimentary basins that dominate the north-eastern Mediterranean (Adana-Cilicia basins in the west and Iskenderun basin in the east) are located on the flanks of a partly submerged positive structure (a part of the Africa-Eurasia convergence zone) along which strike-slip faults are evident. This study summarizes the findings of two seismic surveys carried out in the Alanya-Mersin offshore region. Some 850 km of geophysical survey lines were compiled on these cruises. Based on the results determined from these surveys, the north and central part of Adana-Cilicia basin can be subdivided into eastern, central and western structural sub-basins separated by the Ecemiş fault complex in the east and the Anamur-Kormakiti structural high in the west at the same time. Results of this study also indicate that Ecemiş and Anamur-Kormakiti faults are active. Late Miocene regional compression was responsible for the compartmentation of this complex into the present arrangement and has initiated the rotational regime which has governed subsequent tectonic developments, notably the extensional behaviour of the NE-SW trending Ecemiş and Anamur-Kormakiti faults and the transpressive behaviour of the NNE-SSW trending border fault complex.     

Objective regionalization of Rayleigh wave dispersion data by clustering algorithms: an application to the Mediterranean basin

The main target of the present study is an objective and automated regionalization of Rayleigh wave dispersion data for the Mediterranean basin, without a priori seismotectonic constraints, and to determine the corresponding regional shear-velocity structures. The database used is formed by almost 200 Rayleigh wavetrains corresponding to 42 regional events, with surface-wave magnitude greater than 4.5, recorded at the MedNet very-broad-band stations in the Mediterranean area. Path-averaged group velocities for the Rayleigh wave fundamental mode are derived for each available epicentre-station trajectory crossing the Mediterranean basin. After this, a principal component analysis and a clustering process are applied to local group velocities, obtained for 13 different periods from 10 to 70 s, in order to classify the Mediterranean basin into several homogeneous regions. The stochastic inversion of the averaged group velocity dispersion curve obtained for each region provides the respective shear-velocity structures, down to a depth of 150–160 km. The characteristics of these areas and their possible correlation with the main seismotectonic features of the Mediterranean region are discussed. The regional models reveal significant lateral changes in the elastic structure, with the main differences concerning particularly the upper 35–40 km. Within this depth range, low shear velocities, varying from 2.8 to 3.9 km s⁻¹, characterize the Eastern Mediterranean, whereas higher velocities, ranging from 3.0 to 4.2 km s⁻¹, are deduced for the Western Mediterranean. These results suggest a thicker crust in the eastern part, but with a greater thickness of sedimentary layers. However, for depths of between 80 and 110 km, lower shear velocities are obtained in the Western part, while higher shear velocities are derived for the Eastern Mediterranean Sea, in the Aegean Sea, Greece, the south of Italy, Sicily and Tunisia. This velocity pattern suggests an averaged thicker lithosphere under the latter areas, as the top of the asthenosphere is detected at a mean depth of 75 km for the remaining regions. This thicker lithosphere can be related to processes associated with the convergence of the Eurasian and African plates and subduction under the Calabrian and Hellenic Arcs.     

PM10 and Pb evolution in an industrial area of the Mediterranean basin

The study area is highly industrialized, with businesses involved in the non-metal mineral products sector and ceramic industries (colors, frits and enamel manufacturing) standing out. Air quality evaluation was performed regarding atmospheric particles (PM10 fraction) and Pb in a Spanish coastal area during 2001 and 2002 in order to compare these values with other areas in the Mediterranean basin. Once the samples were collected, their PM10 fraction concentration levels were determined gravimetrically. A Pb analysis in air pollution filters was carried out by ICP-MS. The seasonal and weekly variabilities of these contaminants were also studied, with the objective of being able to explain their origin and thus minimize their possible damaging effects. A similar evolution of PM10 and Pb was observed in both years of the study. Higher PM10 concentrations have been detected during the months of June and July, lower values between March–May, August and October–December, and intermediate values in January and February. A similar tendency has been observed by other authors in European industrialized cities. Regarding Pb, the monthly mean remains constant during the entire year. In the study area, Pb represents 0.6% as a mean of the total PM10 mass, with a variation range between 0.1 and 5.1%. The major crystalline phases in PM10 were quartz, calcite, dolomite, illite, kaolinite and feldspars.     

赣杭构造带金衢盆地燕山期基性脉岩地球化学特征及成因探讨

赣杭构造带金衢盆地内发育有燕山期基性脉岩,岩石类型主要为辉绿(玢)岩.K-Ar年代学研究显示基性脉岩产出时代为69.5～131.7Ma,为白垩纪岩浆活动的产物.SiO2含量范围为46.70%～50.23%,K2O+Na2O为4.01%～7.82%,可分为碱性和亚碱性岩两类.微量元素相对富集大离子亲石元素(LILE)(K...     

安徽庐枞火山岩盆地橄榄玄粗岩系的地球化学特征及其对下扬子地区晚中生代岩石圈减薄机制的约束

庐枞盆地内的中生代火山-潜火山岩具高钾和相对富碱为特性,属典型的橄榄玄粗岩系列。它们在地球化学上表现出明显富集Rb、Th、U、K等强不相容元素和轻稀土元素,亏损高场强元素Nb和Ta的特征。Nd、Sr同位素组成总体位于富集型的扬子克拉通岩石圈地幔的范围内或其附近,显示其母岩浆主要是由富集型地幔部分熔融形成的。火山-潜火山岩的成分变异趋势显示橄榄玄粗质幔源岩浆在高压下(斜长石稳定压力之下,1.5GPa)经历过以单斜辉石和钛铁氧化物为主的矿物分离结晶作用。低压下矿物的分离结晶作用及上地壳物质的混染则不明显。这套火山-潜火山岩的部分地球化学性质(如Ce/Yb比值)类似于大洋岛弧内的橄榄玄粗岩,可能意味着区内由于岩石圈的减薄,软流圈地幔上涌到了岩石圈相对较浅的部位,控制源区部分熔融的主要是尖晶石相地幔岩。虽然局部(如靠近郯庐断裂的盆地西缘)可能存在着明显的热侵蚀,但突发性的机械拆沉是区内(乃至整个长江中下游地区)岩石圈减薄的主要机制。在整个晚中生代岩石圈减薄的过程中,这两种机制可能一直相互促进着。     

西藏林周盆地设兴组玄武岩地球化学特征及意义

青藏高原南部拉萨地块分布的晚白垩世岩浆活动,对了解特提斯洋的构造演化及约束印度-亚洲大陆初始碰撞时限等具有重要的意义。本文在西藏林周盆地林子宗火山岩的下伏晚白垩世设兴组地层中首次发现了玄武岩夹层,并系统开展了玄武岩的Ar-Ar年代学、全岩主量和微量元素地球化学、以及Sr-Nd-Pb同位素地球化学研究。设兴组玄武岩呈夹层状产出于设兴组顶部的红色砂岩中,其斜长石Ar-Ar年龄为90.6±1.8Ma。玄武岩属于高钾钙碱性系列,富集轻稀土元素、强烈富集Ba、Th、U等大离子亲石元素(LILEs),亏损Nb、Ta、Ti等高场强元素(HFSEs),具有明显的大陆边缘弧的火山岩成分特征。玄武岩的Sr-Nd-Pb同位素成分比较均匀,(87Sr/86Sr)t为0.706568~0.706620,εNd(t)为+0.72~+4.75,(206Pb/204Pb)t比值为18.649~18.675,(207Pb/204Pb)t比值为15.640~15.666,(208Pb/204Pb)t比值为39.055~39.108,岩石总体表现出来自于亏损地幔的特征。综合岩石学和地球化学研究结果,设兴组玄武岩可能是晚白垩世(约90.6Ma)俯冲于拉萨地块之下的新特提斯洋壳在重力拖拉下发生板片回转,导致软流圈物质上升提供热量,从而诱发了俯冲流体交代的地幔楔的部分熔融形成的。本文结果进一步证明,之前普遍认为缺少晚白垩世火山岩的拉萨地块南缘,存在新特提斯洋的俯冲作用及其岩浆作用产物。     

The Upper Pleistocene to Holocene sediments on the Mediterranean island of Lampedusa (Italy)

The island of Lampedusa lies on the northern edge of the African continental shelf, but during some Quaternary marine lowstands it was joined to the African continent. The study and dating of the aeolian, alluvial, detrital sediments, calcareous crusts and speleothems have established that the climatic–environmental variations recorded on the island can be related chronologically to those known for northern Libya, Tunisia and the Italian peninsula. During the Last Glacial Maximum, phases of Saharan dust accumulation on Lampedusa occurred, and were coeval with dust accumulation in crater lakes and on high mountains in central‐southern Italy, and with phases of glacial advance in the Apennines and in the Alps. During the late Holocene, accumulation of Saharan dust on Lampedusa occurred but there was little accumulation of dust on the northern side of the Mediterranean Sea. With the new data from Lampedusa, it is possible to envisage two different scenarios of atmospheric circulation relating to the Last Glacial Maximum and to the late Holocene. During the Last Glacial Maximum, southerly atmospheric circulation brought rainfall to the southern slopes of the Alps and to the Apennines. During the late Holocene, a prevalent westerly atmospheric circulation became established in the northern Mediterranean. Copyright © 2004 John Wiley & Sons, Ltd.     

四川盆地东部上三叠统须家河组层序-岩相古地理特征

提要: 以野外剖面、钻井岩心、测井资料、薄片鉴定和古生物特征分析为基础, 结合区域地质特征和前人研究成果, 对川东垫江地区须家河组沉积?层序特征进行了较为深入的研究和层序界面及洪泛面的识别, 结果表明: 须一段属于有障壁海岸沉积体系, 须二—须六段地层发育湖泊?辫状河三角洲沉积体系; 可将研究区内须家河组划分为于全盆地范围内可追踪对比的、分别相当“须下盆”和“须上盆”的2个构造层序及对应于须一至须六段的6个长期旋回层序(LSC1~LSC6); 以长期旋回层序界面和洪泛面为等时地层对比标志, 建立了川中隆起—川东南坳陷等时地层格架; 选择各长期旋回层序为等时地层单元编制层序?岩相古地理图, 解析须家河组各时期岩相古地理特征及相带展布规律。研究成果对指导川东地区须家河组油气勘探有重要意义。     

The geochemical evolution of the Catalan potash subbasin, South Pyrenean foreland basin (Spain)

Over the last decade, our studies in ancient evaporitic basins have been based on a detailed study of a single borehole record. The detailed findings in medium- to large-sized evaporitic basins were shadowed with a relevant question: can interpretations from a representative evaporitic record in a single borehole be extended to the whole evaporitic basin? This paper addresses that question; the results obtained are compared with results from another distant point within the basin. The general methodology not only proves its reliability in interpreting the evolution of evaporitic basins from a single borehole but reveals its capability to obtain detailed palaeoenvironmental interpretations.

The chemical evolution of an Upper Eocene evaporitic sequence from the South Pyrenean foreland basin (Spain) has been investigated along the Súria-19 borehole record. Detailed petrographic and mineralogical study, X-ray microanalysis of frozen primary inclusions trapped in halite (Cryo-SEM-EDS), systematic isotopic analysis (δ³⁴S and δ¹⁸O in sulphates) and computer-based evaporation models have been integrated in a multi-proxy methodology. This study revealed that a variable amount of Ca excess is required throughout different parts of the marine Lower Halite Unit (LHU) for sylvite, instead of K–Mg sulphates, to form. This Ca excess is in turn different from that required for the western sector of the same evaporitic basin (Navarrese subbasin). Quick and variable changes in Ca-rich brines or equivalent dolomitization required are explained as internal processes within the basin rather than secular variations in seawater chemistry.

The general hydrological evolution of the Catalan subbasin is explained as a restricted subbasin with a first marine stage in which continental input (up to 50% of total input) had an important control on the geochemistry of the subbasin. A second stage was determined during potash precipitation, in which the subbasin was cut from any seawater input to end up in its last stage as a purely continental evaporitic basin. Coupling evaporation models and analytical results we have obtained the proportions of recycling and their sources, estimated to change from a 100% (total mass of sulphate) Eocene source to 20% Eocene and 80% Triassic (Keuper) towards the latest stage of potash precipitation. The results obtained have been compared with results from the Navarrese subbasin allowing an integrated interpretation of the hydrological evolution of the whole Upper Eocene South Pyrenean basin. Local geochemical variations within the Upper Eocene south Pyrenean basin are explained by the differences in paleogeographical setting of the Navarrese and Catalan subbasins.     

山东莱芜盆地东部水文地质条件及富水块段特征

基于在莱芜盆地开展的1∶5万水文地质调查工作,详细论述了盆地东部地区水文地质条件,将区内地下水类型划分为松散岩类孔隙水、碳酸盐岩类裂隙岩溶水、碎屑岩类孔隙裂隙水与岩浆岩变质岩类裂隙水四类,并总结了其含水岩组富水性;分析了区内地下水补给、径流、排泄特征与地下水动态变化特征;通过收集分析区内钻孔资料,总结了岩溶区岩溶发育特征,发现区内岩溶发育主要集中在200 m以浅,以溶蚀裂隙、蜂窝状溶孔为主;对清泥沟断裂、兴隆山-高峪铺断裂、铜冶店-孙祖断裂等主要控水断裂进行分析,提出东泉、清泥沟、丈八丘三个岩溶水富水块段,分析了各块段的富水机理,并提出各富水块段允许开采地下水量,为地下水合理开发利用提供一定参考资料。