Vitrinite reflectance and consolidation characteristics of the post‐middle Miocene Forearc Basin in central and eastern Boso Peninsula,central Japan: Implications for basin subsidence

To understand the sedimentary development of the Boso Forearc Basin, central Japan, since ~ 3 Ma, we investigated paleothermal structure and consolidation trends in the central and eastern parts of the forearc basin through vitrinite reflectance measurements and consolidation tests. Vitrinite reflectance (R_m) was in the range 0.33 % to 0.61 % for the Miura Group in the central part of the forearc basin and 0.34 % to 0.41 % for the Miura and Kazusa Groups in the eastern. These values suggest a roughly uniform vitrinite reflectance for the Miura Group from the central to eastern parts. No significant vitrinite reflectance difference is observed across the ~ 3 Ma Kurotaki Unconformity in the eastern part of the basin. The consolidation yield stress (p_c) was calculated as 27.5 MPa and 32.2 MPa for the Kiyosumi and Amatsu Formations of the Miura Group in the eastern part, respectively. Both the p_c values are consistent quantitatively with represent the trend of the maximum overburden pressure estimated from the thickness and density of overlying sediments, and the difference in p_c is expected by the maximum burial depths of the strata at the sampling localities. Values of p_c in the eastern part of the basin increase with thickness of overlying sediment, showing no break across the Kurotaki Unconformity. Considering the eroded thickness of the Miura Group, the continuous trends in vitrinite reflectance and consolidation between the Miura and Kazusa Groups in the eastern part reflect the greater deposition of the eastern part of the Boso Forearc Basin since ~ 2.3 Ma.     

塔里木盆地顺托果勒低隆及邻区加里东中期运动面的构造性质

顺托果勒低隆及邻区加里东中期运动面的结构特征、区域分布规律及其构造性质具有重要的研究意义。本文运用钻井资料分析、地震资料解释等对研究区加里东中期运动面进行研究,结果表明：1）研究区加里东中期3个幕次的构造运动导致3个运动面的形成：Ⅰ幕运动面由塔中地区的O3l/前O3l角度不整合面、顺托果勒到塔北地区的O3q/O2yj平行不整合面组成,Ⅱ幕运动面为O3s （或O3qr）与下伏碳酸盐岩构成的同构造沉积超覆型角度不整合面,Ⅲ幕运动面为S/O角度不整合面,在隆起区存在显著的构造削截特征。2）3个运动面的结构特征和差异分布规律具有明确的构造指示意义：Ⅰ幕、Ⅲ幕运动面属于典型的构造成因不整合面,形成于周缘洋盆关闭、陆块碰撞造山时期;Ⅱ幕运动面的形成则受到早期构造格局、全球海平面上升及盆地南缘碰撞造山作用的综合控制。3）顺北、顺南地区地震剖面中存在沿鹰四段顶面以下顺层规律分布的“串珠”反射,推测属于准同生岩溶洞穴。     

松辽盆地北部姚家组底部不整合面的发育特征及形成机制初探

松辽盆地北部姚家组底部的不整合面（T_1-1界面）为区域性不整合面,这一不整合面标志的隆升事件不仅控制了地层分布和层序划分,而且把盆地的坳陷阶段分为湖侵特征各不相同的两个亚阶段.姚一段的剥蚀区主要见于松辽盆地的东部和北部,反映造成这一隆升的挤压应力场来自其东南,与东亚大陆边缘移置地体的拼贴有关.松辽盆地是一个与燕山造山作用耦合发育的内陆盆地,坳陷（裂后热沉降）阶段的盆地发育受制于两个造山作用：西侧大兴安岭的热隆升和其东的东亚大陆边缘的地体拼贴引起的斜向汇聚-剪切造山作用.     

输导体系研究进展

通过输导体系的分类,输导体系研究的特点等分析,详细介绍了目前输导体系的研究现状。把输导体系研究分为静态和动态两种,从静态研究角度将输导体系细分为储集体输导体系、断裂输导体系、不整合面输导体系和复合型输导体系四种,指出输导体系具有独立性、动态性、两面性、复杂性和综合性的特点。从动静结合的角度对目前输导体系的层序地层、沉积、成岩、盆地模拟、成藏动力学、地球化学、地球物理实验模拟、地质建模等多种研究方法及其优缺点进行了详细介绍。在此基础上指出了目前输导体系研究中存在的问题和输导体系研究的发展趋势。     

Regional geology and petroleum systems of the Illizi–Berkine area of the Algerian Saharan Platform: An overview

The Berkine and Illizi basins are Palaeozoic–Mesozoic intraplate depressions that preserve an over 7000 m thick sedimentary rock record and contain world-class petroleum systems with over 39 BBOE EUR hydrocarbon reserves. Regional seismic transects and a wealth of well data are used to review the tectonostratigraphic evolution of the area. The Gondwana (Palaeozoic) and Tethys (Mesozoic) supercycles make up the bulk of the Phanerozoic succession. These 1st order cycles record extensional basin formation, followed by a protracted period of overall net subsidence, and conclude with basin inversion and regional uplift during the Hercynian and Alpine orogenies respectively. Structural styles were dictated by transpressional or transtensional reactivation of mostly NNE oriented basement structural grain of Late Proterozoic–Ea.Cambrian (Pan-African) age and vertical movement of long wavelength regional highs and lows. Local tectonism is considered to be the far-field effect of plate-tectonic processes that affected the North African plate-boundaries, such as the Caledonian and Hercynian Orogenies, the opening of the Tethys and Atlantic oceans, and the Alpine Orogeny. These were accompanied by localised thermal mantle processes.     

Stratigraphy and palaeoenvironmental evolution of the mid- to upper Palaeozoic succession in Northwest Peninsular Malaysia

The stratigraphy of the Devonian to Permian succession in Northwest Peninsular Malaysia is revised. The Timah Tasoh Formation consists of black mudstone containing graptolites and tentaculitids indicating a Pragian or earliest Emsian age. The Sanai Limestone overlies the Timah Tasoh Formation at Sanai Hill B and contains conodonts indicating a Late Devonian (Frasnian to possibly early Famennian) age. In other places, Late Tournaisian chert of the Telaga Jatoh Formation overlies the Timah Tasoh Formation. The overlying Kubang Pasu Formation is predominantly composed of mudstone and sandstone, and can be divided into 3 subunits, from oldest to youngest: (1) Chepor Member; (2) Undifferentiated Kubang Pasu Formation; (3) Uppermost Kubang Pasu Formation. The ammonoid Praedaraelites tuntungensis sp. nov. is reported and described from the Chepor Member of Bukit Tuntung, Pauh. The genus indicates a Late Viséan age for part of the subunit. Dropstones and diamictites from the Chepor Member indicate a glacial marine depositional environment. The Carbo-Permian, undifferentiated Kubang Pasu Formation consists of similar interbedded mudstone and sandstone. The uppermost Kubang Pasu Formation of Kungurian age consists of coarsening upward cycles of clastics, representing a shallow marine, wave- and storm-influenced shoreline. The Permian Chuping Limestone also represents shallow marine, wave- and storm-influenced deposits. A Mid-Palaeozoic Unconformity separating Early–Late Devonian rocks from overlying Late Devonian–Carboniferous deposits probably marks initiation of rifting on Sibumasu, which eventually led to the separation of Sibumasu from Australian Gondwana during the late Sakmarian (Early Permian).     

富宁阳文冲金矿成矿地质背景及矿体分布特征

金矿赋存于旧腮背斜西翼上寒武统唐家坝组（∈3t）碳酸盐岩与下泥盆统坡脚组（D1P）细碎屑岩不整合面之上的坡脚组地层的断层破碎带中。     

A detailed fluid inclusion study in silicified breccias from the Kombolgie sandstones (Northern Territory, Australia): inferences for the genesis of middle-Proterozoic unconformity-type uranium deposits

The relative chronology and detailed chemistry of paleofluids circulating at the base of the Kombolgie Sub-basin were investigated in the East Alligator River district (Northern Territory, Australia), where world-class unconformity-type uranium deposits are located. The chemistry of fluid inclusions was determined using in-situ analysis (Raman microprobe and laser-induced breakdown spectroscopy [LIBS]) and by observing the melting sequences by microthermometry. This study revealed the occurrence of three distinct fluids: (i) a sodium-rich brine that corresponds to a diagenetic fluid percolating at the bottom of the Kombolgie sandstones at a temperature close to 150±15 °C; (ii) a calcium-rich brine, probably corresponding to a residual brine in evaporitic environment that has evolved by fluid–rock interactions with the basement lithologies; and (iii) a low salinity fluid, heated in the basement, injected into the base of the sandstone cover. H₂ and O₂ and/or traces of CH₄ were detected in the vapor phase of some fluid inclusions, especially in the low salinity ones in quartz breccia samples taken above mineralized areas. Hydraulic brecciation of the sandstone was associated with a pressure decrease favoring fluid mixing and the subsequent cementation of breccias. According to the fluid inclusion study and other geologic constrains, the minimum thickness of the Sub-Kombolgie Basin is estimated at 4 km. Drusy quartz breccias with evidence of fluid mixing are quite common at the base of the Kombolgie Basin, but not necessarily linked to U-mineralization. However, it is proposed that the presence of gases such as H₂ and O₂ in fluid inclusions, which results from water radiolysis, constitutes an indicator of gas linked to significant U concentrations deeper in the basement rocks.     

江西朱溪钨铜矿找矿进展及建议

江西朱溪铜矿是一个正在开采的小型矿山,近年来,通过对朱溪外围铜钨多金属矿的勘查与研究,地质找矿取得重大突破,综合研究也取得了重大进展。在此基础上,综合矿区最新工作成果,从不整合面控矿构造、隐伏成矿岩体、矿化蚀变特征等几方面,分析了朱溪地区铜多金属矿的成矿规律,提出塔前—朱溪—赋春、东乡枫林—弋阳曹溪—德兴福泉山、永平—陈坊3个中生代断陷盆地是区域展开的新思路。