中上扬子区奉节-观音垱剖面深部温度场及热结构特征

在大地热流密度分布的基础上,本文基于二维稳态热传导方程,根据研究区热导率、生热率等热物理性质参数,对横穿川东北地区、秭归盆地、黄陵穹窿和江汉盆地等几个构造单元的奉节（FJ）-观音垱（GYD）地学剖面进行了温度场数值模拟研究,获得了其深部热结构认识。模拟结果显示,地幔热流自西向东逐渐升高,变化范围约为25.3～34.7 mW/m²。莫霍面温度大约在380 ℃～450 ℃之间变化。热岩石圈厚度自西向东先稍微增厚,后逐渐变薄,变化范围约为115～171 km。江汉盆地中新生代的伸展作用使其地幔热流稍有升高,“热”岩石圈厚度相对较薄（约116 km）,而川东北地区则受到早期的挤压和晚期的抬升剥蚀作用,地幔热流相对较低,其深部“热”岩石圈厚度也相对较厚（约168 km）。     

中国满州里—绥芬河地学断面放射性元素与岩石圈热结构及温度分布

根据断面域兴安、松嫩地块各时代地层和花岗质岩石及所估算的地壳各结构层的Ｋ、Ｕ、Ｔｈ含量，研究了岩石的热产生率及其变化、以及岩石圈的热结构和温度分布，揭示了兴安、松嫩地块热产生率与岩性及时代的关系。兴安、松嫩地块均以高热流为特征，特别是松嫩地块为明显的高热异常区。岩石圈内的温度分布结合地球物理信息的分析表明，两地块深部地壳可能存在低速高导的部分熔融体。     

青藏高原亚东-格尔木地学断面

据大量的地质资料和地球物理数据,对青藏高原划分了6个地体,虽然该区地壳是分块的,但该区仍是一个独立完整的岩石圈构造单元;若从安多分界,南北地壳结构、构造不同。南部构造复杂,北部简单。经研究本区地壳的缩短与加厚,主要与板片俯冲和逆冲、叠覆等8种因素有关。本区隆升的力学机制,可能是以印度板块向北挤压力为主,同时受到欧亚板块向南挤压力。这种双向挤压力,导致软流圈运动,同时还受到核幔边界突起热的影响。     

渤海盆地现今岩石圈热结构及新生代构造-热演化史

依据236口井共2 706组的静温数据以及25口井的系统测温数据,分析计算了渤海盆地地温梯度及大地热流;建立地壳分层结构模型,利用回剥法计算现今地幔热流、深部温度以及岩石圈厚度;在此基础上,利用地球动力学方法恢复本区热流演化史。结果表明：渤海盆地背景地温梯度为322 ℃/km,热流值为648 mW/m2;盆地现今热岩石圈厚度在61~69 km之间,地幔热流占地表热流的比例在60%左右,属于“热幔冷壳”型岩石圈热结构,盆地地壳底部或莫霍面温度变动在548~749 ℃之间;热流演化的特征与盆地的构造演化背景吻合,新生代以来盆地经历了3期岩石圈减薄并加热的过程,在东营组沉积末期热流达到最高(70~83 mW/m2）,这期间盆地内产出多期碱性玄武岩,表明盆地经历了波及地幔的裂谷过程,随后进入热沉降期,热流逐渐降低,盆地向坳陷型转变。     

四川阿坝——秀山地学断面

四川省阿坝—秀山地学断面长约1000km,横跨上扬子地台和松潘-甘孜地槽褶皱系。在综合研究现有地质、地球物理资料的基础上,对断面及邻区划分出不同性质的三大岩石圈块体;结合表壳变形特征又区分出以四川地块为中心的东、西对冲构造体系;并进一步划分出8个次级构造带(块)。在垂向上划分出地壳、岩石圈厚度及形态,讨论了地壳次级分层及壳、幔低速层、低阻层和高阻层异常的特征,提出了初步解释。指出龙门山断裂带西部地壳缩短、增厚的主要因素。概述了地壳演化。     

塔里木盆地岩石圈热-流变学结构和新生代热体制

塔里木盆地是我国特大型沉积盆地,也是“西气东输”工程的重要战略基地。利用盆地区大量的地温及岩石热物性参数并结合地热学知识分析了塔里木盆地的现代地温场、热演化和岩石圈热-流变学结构,并进一步讨论了地热场和岩石圈性质对成盆、成烃和成藏的意义。研究结果表明塔里木盆地现今平均大地热流为45mW/m2,平均地温梯度为18~20℃/km;整体上具有低温冷盆的特征。地温场的展布具有明显的横向差异,不同构造单元的地温场特征相差较大:坳陷部位具有较低的地温,隆起区具有较高的地热特征。热演化模拟表明盆地自成盆以来经历了从震旦纪—奥陶纪高热流(“热”盆)、志留纪—晚古生代热衰减(“热”盆向“冷”盆过渡)、中生代稳定的热演化(低热流“冷”盆阶段)、新生代岩石圈挠曲热演化等阶段。“热”岩石圈厚度为205~230km,有效弹性厚度(Te)达66±7km,脆-韧性转换深度为25~28km,岩石圈总强度为1.6×1013~7.8×1013N/m。盆地区的岩石圈表现为地温低、强度高的刚性块体,具有整体变形特征。受印度-欧亚大陆碰撞的远程效应影响,塔里木盆地作为刚性块体进行应力传递,盆地周边产生强烈变形,表现山脉的急剧隆升和盆地边缘的快速挠曲沉降。这一动力学过程造成地层内部流体趋于流向山前隆起带,并对油气成藏和分布具有重要的控制作用。     

黑水-泉州地学断面四川盆地区段的地壳热结构模型及热演化史

在讨论黑水─泉州地学断面四川盆地区段地壳结构基本特征的基础上，采用一维稳态热传导方程计算了该区段内14个点的不同构造层段的古地温和古热流值，建立了地壳然结构模型，并对沉积盖层的热演化史进行了探讨。结果表明，四川盆地在晚三叠世末到晚侏罗世末这一时期是热演化程度最高的时期，且在晚侏罗世末期已趋于热均衡状态。各地区各构造层段具有不同的热结构特征和热演化史，它总体上受控于岩石圈厚度及莫霍面的理深，局部受控于各构造层的厚度、物性特征及岩浆活动等因素。     

青藏高原东缘深部电性结构特征研究

通过对青藏高原东缘大地电磁测深实测资料的分析,结合区域地质、重、磁、大地电磁和地震资料,文章对青藏高 原东缘的深部构造、壳内高导层、电性结构与矿产的关系进行了研究。结果表明,重力计算中的莫霍面是由诸多高低变化 电阻组成的一个界面,莫霍面之上容易形成壳内高导体;在20 km深度左右存在电阻率变化界面,为上下地壳界面的反映。 电性和Vs研究表明,在地幔柱发育地区,地壳厚度减薄了15 km左右。区内诸如金沙江-红河断裂、鲜水河断裂等深大断裂 带已经深达莫霍面,成为各块体或成矿带的边界,控制了岩体和壳内高导体的分布。进而探讨了贡嘎山壳幔高导体的成因 以及区内地幔柱与矿产的关系。     

华南地区进贤-柘荣剖面深部电性结构

为了研究华南地区的深部电性结构,探寻浅部地质过程的深部背景,布设了江西进贤至福建柘荣超长周期大地电磁测深剖面。通过剖面数据的处理、定性分析及二维反演,获得剖面岩石圈尺度的电性结构模型,并分区块对壳幔电性结构及主要断裂进行了分析。反演结果表明：1）剖面可分为4个构造单元,分别为江南造山带、华夏地块内部、华夏褶皱带和东南沿海岩浆岩带;2）武夷山与东南沿海岩浆岩带两处电性莫霍面隆起,电性莫霍面的起伏特征受控于区域深大断裂;3）剖面电性岩石圈整体表现为西薄东厚,江南造山带岩石圈-软流圈界面埋深为80~100 km,华夏褶皱带及东南沿海岩浆岩带的岩石圈-软流圈界面埋深约为140 km,存在一处岩石圈减薄区和两处软流圈上涌区,反映了伸展构造作用对岩石圈的不均匀改造。     

中国大陆地区沉积盆地热状况剖面

根据我国沉积盆地大量实测的地温、大地热流资料和岩石热物理性质数据,分析、总结了由东至西我国主要沉积盆地的现今地温、大地热流、深部地热及岩石圈热结构的分布状况及其差异,为我国的地热研究的进一步深入提供了可靠的基础资料。     

Heat flow and lithospheric thermal regime in the Northeast German Basin

New values of surface heat flow are reported for 13 deep borehole locations in the Northeast German Basin (NEGB) ranging from 68 to 91 mW m^− 2 with a mean of 77 ± 3 mW m^− 2. The values are derived from continuous temperature logs, measured thermal conductivity, and log-derived radiogenic heat production. The heat-flow values are supposed free of effects from surface palaeoclimatic temperature variations, from regional as well as local fluid flow and from thermal refraction in the vicinity of salt structures and thus represent unperturbed crustal heat flow. Two-D numerical lithospheric thermal models are developed for a 500 km section along the DEKORP-BASIN 9601 deep seismic line across the basin with a north-eastward extension across the Tornquist Zone. A detailed conceptual model of crustal structure and composition, thermal conductivity, and heat production distribution is developed. Different boundary conditions for the thickness of thermal lithosphere were used to fit surface heat flow. The best fit is achieved with a thickness of thermal lithosphere of about 75 km beneath the NEGB. This estimate is corroborated by seismological studies and somewhat less than typical for stabilized Phanerozoic lithosphere. Modelled Moho temperatures in the basin are about 800 °C; heat flow from the mantle is about 35 to 40 mW m^− 2. In the southernmost part of the section, beneath the Harz Mountains, higher Moho temperatures up to 900 to 1000 °C are shown. While the relatively high level of surface heat flow in the NEGB obviously is of longer wave length and related to lithosphere thickness, changes in crustal structure and composition are responsible for short-wave-length anomalies.     

Meso‐Cenozoic thermal structure of the lithosphere in the Bohai Bay Basin,eastern North China Craton

Thermal structure of the lithosphere studies the partition of crustal and mantle heat flow of the continental area and is of significant importance to understand various energy‐related geodynamic processes. The study addresses the spatial distribution of the Meso‐Cenozoic mantle heat flow and Moho temperatures in the region of the Bohai Bay Basin based on the thermal history of the sedimentary basin, radioactive heat production rate and thickness of crustal layering. The results show that the ratio of the mantle and surface heat flow (q_m/q_s) experienced two peaks in the late period of the Early Cretaceous (q_m/q_s ~ 68%) and the Middle to Late Palaeogene (q_m/q_s ~ 75%), respectively. Based on the q_m/q_s ratio, the lithosphere of the Bohai Bay Basin transformed its thermal structure during the Meso‐Cenozoic, from the ‘cold mantle but hot crust’ stage in the Triassic–Jurassic to the ‘hot mantle but cold crust’ stage in the Cretaceous and Cenozoic. The Moho temperatures (T_m) during the Meso‐Cenozoic were also calculated by using the equation of one‐dimensional heat conduction, and the result shows that there exist three T_m peaks occurring in the late period of the Early Cretaceous (930–1080 °C), the Middle‐Late Palaeogene (820–890 °C) and the Early Neogene (770–810 °C). The q_m/q_s ratio began to exceed 50%, and the Moho temperature started to go over 700 °C from the Cretaceous to the present day, which revealed that the activity of the upper mantle in the eastern North China Craton (NCC) increased significantly accompanied by the strong crustal movement in the Cretaceous. The thermal structure revealed the Cretaceous to be a revolutionary period during the evolution of the Bohai Bay Basin, and this paper may provide some thermal evidence for the studies of the geodynamic evolution during the destruction of the NCC. Copyright © 2015 John Wiley & Sons, Ltd.     

青藏高原东缘地壳上地幔结构及其动力学意义

本文综述了我们在青藏高原东缘实施的垂直切过龙门山断裂带宽频带地震探测的研究成果,揭示了研究区复杂的地壳上地幔结构,结果表明松潘-甘孜地块与四川盆地西缘莫霍面深度为58 km与40 km±,在龙门山断裂带下方存在约15 km的莫霍面错断; 松潘-甘孜与龙门山断裂带域地壳纵横波速度比Vp/Vs比值远大于173,预示着粘性下地壳流或基性/超基性物质的存在。探讨了研究区强烈的盆山之间以及深部不同层圈之间的相互作用,推断四川盆地对青藏高原东缘软流圈驱动的物质东向逃逸阻挡作用可能深达整个上地幔。     

Heat flow and thermal modeling of the Yinggehai Basin, South China Sea

Geothermal gradients are estimated to vary from 31 to 43 °C/km in the Yinggehai Basin based on 99 temperature data sets compiled from oil well data. Thirty-seven thermal conductivity measurements on core samples were made and the effects of porosity and water saturation were corrected. Thermal conductivities of mudstone and sandstone range from 1.2 to 2.7 W/m K, with a mean of 2.0±0.5 W/m K after approximate correction. Heat flow at six sites in the Yinggehai Basin range from 69 to 86 mW/m², with a mean value of 79±7 mW/m². Thick sediments and high sedimentation rates resulted in a considerable radiogenic contribution, but also depressed the heat flow. Measurements indicate the radiogenic heat production in the sediment is 1.28 μW/m³, which contributes 20% to the surface heat flow. After subtracting radiogenic heat contribution of the sediment, and sedimentation correction, the average basal heat flow from basement is about 86 mW/m².Three stages of extension are recognized in the subsidence history, and a kinematic model is used to study the thermal evolution of the basin since the Cenozoic era. Model results show that the peak value of basal heat flow was getting higher and higher through the Cenozoic. The maximum basal heat flow increased from 65 mW/m² in the first stage to 75 mW/m² in the second stage, and then 90 mW/m² in the third stage. The present temperature field of the lithosphere of the Yinggehai Basin, which is still transient, is the result of the multistage extension, but was primarily associated with the Pliocene extension.     

川东地区龙潭组页岩岩性序列及勘探意义

川东地区龙潭组具有较大的页岩气勘探前景, 该地层沉积于海陆过渡环境, 沉积相变化快, 岩性复杂, 存在难以通过常规的矿物成分方法划分岩相以及当前岩相划分尚不精确的问题, 制约了该地区龙潭组页岩有利岩相带识别及勘探。本文基于岩心观察、野外剖面实测和薄片鉴定, 结合钻井的泥地比、单层岩性厚度, 建立了川东地区龙潭组7种特征岩性组合模式(泥页岩型、富泥含砂型、富泥含灰型、灰泥互层型、富灰含泥型、致密灰岩型和火成岩型); 综合TOC、孔隙度、含气性、脆性指数等页岩储层特征参数, 明确了不同岩性组合在龙潭组各段的平面分布规律。研究表明, 纵向上优势岩性组合主要为龙潭一段富泥含灰型和泥页岩型, 龙潭二段主要为泥页岩型、灰泥互层型和富泥含灰型。平面上龙潭一段优势岩性组合富泥含灰型主要分布在开州-云阳一带, 泥页岩型主要分布在重庆-綦江一带; 龙潭二段优势岩性组合泥页岩型分布在巴南-綦江一带, 灰泥互层型分布在达州一带, 富泥含灰型分布在万州-梁平-石柱一带。该项研究成果为川东地区龙潭组页岩气勘探提供了重要依据。

     

环青藏高原盆山体系东段新构造变形特征——以川西为例

介于扬子板块与青藏高原之间的川西前陆冲断带是环青藏高原盆山体系东段的重要组成部分,它是研究喜马拉雅构造运动对青藏高原东缘沉积盆地构造作用的重要场所。本文分别选取川西南段、川西北段和川北西段米仓山前的区域构造地质剖面来研究沉积地层在喜马拉雅运动中发生的构造变形特征。通过前陆冲断构造变形带的宽度、水平缩短量,山体隆升、盆地沉降,新构造对早期古构造的叠加与改造关系的研究,揭示出在环青藏高原盆山体系内,造山带与盆地边缘的冲断构造变形从造山带向克拉通盆地内扩展的同时受欧亚大陆与印度板块碰撞及其远程效应的空间位置限制,靠近青藏高原的川西南段到远离它的川北西段,新构造变形强度、新构造变形范围、盆山耦合程度具有依次降低等特征。这种受环青藏高原盆山体系控制的前陆冲断带构造变形具有明显的资环效应,特别是对油气资源的聚集与分布有重要的影响,控制了川西南段晚期次生气藏发育,川西北段和川北西段的早期原生气藏的发育。     

Burial and thermal history of the West Bashkirian sedimentary basins

The GALO system is applied to the numerical reconstruction of burial and thermal histories of the West Bashkirian lithosphere from the Riphean to the present. An analysis of the variation in tectonic subsidence of the basin during its development is utilized to estimate approximately the mantle heat flow variations. Our variant of basin evolution suggests that after cooling in the Early Riphean, the rather weak thermal reactivations have not led to considerable heating of the lithosphere in the study region. Surface heat flow decreased from relatively high values in the Early Riphean (60–70 mW/m² in the eastern area and 40–50 mW/m² in the western part) to present-day values of 32–40 mW/m². In spite of the relatively low temperature regime of the basin as a whole, a syn-rifting deposition of more than 10 km of limestone, shale and sandstone in the Riphean resulted in rather high temperatures (180–190 °C) at the base of present-day sedimentary blanket in the eastern area. In agreement with the observed data, computed present-day heat flow through the sediment surface increases slightly from 32 to 34 mW/m² near the west boundary of the region to 42 mW/m² near the boundary of the Ural Foldbelt, whereas the heat flow through the basement surface decreases slightly from 28–32 to 24–26 mW/m² in the same direction. The mantle heat flow is only 11.3–12.7 mW/m², which is considerable lower than mean heat flow of the Russian Platform (16–18 mW/m²) and comparable with the low heat flow of Precambrian shields.     

Thermal Lithospheric Thickness of the Sichuan Basin and its Geological Implications

Thermal lithospheric thickness is an important parameter in studying the tectonic-thermal evolution of basins and plate dynamics. Based on the measured geothermal data and thermophysical properties of the rocks, the thermal lithospheric thickness of the Sichuan Basin was calculated according to the principles of heat conduction in the crust and lithospheric mantle. The calculation results revealed that the thickness of the thermal lithosphere in the Sichuan Basin is 140–190 km and is unevenly distributed. The thickness of the thermal lithosphere in central Sichuan and southwestern Sichuan is less than 160 km, while that in the western Sichuan depression and eastern Sichuan is larger (~180 km). The distribution of the thermal lithospheric thickness in the basin has a good correlation with the geological units and the thickness of the sedimentary layers. The thickness of the thermal lithosphere in the depression area, which has thick sedimentary layers and the fault-fold zone with shallow crustal deformation and thickening, are larger than that in the basement uplifted area, which has thin sedimentary layers. The calculated thermal lithospheric thickness is in good agreement with the geophysical data and reflects the stable conduction temperature field in the Sichuan Basin. The present thermal regime and thermal lithospheric thickness of the Sichuan Basin indicate that flexural thickening of the lithosphere occurred in the eastern Sichuan fault-fold belt and the Longmen Mountain–Western Sichuan depression foreland basin system, while asthenospheric uplift occurred in the central Sichuan region, which were the result of the expansion of the Xuefeng orogeny from the east and the compression of the Tibetan Plateau from the west.     

四川多旋回叠合盆地的形成与演化

四川盆地是典型的经历了多期构造演化过程的克拉通盆地,在其多套沉积层序中富含天然气,天然气的开发利用历史悠久。近年来连续发现了普光、龙岗、合川、新场、九龙山和元坝等多个大气田。揭示四川盆地的形成演化过程,不仅为探讨克拉通盆地的成因机制奠立重要基础,而且为探索强烈构造活动环境之下油气有效聚集与保存机制提供重要线索。本文利用盆地内部最新的地面地质调查、钻探、重磁与地震等油气勘探资料,将周缘板块构造演化、造山带的发展与盆地的沉积充填密切结合,探讨四川盆地及邻区的盆地发展历史及其多旋回叠加过程。研究认为,四川盆地位于中上扬子克拉通之上,在显生宙期间,表现为板块构造围限下的陆内变形与盆地发育过程,即北侧为秦岭洋盆（早古生代为北秦岭洋,晚古生代—三叠纪为南秦岭洋）,西南侧为昌宁—孟连洋盆、金沙江—墨江洋盆、甘孜—理塘洋盆（主要为古特提斯洋盆）,东南侧为江南—雪峰陆内裂陷带（主要为早古生代裂陷）和西北侧龙门山陆内裂陷带（主要为晚古生代裂陷）,这些洋盆或裂陷带的开启与关闭使得四川盆地及邻区经历了原特提斯洋（Z—S）、古特提斯洋（D—T）与新特提斯洋（J—Q）3个演化阶段,每一阶段包括与洋盆打开有关的伸展阶段和与洋盆闭合有关的聚敛挤压阶段,这些构造作用在克拉通内部表现为伸展期（Z—O、D—P—T3x3、J12）盆地与挤压期（S、T3x46、J3—K1）盆地交替发育的特点,体现出盆地发展的旋回性。不同性质的旋回/盆地发生横向复合与垂向叠加形成多旋回盆地相叠加的“层、块”地质结构,受周缘盆—山体系多期构造作用的影响,这种“垂向分层、横向分块”的结构遭受了强烈改造,对油气聚集产生了深远的影响。