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1.
天山是中亚造山带重要组成部分,其中-新生代构造热演化及隆升剥露史研究是认识中亚造山带构造变形过程与机制的关键.本文应用磷灰石(U-Th)/He技术重建中天山南缘科克苏河地区中-新生代构造热演化及隆升剥蚀过程.磷灰石(U-Th)/He数据综合解释及热演化史模拟表明该地区至少存在晚白垩世、早中新世、晚中新世3期快速隆升剥蚀事件,起始时间分别为~90Ma、~13Ma及~5Ma,且这3期隆升剥蚀事件在整个天山地区具有广泛的可对比性.相对于磷灰石裂变径迹,磷灰石(U-Th)/He年龄记录了中天山南缘地质演化史中更新和更近的热信息,即中天山在晚中新世(~5 Ma)快速隆升剥蚀,其剥蚀速率为~0.47mm·a~(-1),剥蚀厚度为~2300m.总体上,中天山科克苏地区隆升剥蚀起始时间从天山造山带向昭苏盆地(由南向北)逐渐变老,表明了中天山南缘隆升剥蚀存在不均一性,并发生了多期揭顶剥蚀事件. 相似文献
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《中国科学:地球科学》2010,(12)
塔里木盆地早古生代碳酸盐岩沉积时期的热历史由于缺乏有效的古温标进行热史恢复,一直是困扰该区下古生界烃源岩演化研究的难题.磷灰石和锆石的(U-Th)/He热定年技术是近年来用于沉积盆地热史研究的新技术,可以用来揭示地层的构造抬升和热历史.本文利用塔里木盆地典型井中古生界层系的古温标来恢复古生代的热史.这些井在海西期长期隆升、遭受强烈的剥蚀、后期埋藏深度较小,因而古生界层系中的古温标可以保留原始热信息,从而反映古生代的温度状况.本文通过对这些钻井样品进行磷灰石和锆石(U-Th)/He年龄测试,并结合磷灰石裂变径迹和等效镜质体反射率等古温标,综合模拟计算了塔里木盆地不同构造单元的KQ1和T1井早古生代的构造-热演化历史.模拟结果表明,塔里木盆地塔东北和巴楚隆起区古生代热演化存在差异.巴楚隆起区T1井在寒武纪末期的古地温梯度仅为28～30℃/km,奥陶纪的地温梯度增高至30～33℃/km之间,志留-泥盆纪地温梯度为31～34℃/km;塔东北的KQ1井区奥陶纪的地温梯度可达35℃/km,志留-泥盆纪地温梯度为32～35℃/km.因此,(U-Th)/He年龄结合其他古温标综合模拟的方法可以很好地揭示沉积盆地的热历史,特别是该方法为塔里木盆地早古生代的热史恢复提供了新的途径. 相似文献
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库车前陆盆地蕴藏着丰富的油气资源,然而盆地中新生代的构造热演化史一直缺乏有效的研究,制约了油气的勘探.本文测试了吐孜2井磷灰石、锆石(U-Th)/He年龄数据,建立了He年龄随现今温度/深度变化的关系,确定该区磷灰石(U-Th)/He体系封闭温度为89℃.综合利用(U-Th)/He及镜质体反射率(Ro)数据模拟恢复了库车盆地吐孜2井中新生代热演化史,结果表明库车盆地吐孜洛克背斜形成起始时间约为5Ma,新生代抬升剥蚀量平均约为670m,平均抬升剥蚀速率为0.133mm/a.根据新生代吐孜洛克背斜的构造演化分析确定了气源断裂活动及圈闭形成的时期,揭示了吐孜洛克背斜天然气成藏时间为5Ma以后,且烃源岩生排烃、断裂活动及圈闭形成的时间具有良好的匹配关系,这是吐孜洛克油气田形成的关键因素之一.本文应用(U-Th)/He技术研究沉积盆地构造热演化史,对库车盆地油气勘探具有重要的意义. 相似文献
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(U-Th)/He热定年技术是近年来用于沉积盆地热史研究的新技术,目前主要是利用磷灰石和锆石的He年龄来揭示地层的构造抬升和热历史.本文依据塔里木盆地钻井样品的实测磷灰石和锆石(U-Th)/He年龄数据,初步得出了该地区磷灰石(U-Th)/He年龄的封闭温度为85℃,并建立了深度/温度－年龄演化模式;锆石则未达到其较高的封闭温度.综合利用本次实测的He年龄数据结合磷灰石裂变径迹和等效镜质组反射率等古温标,模拟计算了塔里木盆地孔雀1井（KQ1）自奥陶纪末期以来的热历史.模拟结果表明,孔雀1井区奥陶纪末期的地温梯度可达35.5℃/km,志留纪—泥盆纪时期的地温梯度为33.3～34.5℃/km,白垩纪末期地温梯度27.6℃/km左右.因此,(U-Th)/He年龄结合其他古温标综合模拟的方法可以很好地揭示沉积盆地的热历史.特别是该技术为缺乏常规古温标的塔里木盆地下古生界碳酸盐岩层系所经受热史的恢复提供了新的方法. 相似文献
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本文通过峨眉山基底卷入构造带低温热年代学(磷灰石和锆石裂变径迹、锆石(U-Th)/He)研究,结合典型构造-热结构特征诠释峨眉山晚中-新生代冲断扩展变形与热年代学耦合性.峨眉山磷灰石裂变径迹(AFT)和锆石(U-Th)/He(ZHe)年龄值分别为4~30Ma和16~118Ma.ZHe年龄与海拔高程关系揭示出ZHe系统抬升剥蚀残存的部分滞留带(PRZ).低温热年代学年龄与峨眉山构造分带性具有明显相关性特征:万年寺逆断层上盘基底卷入构造带AFT年龄普遍小于10Ma,万年寺逆断层下盘扩展变形带AFT年龄普遍大于10 Ma;且空间上AFT年龄与断裂带具有明显相关性,它揭示出峨眉山扩展变形带中新世晚期以来断层冲断缩短构造活动.低温热年代学热史模拟揭示峨眉山构造带晚白垩世以来的多阶段性加速抬升剥蚀过程,基底卷入构造带岩石隆升幅度大约达到7~8km,渐新世以来抬升剥蚀速率达0.2~0.4mm·a-1,其新生代多阶段性构造隆升动力学与青藏高原多板块间碰撞过程及其始新世大规模物质东向扩展过程密切相关. 相似文献
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本文通过背斜褶皱变形与低温热年代学年龄(磷灰石和锆石(U-Th)/He、磷灰石裂变径迹)端元模型研究,约束低起伏度、低斜率地貌特征的四川盆地南部地区新生代隆升剥露过程.四川盆地南部沐川和桑木场背斜地区新生代渐新世-中新世发生了相似的快速隆升剥露过程(速率为~0.1 mm/a、现今地表剥蚀厚度1.0~2.0 km),反映出盆地克拉通基底对区域均一性快速抬升冷却过程的控制作用.川南沐川地区磷灰石(U-Th)/He年龄值为~10-28.6 Ma, 样品年龄与古深度具有明显的线性关系,揭示新生代~10-30 Ma以速率为0.12±0.02 mm/a的稳态隆升剥露过程.桑木场背斜地区磷灰石裂变径迹年龄为~36-52 Ma,古深度空间上样品AFT年龄变化不明显(~50 Ma)、且具有相似的径迹长度(~12.0 μm).磷灰石裂变径迹热演化史模拟表明桑木场地区经历三个阶段热演化过程:埋深增温阶段(~80 Ma以前)、缓慢抬升冷却阶段(80-20 Ma)和快速隆升剥露阶段(~20 Ma-现今),新生代隆升剥露速率大致分别为~0.025 mm/a和~0.1 mm/a.新生代青藏高原大规模地壳物质东向运动与四川盆地克拉通基底挤压,受板缘边界主断裂带差异性构造特征控制造就了青藏高原东缘不同的边界地貌特征. 相似文献
7.
库车前陆盆地蕴藏着丰富的油气资源,然而盆地中新生代的构造热演化史一直缺乏有效的研究,制约了油气的勘探.本文测试了吐孜2井磷灰石、锆石（U-Th）/He年龄数据,建立了He年龄随现今温度/深度变化的关系,确定该区磷灰石（U-Th）/He体系封闭温度为89℃.综合利用（U-Th）/He及镜质体反射率（Ro）数据模拟恢复了库车盆地吐孜2井中新生代热演化史,结果表明库车盆地吐孜洛克背斜形成起始时间约为5 Ma,新生代抬升剥蚀量平均约为670 m,平均抬升剥蚀速率为0.133 mm/a.根据新生代吐孜洛克背斜的构造演化分析确定了气源断裂活动及圈闭形成的时期,揭示了吐孜洛克背斜天然气成藏时间为5 Ma以后,且烃源岩生排烃、断裂活动及圈闭形成的时间具有良好的匹配关系,这是吐孜洛克油气田形成的关键因素之一.本文应用（U-Th）/He技术研究沉积盆地构造热演化史,对库车盆地油气勘探具有重要的意义. 相似文献
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10.
《中国科学:地球科学》2016,(3)
天山造山带晚古生代以来的隆升剥露过程与带内矿床形成后的保存潜力密切相关.本文报道了新的角闪石/斜长石Ar-Ar年龄和锆石/磷灰石(U-Th)/He年龄,为重建南天山中段地区欧西达坂岩体完整的构造-热演化历史提供年代学基础,结合前人研究成果分析了冷却速率及剥蚀速率变化特征,对南天山中段晚古生代以来的热演化历史及隆升剥蚀历史进行了探讨.同位素定年结果显示,角闪石Ar-Ar坪年龄为(382.6±3.6)Ma,斜长石Ar-Ar加权平均年龄为(265.8±4.9)Ma,锆石与磷灰石(U-Th)/He年龄分别为(185.8±4.3)和(31.1±2.9)Ma.热演化历史及模拟结果表明,南天山中段地区晚古生代至今的构造-热演化历史可以大致分为5个阶段:(1)志留纪末至晚泥盆世岩体平均冷却速率约7.84℃/Myr;(2)晚泥盆世至中二叠世末期,岩体的平均冷却速率约2.07℃/Myr;(3)中二叠世末到始新世中期岩体平均冷却速率降至0.68℃/Myr,此期间总体地质运动较为平缓;(4)新生代始新世期间(约46~35Ma)南天山中段地区发生了一期快速隆升剥蚀事件,岩体冷却速率突升至5.00℃/Myr,剥蚀量达到1.83km,平均剥蚀速率0.17mm/a;(5)始新世中期(约35Ma)至今,平均冷却速率约为1.14℃/Myr,隆升速度仍然较快,剥蚀量约为1.33km,平均剥蚀速率约0.04mm/a.新生代以来天山的剧烈隆起抬升受控于印亚碰撞的远程效应,远程作用在天山的响应具有一定的滞后效应. 相似文献
11.
通过大量野外地质调查和深部物探（地震剖面、MT和重力）综合构造解释，在位于东起八盘水磨，西对乌鲁克恰特以西的南天山前陆冲断带中，确定了阿图什－八盘水磨反冲构造系统及其三角带构造；该反冲系统由小阿图什－八盘水磨和乌尔－喀拉套山反冲构造系统及小阿图什－乌鲁克恰特被变形的反冲构造系统组成；即在以往认为南天山向塔里木盆地大规模中推覆的地区，塔里木盆地美国层第四纪以来沿多组滑脱面向天山新生代造山带反冲推覆。塔里木盆地反冲构造系统发育的区域基底埋深往往大于10km，对应麦盖提基底构造下凹区，而相邻柯坪塔格薄皮推覆构造系统发育的区域基底埋深一般小于10km,对应巴楚基底构造上隆区；逆冲和反冲构造转换带基底埋深约10km,平衡剖面恢复表明弧形逆冲和反冲构造顶部分别为逆冲和反冲位移量最大位置。 相似文献
12.
BURIAL AND EXHUMATION OF THE XIGAZE FORE-ARC BASIN FROM LOW TEMPERATURE THERMOCHRONOLOGICAL EVIDENCE
The Xigaze fore-arc basin is adjacent to the Indian plate and Eurasia collision zone. Understanding the erosion history of the Xigaze fore-arc basin is significant for realizing the impact of the orogenic belt due to the collision between the Indian plate and the Eurasian plate. The different uplift patterns of the plateau will form different denudation characteristics. If all part of Tibet Plateau uplifted at the same time, the erosion rate of exterior Tibet Plateau will be much larger than the interior plateau due to the active tectonic action, relief, and outflow system at the edge. If the plateau grows from the inside to the outside or from the north to south sides, the strong erosion zone will gradually change along the tectonic active zone that expands to the outward, north, or south sides. Therefore, the different uplift patterns are likely to retain corresponding evidence on the erosion information. The Xigaze fore-arc basin is adjacent to the Yarlung Zangbo suture zone. Its burial, deformation and erosion history during or after the collision between the Indian plate and Eurasia are very important to understand the influence of plateau uplift on erosion.
In this study, we use the apatite fission track(AFT)ages and zircon and apatite(U-Th)/He(ZHe and AHe)ages, combined with the published low-temperature thermochronological age to explore the thermal evolution process of the Xigaze fore-arc basin. The samples' elevation is in the range of 3 860~4 070m. All zircon and apatite samples were dated by the external detector method, using low~U mica sheets as external detectors for fission track ages. A Zeiss Axioskop microscope(1 250×, dry)and FT Stage 4.04 system at the Fission Track Laboratory of the University of Waikato in New Zealand were used to carry out fission track counting. We crushed our samples finely, and then used standard heavy liquid and magnetic separation with additional handpicking methods to select zircon and apatite grains.
The new results show that the ZHe age of the sample M7-01 is(27.06±2.55)Ma(Table 2), and the corresponding AHe age is(9.25±0.76)Ma. The ZHe and AHe ages are significantly smaller than the stratigraphic age, indicating suffering from annealing reset(Table 3). The fission apatite fission track ages are between(74.1±7.8)Ma and(18.7±2.9)Ma, which are less than the corresponding stratigraphic age. The maximum AFT age is(74.1±7.8)Ma, and the minimum AFT age is(18.7±2.9)Ma. There is a significant north~south difference in the apatite fission track ages of the Xigaze fore-arc basin. The apatite fission track ages of the south part are 74~44Ma, the corresponding exhumation rate is 0.03~0.1km/Ma, and the denudation is less than 2km; the apatite fission track ages of the north part range from 27 to 15Ma and the ablation rate is 0.09~0.29km/Ma, but it lacks the exhumation information of the early Cenozoic. The apatite(U-Th)/He age indicates that the north~south Xigaze fore-arc basin has a consistent exhumation history after 15Ma.
The results of low temperature thermochronology show that exhumation histories are different between the northern and southern Xigaze fore-arc basin. From 70 to 60Ma, the southern Xigaze fore-arc basin has been maintained in the depth of 0~6km in the near surface, and has not been eroded or buried beyond this depth. The denudation is less than the north. The low-temperature thermochronological data of the northern part only record the exhumation history after 30Ma because of the young low-temperature thermochronological data. During early Early Miocene, the rapid erosion in the northern part of Xigaze fore-arc basin may be related to the river incision of the paleo-Yarlungzangbo River. The impact of Great Count Thrust on regional erosion is limited. The AHe data shows that the exhumation history of the north-south Xigaze fore-arc basin are consistent after 15Ma. In addition, the low-temperature thermochronological data of the northern Xigaze fore-arc basin constrains geographic range of the Kailas conglomerate during the late Oligocene~Miocene along the Yarlung Zangbo suture zone. The Kailas Basin only develops in the narrow, elongated zone between the fore-arc basin and the Gangdese orogenic belt.
The southern part of the Xigaze fore-arc basin has been uplifted from the sea level to the plateau at an altitude of 4.2km, despite the collision of the Indian plate with the Eurasian continent and the late fault activity, but the plateau has been slowly denuded since the early Cenozoic. The rise did not directly contribute to the accelerated erosion in the area, which is inconsistent with the assumption that rapid erosion means that the orogenic belt begins to rise. 相似文献
13.
本文分析了塔里木盆地大量实测镜质体反射率(Ro)数据,显示盆地西北部石炭系与二叠系之间Ro值演化不连续,记录了石炭-二叠纪间发生的构造-热事件,是地层抬升剥蚀和高温热事件共同作用的结果.热史模拟得出盆地在石炭纪末地温梯度开始升高,至~300 Ma达到峰值,分布在4.8~5.6℃/100m之间,早二叠世迅速降低,随后进入缓慢稳定降低阶段.区域上高温热效应空间分布与塔里木大火成岩省的分布范围存在较好的相关性,但早于大规模玄武岩喷发的时间(290—288Ma),且后者热效应范围有限.因此推断这种高温异常是大规模的深部岩浆活动,即深部岩浆房相对长时间热烘烤的结果.该研究结果为塔里木盆地热演化机制及相关热效应提供了新的线索. 相似文献
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本文综合运用磷灰石-锆石裂变径迹和（U-Th）/He、镜质体反射率及盆地模拟等手段,深入细致地探讨了中扬子江汉平原簰洲湾地区中、新生代构造-热史演化过程.研究结果表明,研究区中-新生代大规模构造抬升剥蚀、地层冷却事件始于早白垩世（140-130 Ma）;大规模抬升冷却过程主要发生在早白垩世中后期至晚白垩世.研究区虽然可能存在一定厚度的晚白垩世-古近纪地层沉积,总体沉积规模相对较小.综合分析认为,区内应该存在较大厚度的中侏罗统或/和上侏罗统乃至早白垩世地层的沉积;而现今残存中生代中、上侏罗统地层相对较薄,主要是由于后期持续构造抬升剥蚀造成的,估计总剥蚀厚度约4300 m左右.区内中生代地层在早白垩世达到最大古地温,而不是在古近纪沉积末期;上三叠统地层最大古地温在170~190℃之间.热史分析结果表明,区内古生代古热流相对稳定,平均热流在53.64 mW·m-2;早侏罗世末期古热流开始降低,在早白垩世初期古热流约为48.38 mW·m-2. 相似文献
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江南隆起位于扬子与华夏地块的碰撞汇聚带,是研究华南大地构造演化的关键地质单元.本文采用磷灰石裂变径迹及(U-Th-Sm)/He年龄分布特征定性分析与径迹长度分布数据定量模拟相结合,主要研究了幕阜山岩体新生代的隆升与剥蚀过程,并在此基础上结合区域构造背景, 对其构造-热演化之间的关系进行了探讨.自晚白垩世持续隆升以来,幕阜山岩体经历的平均剥蚀厚度约4800 m.在不同岩体间,隆升过程及幅度存在差异,空间上具有非均匀性.热史结果显示幕阜山岩体经历了3期剥蚀, 其中两期快速剥蚀分别发生在晚白垩世-古近纪(80~50 Ma)和10 Ma以来,而这之间为一期缓慢剥蚀过程.研究区古近纪的快速剥蚀反映了中-下扬子喜山期大规模伸展断陷作用造成的肩部块体快速剥蚀事件; 约10 Ma以来的快速剥蚀是对太平洋板块向西运动的响应.幕阜山岩体自燕山晚期以来的隆升剥蚀作用具有良好的盆地沉积响应, 三期隆升剥蚀事件与研究区构造演化的动力学背景相吻合. 相似文献
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Bin Zhang Wen Chen JingBo Sun Shun Yu JiYuan Yin Jie Li Yan Zhang XinYu Liu Li Yang Xia Yuan 《中国科学:地球科学(英文版)》2016,59(2):349-361
The uplift and exhumation process in the Tianshan orogen since the late Paleozoic were likely related to the preservation of ore deposits. This study involved reconstructing the whole tectonic thermal history of the Ouxidaban pluton in central South Tianshan Mountains based on hornblende/plagioclase Ar-Ar and zircon/apatite(U-Th)/He methods. The thermal history and uplift process of central South Tianshan Mountains since the late Paleozoic were analyzed according to the results of previous works and cooling/exhumation rate features. The hornblende yields a plateau age of 382.6±3.6 Ma, and the plagioclase yields a weighted mean age of 265.8±4.9 Ma. The Ouxidaban pluton yields weighted mean zircon(U-Th)/He age of 185.8±4.3 Ma and apatite(U-Th)/He age of 31.1±2.9 Ma, respectively. Five stages of tectonic thermal history of South Tianshan Mountains since the late Paleozoic could be discriminated by the cooling curve and modeling simulation:(1) from the latest Silurian to Late Devonian, the average cooling rate of the Ouxidaban pluton was 7.84°C/Ma;(2) from the Late Devonian to the latest Middle Permian, the average cooling rate was about 2.07°C/Ma;(3) from the latest Middle Permian to the middle Eocene, the cooling rate decreased to about 0.68°C/Ma, suggesting that the tectonic activity was gentle at this time;(4) a sudden increase of the cooling rate(5.00°C/Ma) and the exhumation rate(0.17 mm/a), and crustal exhumation of ~1.83 km indicated that the Ouxidaban pluton would suffer a rapid uplift event during the Eocene(~46?35 Ma);(5) since the middle Eocene, the rapid uplift was sustained, and the average cooling rate since then has been 1.14°C/Ma with an exhumation rate of about 0.04 mm/a and an exhumation thickness of 1.33 km. The strong uplift since the Cenozoic would be related to a far-field effect from the Indian and Eurasian plates' collision. However, it was hysteretic that the remote effect was observed in the Tianshan orogenic belt. 相似文献