Apatite U–Pb geochronology and whole rock,Sr–Nd–Pb isotopic geochemistry of XV mafic-ultramafic intrusion,Bafq, Central Iran: Implications for petrogenesis and tectonic setting     

Sakine Amraei  Mohammad Yazdi  Liang Qiu  Chang-Zhi Wu  Lei Chen  Bertrand Moine  Majid Ghasemi Siani  Qihui Zhang  Shahrokh Rajabpour 《Island Arc》2024,33(1):e12514

The XV mafic-ultramafic intrusion is located in the western part of the Posht-e-Badam Block (PBB) within the Central Iranian Micro-Continent (CIMC). Petrographically, the intrusion is composed of gabbro and pyroxenite. Apatite U–Pb dating has established the crystallization age of this intrusion to be 363 ± 67 Ma. The XV intrusive rocks are tholeiitic to slightly calc-alkaline in nature and are characterized by an enrichment of large ion lithophile elements (LILE) and light rare earth elements (LREE) relative to high field strength elements (HFSE) and Heavy Rare Earth Elements (HREE), respectively. The major oxide elements display continuous trends relative to SiO₂. The ⁸⁷Sr/⁸⁶Sr(i) ratios range from 0.7045 to 0.7056, and the εNd(i) values range from 2.63 to 3.30. In addition, the ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb ratios exhibit a narrow range, varying from 18.68 to 18.70, 15.67 to 15.71, and 38.84 to 38.99, respectively. The geochemical and isotopic characteristics suggest that the parental magma was derived from a Sub- Continental Lithospheric Mantle (SCLM) that was modified by oceanic slab-derived components. The locations of the XV intrusive rocks in εNd(i) versus TDM (Ga) and Nb/La versus discrimination diagrams further support this conclusion. Fractional crystallization is identified as the dominant process influencing the formation of distinct lithological units within the XV intrusive rocks. Our newly presented isotopic and geochronological data, when considered in the regional context, suggest that the XV intrusive rocks were formed in an extensional tectonic setting. In this scenario, upwelling from the asthenospheric mantle induced heating, leading to the melting of previously subduction-modified SCLM. Comparative analysis with previously published ages indicates that extensional magmatism in the PBB continued into the Middle Paleozoic.  相似文献   

Farola Monte Hermoso: Fission-track Dating of Darwin's mammals deposit in Argentina     

GIULIO BIGAZZI  FRANCESCO PAOLO BONADONNA  GIOVANNI ZANCHETTA 《第四纪科学杂志》1996,11(5):423-426

The Montehermosan Land Mammal Age has been etablished by fission-track dating of the mammal deposit of Farola Monte Hermoso. The fossil bones were found in the lowest part of the outcrop, consisting of fluvially derived clay and silt. The erosional surface between the lowest portion and the overlying aeolian sands is charcterised by a compact unit of rounded volcanic glass shards; a second fresh volcanic ash level is about 1 m above. EDS analyses and fission-track age analyses were performed on the two levels. The age determined for the lower volcanic ash level, 1.7 ± 0.4 Ma, is a minimum age for the Chapadmalalan mammal assemblage and a maximum age for the Uquian mammal assemblage in the Bonaerense area.  相似文献   

中、新生代天山隆升过程及其与准噶尔、阿尔泰山比较研究   总被引：49，自引：4，他引：45  

郭召杰  张志诚  吴朝东  方世虎  张锐 《地质学报》2006,80(1):1-15

根据穿越天山地质剖面观察、系统裂变径迹(FT)测年年龄与热演化模拟结果分析,并综合前人研究结果,天山陆内造山带中、新生代主要经历2次明显的隆升事件,分别为晚侏罗世—早白垩世和中新世以来(25~0Ma)。从天山地区磷灰石FT年龄结果来看,主要记录了早期隆升年龄,但热演化模拟结果显示普遍经历了中新世以来的快速隆升。在天山北缘从盆山边缘的近25Ma开始隆升到前缘带的现今活动,表明天山陆内造山带在隆升的同时还逐渐“增生”扩展。系统研究和分析表明,东西准噶尔和阿尔泰地区则主要记录了晚中生代以来的持续隆升过程,新生代构造活动不明显或强度相对天山要弱。上述事实表明,天山及其中亚地区新生代的陆内活动是受喜马拉雅碰撞与青藏高原隆升的影响,具有向北渐弱的特征。  相似文献   

碳酸盐岩层系热历史恢复的有机质自由基古温标研究   总被引：2，自引：1，他引：1  

邱楠生  李慧莉  金之钧  朱映康 《地质学报》2006,80(3):390-397

古温标是恢复沉积盆地热演化历史的重要指标之一。目前,有众多的古温标用于碳酸盐岩层系热历史的恢复,既有沥青反射率(Rb)、牙形石色变指数(CAI)、镜状体反射率、有机质自由基浓度(N)、激光拉曼光谱等有机质古温标,也有矿物的裂变径迹热定年、岩石声发射、伊利石结晶度等矿物古温标,但他们都有不同的适用范围。本文针对有机质自由基浓度作为古温标在碳酸盐岩层系热历史恢复中的应用进行了探索研究。根据不同受热时间和加热温度下的热模拟试验,分析了型和型有机质的自由基浓度的热演化特征,得到了自由基浓度与时间-温度(TTI)的定量关系;由此建立了自由基浓度(N)与时间-温度(TTI)的定量模型并将之应用于塔里木盆地TZ12井的热历史研究。依据自由基浓度古温标模拟得到的TZ12井区奥陶纪时期的古地温梯度为3℃/100m左右,该结果与前人对该地区热史研究的结论及本研究中依据磷灰石裂变径迹模拟的结果相一致。对于经历了多期构造运动的下古生界碳酸盐岩层系的热史恢复,最好是多种古温标并用,多种方法综合运用,才能精确地恢复有机质的热演化史。  相似文献   

渤海钻孔物源示踪和河流沉积物扩散研究:碎屑锆石U-Pb年龄和磷灰石原位地球化学元素双重约束     

林旭  刘静  吴中海  李长安  刘海金 《地质力学学报》2021,27(2):304-316

锆石和磷灰石是河流沉积物中常见的副矿物,由于各自的U-Pb年龄组成和原位地球化学元素组成在不同区域内存在显著差异,是进行河流物源示踪研究的理想矿物.基于此,利用在环渤海湾盆地主要汇入河流已发表的碎屑锆石U-Pb年龄,结合盆地晚第四纪钻孔的近地表碎屑物质的锆石U-Pb年龄,综合Kolmogorov-Smirnov统计方法...  相似文献   

MEASUREMENT PROCEDURE OF SINGLE-GRAIN APATITE(U-Th)/He DATING AND ITS VALIDATION BY DURANGO APATITE STANDARD          下载免费PDF全文

WANG Ying  ZHENG De-wen  WU Ying  LI You-juan  WANG Yi-zhou 《地震地质》2017,39(6):1143-1157

(U-Th)/He isotopic dating has been developed very quickly in recent years, due to the recognition that the thermal history of rock at low temperature can be effective revealed by such dating method. In particular, He closure temperature in apatite (40~80℃) is very low, so apatite (U-Th)/He ages can reflect the thermal history information of the low-temperature stage, and have a good application prospect in the field of low-temperature thermal chronology. However, because of many influence factors and complicated measurement procedures, the development of apatite He dating in China remains in its early stage. In this study, a measurement procedure was established at the (U-Th)/He dating laboratory of Institute of Geology, China Earthquake Administration. We measured the daughter isotopic helium by diode laser heating four batches of a total seventy-five grains of Durango apatite in an Alphachron helium mass spectrometry system. Then the apatite grains were dissolved to precisely measure the concentration of parent nuclides (U, Th)using the solution isotope dilution method through an automatic sampling ICP-MS (Agilent 7900). Results show that the Th/U values of Durango apatite grains were in the range of 17.23 to 23.60, while all the 75ages were in the range of 28.61 to 34.51Ma with an average of (31.71±1.55)Ma (1σ), which are consistent with the international calibrated ages.  相似文献   

阿尔金山脉新生代隆升-剥露过程   总被引：24，自引：2，他引：22  

陈正乐  宫红良  李丽  王小凤  陈柏林  陈宣华 《地学前缘》2006,13(4):91-102

阿尔金山脉位于青藏高原北缘。文中主要是利用磷灰石裂变径迹测年分析,探讨阿尔金山脉的隆升和剥露过程。来自阿尔金山脉34个花岗岩、花岗闪长岩和片麻岩样品中磷灰石的裂变径迹测试结果表明,阿尔金山脉存在至少5个阶段的剥露作用,反演出阿尔金山脉具有多期次、阶段性的隆升特征,并存在差异性:EW向的阿尔金北缘拉配泉—红柳沟山体隆升-剥露时间早(61~34Ma);NE向且末—茫崖山脉的主要隆升时间位于始新世晚期—中新世(42~11Ma);沿阿尔金(主)断裂山体的隆升-剥露最为年轻,存在三期主要的剥露作用:10·2~7·3、5·5~4·5和2·1~1·8Ma。结合区域磷灰石测年数据、区域变形事件及其阿尔金断裂走滑历史分析,推测阿尔金山脉在晚白垩世曾有过初期隆升和剥露,古近纪的剥露局限于阿尔金山脉北缘EW向的山脉,始新世晚期—中新世、上新世晚期和早更新世的山脉剥露作用遍及了青藏高原北缘山脉,8Ma是青藏高原抬升和变形的一期重要构造事件发生时间;前陆盆地和阿尔金山间盆地的沉积作用研究也显示了阿尔金山脉的隆升剥露过程与阿尔金断裂的走滑及其相关盆地沉积构造-演化具有很好的耦合关系。  相似文献   

应用流体包裹体和磷灰石裂变径迹研究古地温--以辽河盆地东部凹陷为例   总被引：1，自引：0，他引：1  

纪玉峰  聂占福  韦忠红  李扬  魏小红 《矿物岩石地球化学通报》2006,25(1):98-104

以太阳岛构造和大平房构造为例,利用流体包裹体显微测温和磷灰石裂变径迹分析方法恢复了辽河盆地东部凹陷第三系的古地温。流体包裹体研究表明,32 Ma和25 Ma时研究区两期排烃运移高峰均发生于高的地温场。磷灰石裂变径迹分析得到太阳岛构造古地温梯度为3.79℃/hm,大平房构造古地温梯度为3.24℃/hm。古地温梯度均高于现今地温梯度,且呈现古地温梯度由早到晚降低的趋势。这些研究结果与辽河盆地的区域地质背景相一致。  相似文献   

Low‐temperature thermochronology of the Mt Painter Province,South Australia     

M. M. Mitchell  B. P. Kohn  P. B. O'Sullivan  M. J. Hartley  D. A. Foster 《Australian Journal of Earth Sciences》2013,60(3):551-563

Apatite fission track results are reported for 26 outcrop samples from the Mt Painter Inlier, Mt Babbage Inlier and adjacent Neoproterozoic rocks of the northwestern Curnamona Craton of South Australia. Forward modelling of the data indicates that the province experienced variable regional cooling from temperatures >110°C during the Late Palaeozoic (Late Carboniferous to Early Permian). The timing of this cooling is similar to that previously reported from elsewhere in the Adelaide Fold Belt and the Curnamona Craton, suggesting that the entire region underwent extensive Late Palaeozoic cooling most likely related to the waning stages of the Alice Springs or Kanimblan Orogenies. Results from the Paralana Fault Zone indicate that the eastern margin of the Mt Painter Inlier experienced a second episode of cooling (～40–60°C) during the Paleocene to Eocene. The entire region also experienced significant cooling (less than ～40°C) during the Late Cretaceous to Palaeogene in response to unroofing and/or a decrease in geothermal gradient. Regional cooling/erosion during this time is supported by: geomorphological and geophysical evidence indicating Tertiary exhumation of at least 1 km; Eocene sedimentation initiated in basins adjacent to the Flinders and Mt Lofty Ranges sections of the Adelaide Fold Belt; and Late Cretaceous ‐ Early Tertiary cooling previously reported from apatite fission track studies in the Willyama Inliers and the southern Adelaide Fold Belt. Late Cretaceous to Palaeogene cooling is probably related to a change in stress field propagated throughout the Australian Plate, and driven by the initiation of sea‐floor spreading in the Tasman Sea in the Late Cretaceous and the Eocene global plate reorganisation.  相似文献   

粤北石人嶂钨矿区角闪辉长岩地球化学、年代学特征及其地质意义     

秦锦华  王登红  黄凡  赵如意  刘士岩  洪文亮  魏东 《矿床地质》2023,42(5):978-1002

石人嶂钨矿区发育的角闪辉长岩与钨矿密切共生,研究该矿区对认识粤北地区区域地质演化、深部岩浆信息以及区域基性岩与成钨作用关系研究意义重大,但到目前为止,尚未开展相关系统的研究。文章报道了角闪辉长岩的锆石和磷灰石U-Pb年代学、地球化学资料。磷灰石U-Pb年龄指示角闪辉长岩的结晶年龄为（171±14） Ma,形成于燕山早期晚阶段古太平洋板块俯冲背景下的岩石圈伸展的构造环境,其中,锆石为捕获锆石,具有3组年龄,分别记录了区域古元古代陆核增生,新元古代古华南板块的聚合和裂解,早中生代华南板块与华北板块,印支地块聚合的后造山伸展等多起构造事件。角闪辉长岩具有低Si、K、Mn,高Ca、Fe、Mg、Na、Ti的特征,富集Rb、Ta、Zr、Ti等,亏损Ba、Nb、Sr、Hf、Be、Cs、U、Th等元素,表明其源区具有E-MORB型富集地幔的属性。角闪辉长岩的形成主要受控于软流圈地幔的部分熔融。同时,由于角闪辉长岩的高氧逸度的特征及其较石人嶂钨矿成矿更早,角闪辉长岩的存在可能主要是为后期的钨矿化的叠加提供部分Ca、Fe等元素,并为富矿流体的运移提供通道。  相似文献