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1.
Abstract

New zircon laser ablation inductively coupled plasma mass spectrometry and secondary ion mass spectroscopy U–Pb ages, and Hf isotope and whole-rock geochemical data are reported for Mesozoic igneous rocks from the eastern margin of the Songnen–Zhangguangcai Range Massif, Northeast China, in order to document the petrogenesis of the igneous rocks and reconstruct the early Mesozoic tectonic setting of the region. Zircons from five representative igneous rocks are euhedral–subhedral and display oscillatory growth zoning or striped absorption in cathodoluminescence images, suggesting a magmatic origin. The dating results indicate that granite, gabbro, and rhyolite from the eastern Songnen–Zhangguangcai Range Massif formed during Late Triassic (204–211 Ma). The Late Triassic granitoids and rhyolites have an affinity to A-type granites or rhyolites. Their zircon εHf(t) values and Hf two-stage model ages range from –3.8 to +3.8 and from 999 to 1485 Ma, respectively, indicating that their primary melts were derived from the partial melting of the Meso-Proterozoic crust. The geochemistry of coeval gabbros, which reflects primary magma composition, shows a significant large ion lithophile element (e.g. Ba and Sr) enrichment and high field strength element (i.e. Zr, Hf, Nb, Ta, and Ti) depletion. Based on zircon εHf(t) values (–4.2 to +2.8) and Hf single-stage model ages (746–1031 Ma), we conclude that the mafic magma is the product of partial melting of lithospheric mantle that was metasomatically enriched by fluids derived from the subducted oceanic crust. The Late Triassic magmatism along the eastern margin of the Eurasian continent has bimodal magma compositions, indicating an extensional setting after the final closure of the Palaeo-Asian Ocean rather than being related to subduction of the Palaeo-Pacific Plate beneath the Eurasian continent. The occurrence of Late Triassic igneous rocks on the eastern side of the Mudanjiang Fault suggests that this fault does not represent the suture zone between the Songnen–Zhangguangcai Range and Jiamusi massifs.  相似文献   

2.
We present new zircon U–Pb and Hf isotopic as well as whole-rock geochemical data for volcanic rocks from the eastern margin of the Xing’an Massif, Northeast China, in order to further our understanding of the suture location between the Xing’an and Songnen–Zhangguangcai Range massifs. Zircon secondary ion mass spectrometry U–Pb dating indicates that the volcanic rocks formed during the Early–Middle Ordovician (473–463 Ma). Compared with the coeval Moguqi basalts (rare earth element [REE] = 171–183 ppm; εHf(t) = +0.3 to +2.7; TDM1 = 1074–977 Ma), the Duobaoshan andesites exhibit lower overall REE abundances (109–131 ppm) with relatively high heavy REE contents, stronger high-field-strength element depletion, higher εHf(t) values (+13.0 to +14.8), and much younger TDM1 ages (559–484 Ma). This suggests that the primary magma for the andesites was generated by the partial melting of a relatively depleted mantle wedge that was metasomatized by subduction-related fluids. The primary magma for the basalts in the Moguqi area was probably derived from the partial melting of a relatively enriched lithospheric mantle that was also modified by fluids sourced from a subducted slab. These interpretations suggest that the andesites in Duobaoshan formed in a newly accreted island arc setting, whereas the coeval basalts in Moguqi formed along an active continental margin. We therefore attribute the Early–Middle Ordovician volcanism along the eastern margin of the Xing’an Massif to the northwestward subduction of the Nenjiang–Heihe oceanic plate beneath the Xing’an Massif. Furthermore, considering coeval igneous activity in the southern parts of the Xing’an Massif, we suggest that a magmatic arc existed along the margin of the Xing’an Massif in the early Palaeozoic (490–420 Ma). We conclude that the location of the suture between the Xing’an and Songnen–Zhangguangcai Range massifs runs from Airgin Sum, via south of Xilinhot, to Ulanhot, Moguqi, Nenjiang, and finally Heihe.  相似文献   

3.
A combined study of LA-ICP-MS zircon U-Pb dating and geochemical analyses (major and trace elements, and Hf isotopic compositions) for five Permian granitic plutons (Mingyi, Tuoyaozi, Mengjiagang, Hengtoushan, and Qingbei plutons) from the Jiamusi Massif was carried out to determine their ages, petrogenesis, and tectonic evolution. The studied granitic plutons are composed of syengranites, monzogranites, and granodiorites, and they were emplaced in the Early-Middle Permian (278–263 Ma). These granitic plutons are mostly high-K calc-alkaline and weakly peraluminous, and show consistent correlations of different oxides versus SiO2. They are all enriched in large ion lithophile elements (e.g., Rb, Th, K) and light rare earth elements, and depleted in high field strength elements (e.g., Nb, Ta, Ti) and heavy rare earth elements. And they have relatively homogeneous Hf isotopic compositions, with εHf(t) values varying from − 6.16 to + 2.95 and two-stage model ages ranging from 1681 to 1111 Ma. According to their emplacement ages, geochemical characteristics, and Hf isotopic compositions, we conclude that these granitoids might be originated from parental magmas with similar compositions but evolved different degrees of fractionation, and their magmas were derived from the partial melting of amphibolite-facies mafic lower crust. These data, combined with previous studies on contemporaneous magma-tectonic activities in the Jiamusi Massif and Songnen-Zhangguangcai Range Massif, indicate that two paralleled N-S trending Permian magmatic belts are distributed in these two massifs. The eastwards subduction of the Mudanjiang oceanic plate beneath the Jiamusi Massif induced crustal melting to produce the studied Permian N-S trending granitoids in the Jiamusi Massif. Furthermore, westwards subduction of the Mudanjiang oceanic plate beneath the Songnen-Zhangguangcai Range Massif gave rise to Permian magmatism along eastern margin of the Songnen-Zhangguangcai Range Massif. Taken together, we suggest that the Jiamusi Massif and Songnen-Zhangguangcai Range Massif were not collided before the Permian, and a double-side subduction model is favored for the tectonic evolution of the Mudanjiang Ocean during the Permian.  相似文献   

4.
A suite of the fossil-rich marine-land interbedded strata(Nanshuangyashan Formation) is distributed at the eastern margin of the Jiamusi massif in the eastern Heilongjiang Province, NE China. The authors had recently discovered a suite of arkose beneath the marine-land interbedded strata, which overlays unconformably on the Permain granite in the eastern margin of the Jiamusi massif. The LA-ICP-MS zircon U-Pb dating indicate that all detrital zircons from the analysed four arkose samples show the four population ages of 800 Ma, 538–481 Ma, 269–250 Ma and 223–215 Ma. The former three population ages are widely recorded in the Jiamusi-Khanka massif and the Songnen massif. The later group is the minimal age population in the analyzed samples, limiting the sedimentation time of the arkoses occurred after the Late Triassic. At present, the minimal age population is not recorded in the Jiamusi massif, but the granites with the ages of 228–210 Ma are widely distributed in the Songnen-Zhangguangcai Range massif and the Khanka massif. The predominantly Permian zircons are characterized by oscillatory zoning and euhedral shapes, with variable zircon ε_(Hf)(t) values(-5.5 to +11.2), indicating that they were derived from mixture sources, possibly mixed with components of the Songnen-Zhangguangcai Range massif and the Jiamusi-Khanka massif. These results, combined with regional analyses, indicate that the closing of Mudanjiang ocean and Panthalassa ocean possibly existed from Early Permian to Late Triassic.  相似文献   

5.
ABSTRACT

The tectonic affiliation of the Khanka Massif, in the easternmost section of the Central Asian Orogenic Belt (CAOB), is still a matter of debate. Here, we provide new constraints on the provenance and timing of deposition of Permian strata in the western margin of the Khanka Massif. The results, which include U–Pb dating of detrital zircon grains using laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS), provide evidence regarding the tectonic position of the Khanka Massif and its role in the late Palaeozoic evolution of the eastern CAOB. Detrital zircon grains from a sublitharenite (Pingyangzhen Formation), a litharenite (Liangzichuan Formation), and a metamorphic siltstone (Qinglongcun Group) yielded multiple age populations ranging from Neoproterozoic (~914 Ma) to Permian (~272 Ma). Combined with age constraints from overlying/late-stage igneous rocks and other magmatism of the Khanka Massif, we conclude that the dated strata were deposited during the early–middle Permian and were sourced from the Khanka Massif. A comparison between the detrital zircon age populations and the history of magmatic activity in the neighbouring areas suggests that the Khanka Massif was tectonically linked to the Songnen–Zhangguangcai Range Massif. Based on tectonic discrimination diagrams, we conclude that the western margin of the Khanka Massif was positioned in a convergent-boundary basin during the early–middle Permian. Strike-slip faulting along the Dunhua–Mishan Fault, in response to ridge subduction of the Paleo-Asian Ocean Plate, resulted in a north-eastward movement of the Khanka Massif. The occurrence of Precambrian detrital zircon grains (with ages of 1900–1700 and 900–700 Ma) implies the presence of an ancient basement within the Khanka Massif.  相似文献   

6.
This study presents new secondary-ion mass spectrometry (SIMS) rutile and laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS) zircon U-Pb geochronological and whole-rock geochemical data for amphibolites of the Heilongjiang Complex, located within the Yilan area of NE China, to constrain the tectonic evolution of the Mudanjiang Ocean between the Songnen–Zhangguangcai Range and Jiamusi massifs. Magmatic zircon from amphibolites collected from the Yilan Marble Quarry yields a weighted mean 206Pb/238U age of 274 ± 2 Ma, which is interpreted as the protolithic age. Amphibolites from the Longlangang and Tuanshanzi areas yield rutile U-Pb ages of 177 ± 11 Ma and 172 ± 5 Ma, respectively, which are interpreted to reflect the cooling of these rocks below the closure temperature of Pb diffusion in rutile. Amphibolites from the Yilan Marble Quarry are enriched in light rare earth elements (LREEs) and depleted in high field strength elements (HFSEs; e.g., Nb, Ta and P) relative to large ion lithophile elements (LILEs). Amphibolites from the Longlangang and Tuanshanzi areas have relatively flat chondrite-normalized rare earth element (REE) patterns, and remarkable negative Nb and Ta anomalies. Moreover, all of the amphibolites from the Heilongjiang Complex in the Yilan area have tholeiitic and arc-type geochemical affinities. These amphibolites formed by similar petrogenetic processes, but from distinct mantle sources. The magmas that formed these units were generated by the partial melting of mantle sources metasomatized by subducted slab fluids, and the magma that formed the amphibolites within the Yilan Marble Quarry may have also incorporated sedimentary material. Mantle peridotite from the garnet-spinel transition zone is a possible source for the protolith of amphibolites in the Yilan Marble Quarry, and spinel-peridotites may have been the magma sources for the protoliths of amphibolites in the Longlangang and Tuanshanzi areas. Combining our data for amphibolites from the Heilongjiang Complex in the Yilan area with the results of previous research on Late Paleozoic–Early Mesozoic arc magmatism and metamorphism, we infer that the Late Paleozoic–Early Mesozoic tectonic evolution of the Mudanjiang Ocean was characterized by double-sided subduction. These data indicate that the Mudanjiang Ocean closed during the Jurassic (180–160 Ma).  相似文献   

7.
张广才岭是松嫩地块与佳木斯地块之间的碰撞造山带,是东北"巨型花岗岩省"的重要组成部分。本文通过锆石U-Pb定年和岩石地球化学分析,研究了张广才岭南部帽儿山二长花岗岩年代学、地球化学特征和构造背景。锆石U-Pb年代学结果显示:张广才岭南部细粒二长花岗岩成岩年龄为(176.4±1.1)Ma,中粒二长花岗岩成岩年龄为(178.9±1.3)、(177.7±1.1)Ma,粗粒二长花岗岩成岩年龄为(180.0±1.8)、(179.9±1.2)Ma,成岩时代均属于早侏罗世。岩石地球化学研究显示:细粒二长花岗岩、中粒二长花岗岩和粗粒二长花岗岩均具有富硅、贫铝、高碱、低钙,富集Zr、Hf、Rb、K,亏损Ba、Sr、Nb、P、Ti,燕式型稀土配分模式等特征,成岩类型属于造山后A2型花岗岩。结合年代学和地球化学特征,研究区早侏罗世二长花岗岩形成于碰撞后构造背景,代表佳木斯地块和松嫩地块碰撞—拼合过程中的一次伸展作用,表明早侏罗世区域构造环境逐渐由挤压造山向造山后伸展环境转变。  相似文献   

8.
9.
The geological, geochemical, and geochronological data on the granitiods of the Shmakovka massif, which represents a petrotype of the synonymous complex (southern Russian Primorye), show that the granitoid intrusions of the Shmakovka Complex play a “coupling” role, occurring in different blocks of the Khanka composite terrane. The geochemical and isotopic features of the granitoids indicate that their formation resulted from melting of a “mixed,” substantially metapelite, source similar to the most intensely metamorphosed rocks of the Khanka massif. According to U–Pb measurements, the granitoids are 490 ± 1 Ma old. The analysis of the distribution of Early Paleozoic I-, S-, and A-type granitoids in southern Primorye reveals that Late Cambrian–Early Ordovician endogenic events marked the amalgamation of Precambrian–Early Paleozoic blocks and the eventual formation of the Bureya–Jiamusi superterrane (Bureya–Khanka orogenic belt).  相似文献   

10.
朱莹  杨浩  董玉  和越  毕君辉  王智慧  纪政 《世界地质》2017,36(2):413-427
对黑龙江东部依兰珠山变辉长岩进行了锆石年代学和地球化学研究,以确定其形成时代、成因及构造背景。变辉长岩锆石均呈自形-半自形晶,具典型的条痕状吸收特征和较高的Th/U比值(0.20~0.86),暗示其岩浆成因。LA-ICP-MS U-Pb测年结果为(256±3)Ma,表明珠山变辉长岩形成于晚二叠世。地球化学特征显示变辉长岩具有贫硅,富镁、铁、铝、钙的特征;其轻稀土元素(LREEs)和大离子亲石元素(Rb、Ba)富集,重稀土元素(HREEs)和高场强元素(Nb、Ta、Zr、Hf和Ti)亏损。结合区域地质资料,认为珠山变辉长岩为俯冲流体交代地幔楔的产物,其形成可能与古大洋板块的俯冲作用有关,暗示佳木斯地块与松嫩地块在晚二叠世之前尚未碰撞拼合。  相似文献   

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