New age data on the deposits of the Kiselevka-Manoma accretionary complex based on radiolarian fossils

The Kiselevka-Manoma Complex, the youngest accretionary complex in the Russian Far East, is composed of Jurassic-Lower Cretaceous pelagic and hemipelagic oceanic deposits. The radiolarian biostratigraphic study made it possible to refine the stratigraphy of the upper portion of the siliceous sediments from the northeastern fragment of this accretionary complex in the vicinity of the Kiselevka settlement in the Lower Amur region. The transition from pelagic siliceous to hemipelagic siliceous-clayey sedimentation was established within the interval from the Late Barremian to the Middle Aptian in different parts of the complex. The age of the accretion of the oceanic rocks is defined as postmiddle Aptian.     

Stratigraphy and structure of the central East Sakhalin accretionary wedge (Eastern Russia)

The East Sakhalin accretionary wedge is a part of the Cretaceous-Paleogene accretionary system, which developed on the eastern Asian margin in response to subduction of the Pacific oceanic plates. Its formation was related to the evolution of the Early Cretaceous Kem-Samarga island volcanic arc and Late Cretaceous-Paleogene East Sikhote Alin continental-margin volcanic belt. The structure, litho-, and biostratigraphy of the accretionary wedge were investigated in the central part of the East Sakhalin Mountains along two profiles approximately 40 km long crossing the Nabil and Rymnik zones. The general structure of the examined part of the accretionary wedge represents a system of numerous east-vergent tectonic slices. These tectonic slices. tens to hundreds of meters thick. are composed of various siliciclastic rocks, which were formed at the convergent plate boundary, and subordinate oceanic pelagic cherts and basalts, and hemipelagic siliceous and tuffaceous-siliceous mudstones. The siliciclastic deposits include trench-fill mudstones and turbidites and draping sediments. The structure of the accretionary wedge was presumably formed owing to off-scraping and tectonic underplating. The off-scraped and tectonically underplated fragments were probably tectonically juxtaposed along out-of-sequence thrusts with draping deposits. The radiolarian fauna was used to constrain the ages of rocks and time of the accretion episodes in different parts of the accretionary wedge. The defined radiolarian assemblages were correlated with the radiolarian scale for the Tethyan region using the method of unitary associations. In the Nabil zone, the age of pelagic sediments is estimated to have lasted from the Late Jurassic to Early Cretaceous (Barremian); that of hemipelagic sediments, from the early Aptian to middle Albian; and trench-fill and draping deposits of the accretionary complex date back to the middle-late Albian. In the Rymnik zone, the respective ages of cherts, hemipelagic sediments, and trench facies with draping deposits have been determined as Late Jurassic to Early Cretaceous (middle Albian), middle Aptian-middle Cenomanian, and middle-late Cenomanian. East of the rear toward the frontal parts of the accretionary wedge, stratigraphic boundaries between sediments of different lithology become successively younger. Timing of accretion episodes is based on the age of trench-fill and draping sediments of the accretionary wedge. The accretion occurred in a period lasting from the terminal Aptian to the middle Albian in the western part of the Nabil zone and in the middle Cenomanian in the eastern part of the Rymnik zone. The western part of the Nabil zone accreted synchronously with the Kiselevka-Manoma accretionary wedge located westerward on the continent. These accretionary wedges presumably formed along a single convergent plate margin, with the Sakhalin accretionary system located to the south of the Kiselevka-Manoma terrane in the Albian.     

Structure,age, and mechanism of emplacement of the Amur and Kiselevka–Manoma accretionary complexes of the lower Amur region,Russian Far East

The Amur and Kiselevka–Manoma accretionary complexes belong to the Cretaceous Khingan–Okhotsk active continental margin, which was formed in the east of Eurasia as a result of the subduction of the Pacific oceanic plates. The Kiselevka–Manoma complex is composed of oceanic pelagic and hemipelagic sedimentary rocks and intraplate oceanic basalts. It is located to the southeast, along the ocean-faced front of the Amur complex, which is predominantly composed of turbidites of the convergent boundary of lithospheric plates. The biostratigraphic study of radiolarians from rocks of the frontal part of the Amur complex allowed us to correlate them with rocks of the Kiselevka–Manoma complex and to define the period of accretion to be from the Late Aptian to the Middle Albian. The tectonostratigraphic interrelations of these two contrasting lithotectonic complexes are established and two possible models of their common emplacement are suggested. Both models suppose a continuous spatiotemporal relation of complexes with the primary paleolocation of the Kiselevka–Manoma complex in front of (on the ocean side) the Amur complex. The frontal part of the Amur complex and the Kiselevka–Manoma complex were emplaced synchronously with the western part of the East Sakhalin accretionary complex. This scenario defines the Early Cretaceous tectonic zonation of the region and the choice of the appropriate paleotectonic model. At the end of the Early Cretaceous, a single convergent boundary of the lithospheric plates is suggested with the position of the Sakhalin island arc system south of the Khingan–Okhotsk active continental margin.     

Ocean Plate Stratigraphy in East and Southeast Asia

Ancient accretionary wedges have been recognised by the presence of glaucophane schist, radiolarian chert and mélange. Recent techniques for the reconstruction of disrupted fragments of such wedges by means of radiolarian biostratigraphy, provide a more comprehensive history of ocean plate subduction and successive accretion of ocean floor materials from the oceanic plate through offscraping and underplating.Reconstructed ocean floor sequences found in ancient accretionary complexes in Japan comprise, from oldest to youngest, pillow basalt, limestone, radiolarian chert, siliceous shale, and shale and sandstone. Similar lithologies also occur in the mélange complexes of the Philippines, Indonesia, Thailand and other regions. This succession is called ‘Ocean Plate Stratigraphy’ (OPS), and it represents the following sequence of processes: birth of the oceanic plate at the oceanic ridge; formation of volcanic islands near the ridge, covered by calcareous reefs; sedimentation of calcilutite on the flanks of the volcanic islands where radiolarian chert is also deposited; deposition of radiolarian skeletons on the oceanic plate in a pelagic setting, and sedimentary mixing of radiolarian remains and detrital grains to form siliceous shale in a hemipelagic setting; and sedimentation of coarse-grained sandstone and shale at or near the trench of the convergent margin.Radiolarian biostratigraphy of detrital sedimentary rocks provides information on the time and duration of ocean plate subduction. The ages of detrital sediments becomes younger oceanward as younger packages of OPS are scraped off the downgoing plate.OPS reconstructed from ancient accretionary complexes give us the age of subduction and accretion, direction of subduction, and ancient tectonic environments and is an important key to understanding the paleoenvironment and history of the paleo-oceans now represented only in suture zones and orogenic belts.     

浙黔桂地区寒武纪硅质岩的地球化学特征及其形成背景

本文采用常量和稀土元素地球化学方法对浙黔桂地区寒武纪硅质岩的形成背景进行了研究。研究表明,硅质岩的A12O3/（A12O3＋Fe2O3）为0.56~0.87;Ce/Ce＊为0.74±0.19;Lan/Cen为0.90~1.58;Lan/Ybn平均为6.38,轻稀土明显富集,这些特征表明研究区硅质岩形成于大陆边缘环境或大陆边缘与深海过渡带。形成于裂陷盆地初期的硅质岩,比古华南残留洋盆和扬子陆块边缘的硅质岩轻稀土元素更加富集。构造拉张期形成的硅质岩为热液成因硅质岩,其稀土配分模式显示出轻稀土相对亏损、Eu正异常特征;构造稳定期形成的硅质岩为沉积成因硅质岩,稀土配分模式显示出轻稀土相对富集、Eu弱负异常特征。由硅质岩稀土配分模式的差异性反映出寒武纪时期的拉张为幕式拉张。位于扬子地台边缘的硅质岩所具有的Ce负异常,暗示着江南造山带寒武纪后曾发生过由东向西的大规模逆冲推覆。     

秦岭早古生代沉积作用与构造演化

根据对秦岭及其两侧地台区沉积体系与旋回沉积的分析，认为该区在早古生代总体上处于板块的扩张阶段，其中巨厚的台地碳酸盐岩的广布的远洋沉积是其典型岩相。早奥陶世阿伦尼克中期华北地台南的一度隆升与剥蚀，标志着俯冲作用开始，但未发现加里东期碰撞造山作用的证据。该区晚奥陶世一志留纪大规模的海退主要是全球海平面下降的结果，与碰撞造山人关系不大。     

赣东北地区不同时代硅质岩的地球化学特征及其地质意义

赣东北地区硅质岩各时代均有不同程度的发育,各时代硅质岩的SiO2含量变化范围为74．90％～97．19％,Si／Al为10．84～93．21,与Al2O3呈较好的负相关关系,表明它们含有较高比例的陆源泥质沉积物,硅质岩样品的Al2O3／(Al2O3+F2O3)=0．60～0．99,Ce／Ce=0．99～1．22,(La／Ce)N=0．91～1．83,V／Y<5．78,Ti／V>17。上述特征表明本区硅质岩形成于大陆边缘构造环境,而与大洋盆地及洋中脊构造环境无关。自古生代以来,该地区没有出现深海大洋盆地环境。     

OCEANIC DEPOSITS IN THE YARLUNG—TSANGPO SUTURE ZONE: STRUCTURAL SETTING, RADIOLARIAN AGES AND THEIR TECTONIC IMPLICATIONS

OCEANIC DEPOSITS IN THE YARLUNG—TSANGPO SUTURE ZONE: STRUCTURAL SETTING, RADIOLARIAN AGES AND THEIR TECTONIC IMPLICATIONS     

西藏冈底斯带石炭纪—二叠纪岛弧造山作用：火山岩及地球化学证据

系统研究了西藏冈底斯带石炭纪—二叠纪火山岩的时空分布、岩相学、元素及Sr、Nd、Pb 同位素地球化学和构造环境、源区性质,并与喜马拉雅带二叠纪火山岩进行了对比研究。冈底斯带石炭纪—二叠纪火山岩近东西向集中分布在冈底斯构造带中北部地带,空间上从东至西火山活动的强度和规模渐次减小,时间上从早至晚火山活动的强度和规模总体由弱到强。冈底斯带石炭纪—二叠纪火山岩形成于活动大陆边缘的岛弧构造环境,从早到晚岛弧造山作用经历了初始岛弧→早期岛弧→成熟岛弧的发展演变过程,火山岩浆来源于富集型地幔部分熔融作用,原始岩浆在形成和演化的过程中有俯冲洋壳及随带的深海沉积物和再循环进人地慢的地壳物质组分的强烈混染,明显不同于受地壳物质组分强烈混染的喜马拉雅带二叠纪陆缘裂陷型火山岩。综合研究冈底斯带及其邻区近年来的最新调查与研究成果,从北向南拟建了石炭纪—二叠纪冈底斯岛弧→雅鲁藏布江弧后裂谷盆地→喜马拉雅陆缘裂陷盆地的弧盆系时空结构演化模式,探讨了冈瓦纳大陆北缘石炭纪—二叠纪活动大陆边缘的岛弧造山作用与青藏高原古特提斯演化的耦合关系及其动力学机制,讨论了冈底斯带松多乡榴辉岩的形成过程。     

Upper Silurian and Devonian pelagic deep-water radiolarian chert from the Khangai–Khentei belt of Central Mongolia: Evidence for Middle Paleozoic subduction–accretion activity in the Central Asian Orogenic Belt

Recent mapping projects undertaken in Central Mongolia have revealed the widespread occurrence of radiolarian chert within a Paleozoic accretionary complex. We present the results of the first detailed tectonostratigraphic and radiolarian biostratigraphic investigations of the Gorkhi Formation in the Khangai–Khentei belt of the Central Asian Orogenic Belt.The Gorkhi Formation consists of sandstone shale, alternating sandstone and shale of turbidite affinity and chert with small amounts of siliceous shale, basalt, limestone, and clast-bearing mudstone. Radiolarian chert that is completely devoid of terrigenous clastic material is commonly associated with underlying basalt (sedimentary contact) and with conformably overlying siliceous shale and turbidite deposits. The tectonic stacking of basalt–chert and chert–turbidite successions is the most remarkable structural feature of the formation.The recovery of moderately well-preserved radiolarians and conodonts from red chert led to the recognition of four radiolarian assemblages that have a combined age range from the latest Silurian (Pridolian) to the Late Devonian (Frasnian). No age control exists for the siliceous shale, shale, and sandstone, although they are considered to be latest Devonian or slightly younger on the basis of stratigraphic relationships with underlying chert.The Gorkhi Formation has previously been interpreted as a thick sedimentary basin deposit overlying an unexposed Archean–Neoproterozoic basement; however, the stratigraphy within individual tectonic slices clearly corresponds to that of an ocean plate stratigraphy of an accretionary complex generated by the trenchward movement of an oceanic plate. From the lowermost to uppermost units, the stratigraphy comprises ocean floor basalt, pelagic deep-water radiolarian chert, hemipelagic siliceous shale, and terrigenous turbidite deposits. The biostratigraphic data obtained in the present study provide corroborating evidence for the existence of an extensive deep-water ocean that enabled the continuous sedimentation of pelagic chert over a period of nearly 50 million years. These data, together with structural data characterized by tectonic repetition of the stratigraphy, indicate that these rocks formed as an accretionary wedge along an active continental margin, possibly that of the Angara Craton. The mid-oceanic chert was probably deposited in the Northern Hemisphere portion of the Paleo–Pacific Ocean that faced the Angara Craton and the North China–Tarim blocks. Thus, we propose that subduction–accretion processes along the Paleo–Pacific rim played an important role in the accretionary growth of the active continental margin of the Angara Craton, directly influencing the evolution of the Central Asian Orogenic Belt.     

大陆中洋壳俯冲增生杂岩带特征与识别的重大科学意义

大洋或弧后洋盆俯冲增生是大陆地壳增长的主导地质作用.重建大陆中消亡的洋地层岩石组合序列是当代大陆动力学和地学研究的重大前沿.洋壳消减杂岩带的厘定是洋板块地质构造重建乃至全球大地构造研究之纲,是理解区域大地构造形成演化及动力学的核心.俯冲增生杂岩带的基本特征:(1)俯冲增生杂岩带物质组成的共性是:以强烈构造变形洋底沉积的硅质岩-硅泥质岩-粉砂岩、凝灰岩;弧-沟浊积岩等为基质;以洋岛-海山灰岩-玄武岩及塌积砾岩,洋内弧残留岩块,超镁铁质蛇绿岩、绿片岩、蓝片岩等为岩块.(2)变形样式:同斜倒转冲断叠瓦构造、增生柱前缘重力滑动构造以及泥质岩的底辟构造;增生楔前缘变形和增生形式受控于大洋或弧后洋盆的规模和洋壳的俯冲速度,也取决于陆缘碎屑供给量及洋底沉积厚度和岩性.(3)宽度和厚度:厚常达几千米,宽达几十公里至数百公里,延长上千公里,是洋壳俯冲消亡过程洋盆地层系统及陆缘沉积物加积的结果.(4)形成机制:是大陆碰撞前大洋(或弧后洋盆)岩石圈俯冲消减的产物.结合带中的早期俯冲增生杂岩带往往卷入晚期的构造混杂作用.     

Chemical composition of the bottom sediments in the middle reaches of the Amur River

The chemical composition of the bottom sediments of the Amur River has been analyzed using modern analytical techniques. It was found that their composition and distribution patterns are controlled by several sources. The most probable sources for the bottom sediments of the studied area are siliceous magmatic or metasedimentary rocks.     

Sedimentary characteristics and provenance of the basal conglomerate of the Late Jurassic-Early Cretaceous Jiaolai Basin,eastern China and their implications for the uplift of the Sulu Orogenic Belt

ABSTRACT

The basal conglomerates (‘Linsishan Conglomerate’, LC, herein) are exposed discontinuously along the northern part of the Sulu Orogenic Belt (SOB) and the southern part of the Jiaobei Terrane. Studying these conglomerates can offer key constrains for the formation age of the Jiaolai Basin and improve our understanding of the uplift and erosional histories of the SOB and Jiaobei Terrane, which are still in great controversy. In Huangyadi section, the LC is characterized as debris-flow deposits, channel deposits, and sheet-flow deposits. However, in Shanjiao section, the LC is changed to sheet-flow and sieve deposits, as well as debris-flow and channel deposits. These deposit characteristics indicate an unstable tectonic setting during initial opening stage of the basin. Based on the data of conglomerate component, palaeocurrent, and debris zircons ages, it can be inferred that the sediments in the Laiyang region were sourced from the Jiaobei Terrane and Northern Sulu Orogenic Belt (NSOB), and the sediments in the Zhucheng and Wulian regions were derived from the Jiaobei Terrane and the Southern Sulu Orogenic Belt (SSOB). Besides, the sediments in the Haiyang and Jimo regions were provided by the NSOB and SSOB, respectively. The significant SHRIMP U–Pb ages of a tuff developing in the LC has been obtained, indicating that 149 ± 2.5 Ma is the oldest age constraint for the Jiaolai Basin. In addition, our result shows that the Latest Jurassic (ca. 149 Ma) may be a critical time; before this time, the Jiaobei Terrane and the SOB experienced a rapid uplift with minimal uplift velocity (~0.9 km/Ma); since then, the Orogen began to collapse and a series of basins formed rapidly in its core, which indicate the tectonic stress regime of the Dabie-Sulu Orogen varied from compressional stress to tensile stress.     

Structured serpentinite melanges of the Koryak-Kamchatka fold system

The Kuyul, Taigonos, and Upper Khatyrka structured serpentinite melanges at the Pacific continental margin of Northeast Asia considered in this paper are diverse in tectonic setting, age, and geological history. They are characterized by an ordered internal structure expressed in regular arrangement of rock blocks different in composition. These blocks make up mappable tectonic sheets deformed into complex, nappe-related folds. Difference in the block composition of particular sheets is often combined with different composition of serpentinite matrix. The structured melanges of Cape Povorotny (Taigonos Peninsula) and the Kuyul Terrane were formed during accretion of oceanic complexes to a suprasubduction zone and their subsequent juxtaposition. The Upper Khatyrka melange comprises oceanic, island-arc, and marginal-sea complexes. The study of structured melanges makes it possible to ascertain the history of continental accretion and transformation of the oceanic crust. The combination of ordering and chaotic structure allows us to consider structured melanges as manifestations of nonlinear geodynamics.     

秦岭勉略缝合带组成与古洋盆演化

秦岭勉略构造带是典型的蛇绿构造混杂岩带,带内组成复杂、变形强烈,其主导构造样式表现为以系列北倾逆冲断层为格架,不同岩片推覆叠置的叠瓦状构造。详细的组成及构造研究表明,缝合带由洋盆形成演化不同阶段、不同性质的陆缘沉积岩系、不同类型蛇绿岩以及洋盆俯冲－碰撞造山过程中以不同方式出露的构造岩块组成,同时区域地层对比表明勉略古洋盆形成过程具有自西而东“剪刀式”打开扩展的性质与特点。     

Present-day tectonics of the western part of the Dzhugdzhur–Stanovoi Terrane of the southeastern frame of the North Asian Craton

The first results on current movements are presented for the western part of the Dzhugdzhur–Stanovoi Terrane based on GPS geodesy of a geodynamic survey area of the Upper Amur region. Processing of the GPS data resulted in a vector field of the displacement rates of points of the geodynamic survey area with zones of intense deformations. It was concluded from a comprehensive analysis of geological–geophysical data and estimates of the displacement rates that the terrane is characterized by kinematic integrity and was subjected to a complex of tectonic factors related to the evolution of the eastern segment of Baikal Rift Zone in the area of transpression interaction of the Eurasian and Amur plates.     

滇西北金沙江带硅质岩沉积环境的确定及大地构造意义

硅质岩是金沙造山带中广泛分布的一种岩石类型，其沉积环境的确定对金沙江造山带的深海沉积、大陆边缘地质以及构造格局等方面的研究具有重要意义。本文从岩性特征、放射虫生态组合特征、稀土元素地球化学特征以及沉积组合特征等方面对滇西北金沙江带硅质沉积环境进行了综合研究，据此认为金沙江缝合带不能构成古特提斯域的主缝合带。     

New data on the Vrancea Nappe (Moldavidian Basin, Outer Carpathian Domain, Romania): paleogeographic and geodynamic reconstructions

A study has been performed on the Cretaceous to Early Miocene succession of the Vrancea Nappe (Outer Carpathians, Romania), based on field reconstruction of the stratigraphic record, mineralogical-petrographic and geochemical analyses. Extra-basinal clastic supply and intra-basinal autochthonous deposits have been differentiated, appearing laterally inter-fingered and/or interbedded. The main clastic petrofacies consist of calcarenites, sub-litharenites, quartzarenites, sub-arkoses, and polygenic conglomerates derived from extra-basinal margins. An alternate internal and external provenance of the different supplies is the result of the paleogeographic re-organization of the basin/margins system due to tectonic activation and exhumation of rising areas. The intra-basinal deposits consist of black shales and siliceous sediments (silexites and cherty beds), evidencing major environmental changes in the Moldavidian Basin. Organic-matter-rich black shales were deposited during anoxic episodes related to sediment starvation and high nutrient influx due to paleogeographic isolation of the basin caused by plate drifting. The black shales display relatively high contents in sub-mature to mature, Type II lipidic organic matter (good oil and gas-prone source rocks) constituting a potentially active petroleum system. The intra-basinal siliceous sediments are related to oxic pelagic or hemipelagic environments under tectonic quiescence conditions although its increase in the Oligocene part of the succession can be correlated with volcanic supplies. The integration of all the data in the “progressive reorientation of convergence direction” Carpathian model, and their consideration in the framework of a foreland basin, led to propose some constrains on the paleogeographic-geodynamic evolutionary model of the Moldavidian Basin from the Late Cretaceous to the Burdigalian.     

The Late Riphean–Paleozoic history of the Uda–Vitim island arc system in the Transbaikalian sector of the Paleoasian ocean

New structural, petrological, chemical, isotope, and paleomagnetic data have provided clues to the Late Riphean–Paleozoic history of the Uda–Vitim island arc system (UVIAS) in the Transbaikalian sector of the Paleoasian ocean, as part of the Transbaikalian zone of Paleozoids. The island arc system consists of three units corresponding to main evolution stages: (i) Upper Riphean (Late Baikalian), (ii) Vendian–Lower Paleozoic (Caledonian), and (iii) Middle–Upper Paleozoic (Hercynian). The earliest stage produced the base of the system composed of Late Riphean ophiolite (971–892 Ma, U-Pb) and volcanic (837–789 Ma, U-Pb) and sedimentary rocks (hemipelagic siliceous sediments and dolerite sills) which represent the Barguzin–Vitim oceanic basin and the Kelyana island arc. The main event of the second stage was the formation of the large UVIAS structure (over 150,000 km2) which comprised the Transbaikalian oceanic basin, the forearc and backarc basins, and the volcanic arc itself, and consisted of many volcanic-tectonic units exceeding 100 km² in area (Eravna, Oldynda, Abaga, etc.). Lithology, stratigraphy, major–element compositions, and isotope ages of Vendian–Cambrian volcanic rocks and associated sediments indicate strong differentiation of calc-alkaline series and the origin of the island arc system upon oceanic crust, in a setting similar to that of the today’s Kuriles–Kamchatka island arc system. The Middle–Upper Paleozoic stage completed the long UVIAS history and left its imprint in sedimentary and volcanic rocks in superposed trough basins. The rocks were studied in terms of their biostratigraphic and isotope age constraints, as well as major- and trace-element compositions, and were interpreted as products of weathering and tectonic-magmatic rework of the UVIAS units.     

Marginal accretion processes of Jiamusi Block in NE China: Evidences from detrital zircon U-Pb age and deformation of the Wandashan Terrane

The eastern segment of Central Asian Orogenic Belt underwent not only a long evolution history related to the Paleo-Asian Ocean during Paleozoic but also the tectonic overprinting by the westward subduction of Paleo-Pacific Ocean crust during Mesozoic. When the subduction of Paleo-Pacific Ocean crust started has been long debated issue for understanding the tectonic evolution of the eastern Asian continental margin. The eastern margin of the Jimusi Block (Wandashan Terrane) preserved complete records for the accretionary process of the westward subduction of Paleo-Pacific Ocean crust. Comprising the Yuejinshan Complex and Raohe Accretionary Complex (RAC), the Wandashan Terrane is located in the eastern margin of Jiamusi Block, NE China, and is considered to be an accretionary wedge of the westward subducting oceanic crust. To reconstruct the marginal accretion processes of the Jiamusi Block, the structural deformation of the Wandashan Terrane was investigated in the field and the geochronology of the Dalingqiao and Yongfuqiao formations were studied, which were formed syn-and-post RAC accretion respectively. The Yuejinshan and Raohe complexes were discontinuously accreted to the eastern margin of the Jiamusi Block. Contrary to the previous consideration of the Late Triassic to Early Jurassic, this study suggests that the Yuejianshan Complex in southwest Wandashan Terrane probably accreted from Late Carboniferous to Middle Permian, which was driven by unknown oceanic crust subduction existing to the east (present position) of the Jiamusi Block at that time. The siltstones of the Dalingqiao Fm. yield the youngest zircon U-Pb age of 142 ± 2 Ma, indicating the emplacement of the RAC not earlier than the Late Jurassic. Thus, the RAC might start to accrete from the Jurassic and emplace during 142–131 Ma, resulted from the Paleo-Pacific subduction which started from the Late Triassic to Early Jurassic.