Lithium isotopic evidence for subduction of the Indian lower crust beneath southern Tibet

Post-collisional K-rich volcanic rocks (KVRs) can provide an opportunity to constrain the architecture of the lithosphere and the mechanisms of plateau uplift. However, their petrogenesis and geodynamic setting remain in dispute. Lithium concentrations and isotopic compositions of 87 potassic, ultrapotassic and Mg-rich potassic volcanic rocks (PVRs, UPVs, and MPRs, respectively) in SW Tibet, along with new Pb–Sr–Nd isotope data and whole-rock analyses, are used to constrain their mantle source and genesis. These rocks are characterized by very similar δ⁷Li values: PVRs vary from −4.9‰ to +3.2‰, UPVs from −3.9‰ to +1.7‰, and MPRs from −1.2‰ to +3.5‰. They can be classified into two groups: Group I (19 out of 87 samples) with heavier δ⁷Li values (+1.0‰ to +3.5‰) similar to those reported for mid-ocean-ridge and ocean-island basalts (MORBs and OIBs, respectively), and Group II (68 out of 87 samples) with lighter values (−4.9‰ to +1.0‰) similar to those of Indian lower crust. These variable isotopic compositions may record the isotopic signature of the early-middle Miocene subcontinental lithospheric mantle (SCLM). This paper demonstrates the existence of isotopically light mantle domains beneath the Lhasa terrane, which were ascribed to the interaction with fluids/melts derived from the subducted Indian lower crust. The modeling curves of Indian lower crust with a metasomatized mantle composition fully account for compositional variations in the PVRs, UPVs, and MPRs. They were generated by the partial melting of SCLM, which was metasomatized by fluids/melts derived from the subducted Indian lower crust (ca. 4–14%, ca. 4–10%, and ca. 6–10% for the PVRs, UPVs, and MPRs, respectively). The Li isotopic data indicate that the Indian lower crust was subducted beneath the central Lhasa subterrane, and this sheds new light on the formation of the Tibet Plateau.     

Subduction of Indian continent beneath southern Tibet in the latest Eocene (~ 35 Ma): Insights from the Quguosha gabbros in southern Lhasa block

Geophysical data illustrate that the Indian continental lithosphere has northward subducted beneath the Tibet Plateau, reaching the Bangong–Nujiang suture in central Tibet. However, when the Indian continental lithosphere started to subduct, and whether the Indian continental crust has injected into the mantle beneath southern Lhasa block, are not clear. Here we report new results from the Quguosha gabbros of southern Lhasa block, southern Tibet. LA-ICP-MS zircon U–Pb dating of two samples gives a ca. 35 Ma formation age (i.e., the latest Eocene) for the Quguosha gabbros. The Quguosha gabbro samples are geochemically characterized by variable SiO₂ and MgO contents, strongly negative Nb–Ta–Ti and slightly negative Eu anomalies, and uniform initial ⁸⁷Sr/⁸⁶Sr (0.7056–0.7058) and ε_Nd(t) (− 2.2 to − 3.6). They exhibit Sr–Nd isotopic compositions different from those of the Jurassic–Eocene magmatic rocks with depleted Sr–Nd isotopic characteristics, but somewhat similar to those of Oligocene–Miocene K-rich magmatic rocks with enriched Sr–Nd isotopic characteristics. We therefore propose that an enriched Indian crustal component was added into the lithospheric mantle beneath southern Lhasa by continental subduction at least prior to the latest Eocene (ca. 35 Ma). We interpret the Quguosha mafic magmas to have been generated by partial melting of lithospheric mantle metasomatized by subducted continental sediments, which entered continental subduction channel(s) and then probably accreted or underplated into the overlying mantle during the northward subduction of the Indian continent. Continental subduction likely played a key role in the formation of the Tibetan plateau at an earlier date than previously thought.     

Crystal-chemistry of clinopyroxenes from potassic and ultrapotassic rocks in central Italy: implications on their genesis

The clinopyroxenes mentioned have been investigated by single crystal X-ray diffraction combined with electron microprobe analysis. The aim of this study was to characterize the crystal-chemical variations of clinopyroxenes in order to delineate the intracrystalline constraints which are characteristic of specific magmatic environments. Clinopyroxenes (cpx) crystallized from peralkaline ultrapotassic melt with kamafugitic and lamproitic affinities are characterized by high Si contents, which are insensitive to variations in silica abundance and silica saturation of the melt. The high Si occupancy in clinopyroxenes from kamafugitic magma is coupled to large M1 (i.e. Mg and Fe²⁺) and M2 (high Ca occupancy) sites, whereas in clinopyroxenes from magmas with lamproitic affinity, high Si content is combined with large M1 but small M2 sites. Clinopyroxenes from Romantype alkaline potassic and ultrapostassic rocks are characterized by an expanded tetrahedron (high ^IVA1 content) and small M1 site which is combined with small M2 polyhedron in clinopyroxenes from the potassic rocks and large M2 site in those from the ultrapotassic rocks.     

Structure of the crust and uppermost mantle beneath southern Finland revealed by analysis of local events registered by the SVEKALAPKO seismic array

In 1998–1999, a large-scale seismic array was deployed in Finland as a part of the EUROPROBE/SVEKALAPKO subproject, involving 14 European universities and research institutes. The objective of the project was to map the deep lithosphere structure and thickness beneath the Fennoscandian Shield by means of teleseismic events. In addition, about 580 local seismic events were registered during the data acquisition period. Among them, only eight local earthquakes were recorded, the rest being quarry blasts from mining sites in Russia, Finland, Estonia and Sweden. In this study, we present the analysis of the seismic wave field from the strongest local events registered by the majority of the stations of the SVEcofennian–KArelian–LAPland–KOla Transect (SVEKALAPKO) array with the aim of mapping the structure of the upper mantle beneath the array. For this purpose, we selected the events corresponding to a single source type and compared these recordings with those from wide-angle reflection and refraction experiments in the area to identify the regional phases. The record sections of selected events demonstrate strong reflections (PmP) from the Moho boundary. The refracted Pn phases can be seen as first arrivals at distances of about 200–400 km from the source. At offsets of about 400–800 km, phases reflected from inhomogeneities in the uppermost mantle (P1) and double reflections from the Moho boundary (PmPPmP) were recorded.Results from 2D forward ray trace modeling of reflected and refracted P-waves along four profile swathes from SVEKALAPKO stations demonstrate that the mantle reflections originate from two different groups of boundaries beneath the array: one group of phases arrive from subhorizontal and gently dipping reflectors below the Moho boundary at a depth of 70–90 km, while the other group are phases originating from a depth of 100 to 130 km. Based on the irregular character of the first group of reflections, their different spatial orientation and correlation with the Moho offsets, we interpret the boundaries of this group as relicts of ancient subduction and collision processes. The second group of reflections can be explained by a transition from mechanically strong to mechanically weak lithosphere.     

The lower crust of the Gangdese magmatic arc,southern Tibet,implication for the growth of continental crust

Magmatic arcs are thought to be the primary sites of modern-day continental crustal growth, and arc crustal sections provide an exceptional opportunity to directly observe the geological processes that occur there, yet few deeply exposed arc sections are available for direct study. The Gangdese magmatic arc, southern Tibet, formed during the Mesozoic subduction of Neo-Tethyan oceanic lithosphere and Cenozoic collision between the Indian and Asian continents, and represent juvenile continental crust. However, the petrological components and compositions of the lower crust of the Gangdese arc remain unknown. Based on detailed geological mapping, we conducted a systemic geochemical, geochronological and zircon Hf isotopic study of well-exposed high-grade metamorphic and migmatitic rocks from the lower crust of the eastern Gangdese arc. The results obtained show that Late Cretaceous garnet amphibolites, dioritic and granitic gneisses, and Paleocene–Eocene garnet amphibolites and granitic gneisses are the main components of the Gangdese lower arc crust. These meta-intrusive rocks witnessed a long period of magmatic, and metamorphic and anatectic processes from the Middle Jurassic to the Late Eocene, and have chemical compositions that range from ultramafic to felsic, with an average SiO₂ content of 57.61 wt% and Mg# value of 0.49. These new data indicate firstly that the Gangdese lower arc crust has an overall intermediate composition and typical feature of juvenile crusts, and therefore supports the recent proposition that continental lower crusts are relatively felsic in composition, instead of mafic. We consider that the downward transport of felsic intrusives and associated sedimentary rocks into the deep crustal levels and subsequent partial melting resulted in componential and compositional changes of the Gangdese arc lower crust over time. This is a potential key mechanism in transforming primary lower arc crust to mature continental lower crust for the magmatic arcs with a complete growth history.     

拉萨地块麻江地区具有“超钾质”成分的钾质火山岩的识别及成因

一般认为青藏高原拉萨地块后碰撞钾质-超钾质岩浆活动由西向东逐渐喷发,然而本文在拉萨地块中部麻江地区识别出一套钾质火山岩,利用单矿物金云母的40Ar-39Ar方法确定其形成于21.3Ma.这套火山岩具有高镁(＞3％)和高钾( K2O/Na2O ＞2)等的超钾质火山岩成分特征,但其高的MgO含量是因岩石中含有后期蚀变矿物白...     

Eocene potassic and ultrapotassic volcanism in south Tibet: New constraints on mantle source characteristics and geodynamic processes

In the Yangbajing area, southern Tibet, several monogenic volcanoes were conformably superimposed on the Linzizong calc-alkaline volcanic successions. According to their petrologic and geochemical characteristics, these monogenic volcanoes are composed of three rock varieties: tephritic phonolitic plugs and shoshonitic and trachytic lavas. Their geochemical systematics reveals that low-pressure evolutionary processes in the large voluminous Linzizong calc-alkaline magmas were not responsible for the generation of these potassic–ultrapotassic rocks, but the significant change in petrologic and geochemical characteristics from the Linzizong calc-alkaline to potassic–ultrapotassic magma is likely accounted for the change of metasomatic agents in the southern Tibetan lithospheric mantle source during the Paleocene to Eocene. The tephritic phonolites containing both leucite and plagioclase show primary ultrapotassic character similar to that of Mediterranean plagioleucititic magmas. Radiogenic Sr increases with SiO₂ in the xenolith-bearing trachytes strongly suggesting significant crustal assimilation in the shoshonitic magmas. The Yangbajing ultrapotassic rocks have high K₂O and Al₂O₃, and show depletion of high field strength elements (HFSEs) with respect to large ion lithophile elements. In primitive mantle-normalized element diagrams, all samples are characterized by positive spikes at Th (U) and Pb with negative anomalies at Ba, Nb–Ta and Ti, reflecting the orogenic nature of the ultrapotassic rocks. They are characterized by highly radiogenic ⁸⁷Sr/⁸⁶Sr_(i) ratios (0.7061–0.7063) and unradiogenic ¹⁴³Nd/¹⁴⁴Nd_(i) (0.5125), and Pb isotopic compositions (²⁰⁶Pb/²⁰⁴Pb = 18.688–18.733, ²⁰⁷Pb/²⁰⁴Pb = 15.613–15.637, and ²⁰⁸Pb/²⁰⁴Pb = 38.861–38.930) similar to the global subducting sediment. Strong enrichment of incompatible trace elements and high Th fractionation from the other HFSEs (such as Nb and U) clearly indicate that the Th-enriched sedimentary component in a network veined mantle source was mainly introduced by sediment-derived melts. In addition, the ultrapotassic rocks have significant Ce (Ce/Ce* = 0.77–0.84) and Eu (Eu/Eu* = 0.72–0.75) anomalies, suggesting a subduction sediment input into the southern Tibetan lithospheric mantle source. In contrast, high U/Th (> 0.20) and Ba/Th (> 32) and low Th/La (< 0.3) in the shoshonites indicate that the Eocene potassic magma originated from partial melting of the surrounding peridotite mantle pervasively affected by slab-related fluid addition from the dehydration of either the subducting oceanic crust or the sediment. Thus, at least two different subduction-related metasomatic agents re-fertilized the upper mantle. According to the radiometric ages and spatial distribution, the Gangdese magmatic association shows a temporal succession from the Linzizong calc-alkaline to ultrapotassic magmas. This indicates a late arrival of recycled sediments within the Tibetan lithospheric mantle wedge. The most diagnostic signatures for the involvement of continent-derived materials are the super-chondritic Zr/Hf (45.5–49.2) and elevated Hf/Sm values (0.81–0.91) in the ultrapotassic rocks. Therefore, the occurrence of orogenic magmatism in the Gangdese belt likely represents the volcanic expression of the onset of the India–Asia collision, preceding the 10 Ma Neo-Tethyan slab break-off process at 42–40 Ma. The absence of residual garnet in the mantle source for the ultrapotassic volcanism seems to imply that the southern Tibetan lithosphere was not been remarkably thickened until the Eocene (～ 50 Ma).     

藏东类乌齐地区古近纪钾质火山岩的发现及特征

古近纪业阿供组火山岩分布于西藏东部类乌齐镇业阿供村,LA-ICP-MS锆石U-Pb年龄为30.54±0.8Ma,岩石具有高碱、低Ti的特征,在SiO2-K2O图解中位于钾质岩区,属于碱性钾质岩。岩石地球化学特征表明,业阿供组钾质火山岩很可能源于古俯冲流体交代的富集地幔源区经过部分熔融作用,形成于碰撞后的板内构造环境。     

松潘地块与西秦岭造山带下地壳的性质和关系——深地震反射剖面的揭露

松潘地块位于青藏高原的东缘,处于中国大陆东西向构造与南北向构造的结合部位,特殊的构造环境使其长期控制并影响着中国大陆的形成与演化。探测松潘地块的岩石圈细结构,揭示其与东昆仑-西秦岭造山带的关系,既可为研究青藏高原东北缘板块碰撞的深部过程奠定基础,同时又关联着松潘地块的油气远景评价。2004年完成了第一条横过松潘地块北缘若尔盖盆地和西秦岭造山带的长约257km的深地震反射剖面,首次揭露出若尔盖盆地和西秦岭造山带岩石圈的细结构。发现若尔盖盆地和西秦岭造山带同属统一的稳定的大陆地块,并且下地壳均以北倾的强反射为主要特征。这种北倾的反射为松潘地块向西秦岭下地壳俯冲提供了地震学证据。近于平坦的Moho反射特征反映出西秦岭造山带在造山后又经历了强烈的伸展作用。     

P-wave tomography and dynamics of the crust and upper mantle beneath western Tibet

The continental collision between the Indian and Asian plates plays a key role in the geologic and tectonic evolution of the Tibetan plateau. In this article we present high-resolution tomographic images of the crust and upper mantle derived from a large number of high-quality seismic data from the ANTILOPE project in western Tibet. Both local and distant earthquakes were used in this study and 35,115 P-wave arrival times were manually picked from the original seismograms. Geological and geochemical results suggested that the subducting Indian plate has reached northward to the Lhasa terrane, whereas our new tomography shows that the Indian plate is currently sub-horizontal and underthrusting to the Jinsha river suture at depths of ~ 100 to ~ 250 km, suggesting that the subduction process has evolved over time. The Asian plate is also imaged clearly from the surface to a depth of ~ 100 km by our tomography, and it is located under the Tarim Basin north of the Altyn Tagh Fault. There is no obvious evidence to show that the Asian plate has subducted beneath western Tibet. The Indian and Asian plates are separated by a prominent low-velocity zone under northern Tibet. We attribute the low-velocity zone to mantle upwelling, which may account for the warm crust and upper mantle beneath that region, and thus explain the different features of magmatism between southern and northern Tibet. But the upwelling may not penetrate through the whole crust. We propose a revised geodynamic model and suggest that the high-velocity zones under Lhasa terrane may reflect a cold crust which has interrupted the crustal flow under the westernmost Tibetan plateau.     

INDEPTH-Ⅲ地震层析成像--藏北印度岩石圈俯冲断落的证据

德庆-龙尾错剖面层析速度结构剖面揭示了在高原地壳发生缩短与增厚后,高速的印度大陆地幔岩石圈分为两层以不同角度向北伸展到(美)塘盆地的中部(33°N~34°N之间).上层在拉萨地块岩石圈(速度为7.9~8.0 km/s)之下向北伸展过程中发生断裂,形成若T断块,并下沉;下层以较大角度向北俯冲下去,并在32°N之下进人软流圈;发现北部有一浅一深2条低速带,可能代表地幔内温度较高的热流体的流动通道,并产生强烈的各向异性.浅处低速带与深部低速带有联系;此低速带与东部Wittlinger发现的34.5°N深部的高温低速体没有直接联系,后者呈NV-SE走向.     

Sr-Nd-Pb isotopic compositions of the lower crust beneath northern Tarim: insights from igneous rocks in the Kuluketage area,NW China

Mineralogy and Petrology - The composition of lower crust of the Tarim Craton in NW China is essential to understand the petrogenesis of the ~290–275&nbsp;Ma Tarim basalts and...     

The post-collisional stabilization of thickened crust in the Southern Urals

The Urals are characterized by a depression of the Moho to a depth of 57 km. This structure is interpreted as a relic orogenic root, which has been conserved because no significant post-collisional processes occurred. However, there is evidence that voluminous post-collisional magmatism affected the lower crust. In this paper, we use thermal finite element models to quantify the influence of the post-collisional magmatism on the stabilization of the root. We show that at least 70% of the heat producing elements migrated in granitic melts from the lower crust to the upper crust. As a result the crustal heat flow reduced and the lithosphere could stabilize at a thickness of 180 km. Furthermore, we propose that a granulite metamorphic event during the thermal relaxation of the collision zone prevented the 57 km thick crust from delamination. These results strongly indicate that post-collisional processes were necessary for the stabilization of the Uralian crust and lithosphere.     

青藏高原北部可可西里地区新生代钾质火山岩地球化学特征及成因

青藏高原北部可可西里地区分布的中新世钾质火山岩(7.77～17.82Ma)主要为粗面安山岩、粗面岩和少量次火山相的流纹斑岩.主量、微量元素及Sr-Nd-Pb同位素地球化学研究表明,该套钾质火山岩强烈富集大离子亲石元素和轻稀土元素,明显亏损Nb-Ta-Ti元素,具有较高的87Sr/86Sr:0.707346～0.714915,较低的εNd值:-3.70～-6.97,和较高的放射性成因Pb同位素组成(207Pb/204Pb=15.65～15.76,208Pb/204Pb=38.98～39.35,206Pb/207Pb=18.67～18.78).上述特征指示岩浆源区可能是与古俯冲消减物质有关的EMⅡ型富集地幔.三大岩类的地球化学成分变异表明:该钾质火山岩系列是富集地幔(金云母-尖晶石二辉橄榄岩和金云母-石榴石二辉橄榄岩)低度部分熔融产生的母岩浆经过较强结晶分异形成的,其中流纹斑岩在岩浆后期可能经历了更为复杂的地壳混染和结晶分异过程.     

Rheological model of the crust beneath southern Sikhote-Alin: Evidence from gravity data

The analysis of the spatial distributions of the density gradients characteristic of spherical sources of gravity anomalies provided grounds for the assessment of the rheological properties of the crust beneath the southern Sikhote-Alin mountainous system, which includes two layers with elevated rigidity and two layers of lowered viscosity. The direct proportional correlation between the rigidity and the density of the modeled mediums is confirmed by solving the direct linear problem of the gravitational potential. The rigid medium is characteristic of the lower crystalline layer of the Amur Plate, the top of which gently dips toward the Sea of Japan coast, and clinoform slabs of the oceanic crust, which underlie the Taukhe and Kema terranes and thrust over the lower layer of the continental crust. The viscous medium corresponds to the subcrustal zone of partial melting beneath the East Sikhote-Alin volcanic belt and to the accretionary complexes of the Samarka and Zhuravlevka terranes, which are involved into shear deformations. The Late Paleozoic and Early Mesozoic geodynamic history of the Sikhote-Alin crust was characterized by the interaction between the continental and oceanic rigid crustal wedges, which determined the directed accretion of the terrigenous turbiditic and island-arc sequences of the marginal sea to the Amur Plate.     

Geochemistry and genesis of ultrapotassic and potassic magmatic rocks on the eastern shore of Chaun Bay in Chukotka and their role in the metallogenic specialization of tin-bearing granitoids

Basite magmatism preceding the intrusion of large volumes of felsic magmas takes place only during powerful tectonic rearrangements, which span both the continental crust and lithospheric mantle. The study of this magmatism makes it possible to solve many genetic problems and obtain important geological information on the sources and processes that are responsible for granitoid magmatism. This paper reports the results of the geochemical study of potassic and ultrapotassic magmatic rocks that predate the intrusion of the granitoid complex and belong to it. In terms of geochemistry, the studied magmatic rocks of Chukotka correspond to the derivatives of potassic and ultrapotassic magmas, which allows us to use the models of formation of ultrapotassic magmas for interpreting the genetic features of tin-bearing granites, in particular, for explaining the anomalous contents of incompatible elements in these rocks. Using modern genetic models in combination with geological, geophysical, and geochemical data, it is established that the source of this specialization was the lithospheric mantle domain. The domain was formed within a convergent geologic boundary owing to the metasomatic reworking of the mantle wedge by fluids that were released during dehydration of the oceanic lithosphere. Based on the obtained results, a new model was proposed for the formation of tin-bearing granitoids in the collisional orogens. This model is underlain by the concept of a particular lithospheric source, which acquired its geochemical and metallogenic signatures during intense tectonic transformation that involved the lithospheric mantle. These signatures were inherited by magmas formed during melting within this domain.     

Catazonal xenoliths in French Neogene volcanic rocks: Constitution of the lower crust

87 samples of granulitic xenoliths scavenged by the Neogene volcanoes in French Massif Central, have been analysed for major elements and Li, Rb, Sr, Ba, V, Cr, Co, Ni, Cu and Zn. These data confirm the presence of rocks with both sedimentary and igneous derivation chemically similar to other granulitic rocks, especially those of the Frazer Range in Australia. Relatively high K and Rb concentration of the metasedimentary rocks conflicts with the hypothesis of systematic depletion of lithophile elements in the lower continental crust.The composition and the elemental variations of the igneous derived rocks suggest a parent magma and a differentiation trend characteristic of tholeiitic rocks. It is proposed that this differentiation was produced at low pressure and consequently, the elemental variation existed before the high pressure granulite facies metamorphism of this series.Although an andesite average of the lower crust (between 25–26 and 12–16 km), directly beneath the Bournac pipe (Velay) is calculated, confirming earlier suggestions of a relatively basic composition but it does not mean that this crust was derived from andesitic rocks.     

冈底斯西段第四纪钾质火山岩的发现及赛利普组的建立

冈底斯西段赛利普一带分布有大面积的钾质火山岩,以前曾被划归上新世一早更新世赛利普群。作者对这套火山岩地层进行了详细野外调查并重新测制了火山岩地层剖面,在该套火山岩下伏及层间湖相碎屑沉积层中获得ESR年龄0．268Ma与0．349Ma。岩石学、岩石化学研究表明,这套火山岩是以安粗质熔岩为主的钾玄岩系列一钾质碱性玄武岩系列火山岩,岩石类型及岩石组合稳定,岩层产状平缓,岩石新鲜,层位相对清楚,故将其命名为赛利普组,属第四纪早一中更新世。这一发现对研究冈底斯构造带新生代以来岩浆活动、构造演化,进而探讨青藏高原隆升机制有着重要的地质意义。     

Amphibole and chlorite in mafic and ultramafic rocks in the lower crust and upper mantle

Stabilities of amphibole and chlorite in mafic and ultramafic compositions have been considered in the model system CaO+MgO+Al₂O₃+SiO₂+H₂O. From topological arguments two petrogenetic grids have been constructed. Although available experimental data in CMASH are compatible with the grid in which amphibole reacts out before chlorite in model ultramafic compositions for the pressure range 6 to 15 kbar, naturally observed mineral assemblages and some experimental data in more complex systems favour the other grid in which chlorite reacts out before amphibole at all pressures. This discrepancy between natural and model systems is due to differential movement of the dehydration equilibria of the two hydrates reflecting the variation of activity of H₂O or of components other than CMASH.     

天然火山作用探测华北下地壳组成、结构及其形成过程

与中上地壳相比，对下地壳组成、结构的认识受限于样品的获取，然而天然火山作用携带的下地壳捕虏体可以为了解下地壳提供关键样品。华北克拉通是世界上最古老的克拉通之一，显生宙以来的火山作用携带有丰富的下地壳捕虏体，为探测华北下地壳组成、结构及其形成过程提供了可能。通过对这些捕虏体定深、定性及定年的综合研究，构建了以信阳，莒南，汉诺坝和女山等典型地区为代表的下地壳组成、结构剖面模型。这些剖面表明，华北克拉通下地壳具有分层的特点，且上老下新，暗示可能与底侵作用有关。其中捕虏体的锆石U- Pb年龄和Hf同位素的研究，揭示了该克拉通下地壳复杂的形成与演化过程：最古老的组成部分可能老至~4. 0 Ga冥古宙，此后经历了3. 80~3. 65 Ga古太古代的再造作用，2. 8~2. 5 Ga 新太古代和2. 3~1. 8 Ga 古元古代的增生与再造共存，同时还经历了显生宙以来包括462~220 Ma，140~90 Ma和47~45 Ma的增生与再造事件。