中国大陆地壳“镶嵌与叠覆”的结构特征及其演化

初步探讨了中国大陆地壳“块带镶嵌多层叠覆”的结构特征和多阶段的构造演化过程。中国大陆地壳新元古代中期以来的一级构造单元有中朝、塔里木、扬子、敦煌4个陆块和中央、西北、东北、西南、东南5个造山区(带)。中朝陆块的形成源于古元古代期间发生的古大陆裂解;扬子、塔里木和敦煌陆块的形成源于新元古代早期发生的古大陆裂解。西北造山区的形成源于古生代晚期洋盆关闭、大陆碰撞并叠加新生代陆内再造山;东北造山带的形成过程包括古生代碰撞造山及中生代增生、碰撞造山;中央造山带至三叠纪大陆碰撞才最后形成并叠加有新生代再造山;东南造山带的形成经历了古生代至新生代的多次造山作用;西南造山带主要是中—新生代造山作用的产物。这些单元都具有“块带镶嵌多层叠覆”的结构特征和多阶段构造演化的特点。中国大陆地壳的形成与演化可以划分为太古宙—古元古代、中元古代—新元古代早期、新元古代中期—古新世和始新世以来4个构造阶段,每个阶段都对应不同的超大陆裂解-聚合旋回。其中新元古代中期以来的地壳形成演化与全球洋陆格局中的古亚洲洋、古特提斯洋、古太平洋、特提斯洋和太平洋5个动力学体制有关,相应地可以归结为古亚洲、古特提斯、古太平洋、特提斯和太平洋5个造山域。正是这些多阶段的超大     

克拉通演化的超大陆背景与克拉通盆地的成因机制

研究表明克拉通的形成与超大陆的汇聚和裂解有着重要关系。本文对近年来超大陆重建的研究进行了分析对比,对克拉通发展与超大陆事件的关系做出了总结。前人对超大陆的研究表明,其形成与地幔动力有直接联系,地幔柱重组的旋回导致了超大陆的旋回。Phillips and Bunge（2007）在前人三维球体地幔对流模型的基础上加入大陆进行了模拟实验,结果显示周期性的超大陆旋回只发生在理想模型中,而Senshu et al.（2009）对代表陆壳的英云闪长岩-奥长花岗岩-花岗岩（TTG）地壳进行了研究,提出随着俯冲的TTG地壳产热速率的下降,超大陆旋回的周期随之变长;更有许多学者指出,历史上哥伦比亚超大陆存在时间明显较长,因此超大陆的旋回并不具有周期性。对近年来不同学者提出的哥伦比亚、 罗迪尼亚、 冈瓦纳、 潘基亚4个超大陆新的重建证据进行分析,大致确定出上述4个超大陆的形成时间、 格局及演化过程。此外,对华北、 东欧、 西伯利亚、 亚马孙、 刚果、 西非6个克拉通各自的演化进行分析,也显示出克拉通演化与超大陆汇聚及裂解在时间与空间上有对应关系。通过分析得出克拉通演化与超大陆旋回有关,且确定出克拉通演化的4个超大陆旋回。本文最后讨论了克拉通盆地的成因机制以及3种端元类型,并将盆地的发育与超大陆演化的巨旋回相联系。     

Metallogenic specialization of supercontinent cycles: A case study of silver deposits

The distribution of integrated resources of large and superlarge mineral deposits (LSLDs) of silver, where the main part of industrially recoverable silver reserves is concentrated, is compared with the existing model of supercontinent cyclicity over the geological history of the Earth. It is found that each supercontinent cycle (Kenoran, Columbian, Rodinian, Pangean, and Amasian) is particularly expressed in the silver metallogeny. The significant intercycle variations in the numbers of LSLDs, diversity of types of these deposits, accumulated resources, mean tenors of silver in ores, and some other numerically expressible characteristics are revealed. These variations correlate with a number of geohistorical changes in the conditions under which endogenous and exogenous geological processes run.     

Influence of supercontinent cyclicity on global metallogenic processes: Main tendencies

The distribution of large and superlarge mineral deposits (LSMD) of the most important raw materials is correlated with supercontinent cycles in the geological history of the Earth. The latter displays the distinct correlation between metallogenic activity and cyclic global endogenous processes reflected in quasi-regular cycles, which result eventually in the assembly and breakup of supercontinents. In the framework of these cycles, the maximums in the LSMD assembly coincide with periods of intense growth of the subcontinent crust owing to growth of the matter originated from juvenile sources (Kenoran, Columbian cycles) or with epochs of intense recycling of the mature crust (Pangean, Amasian cycles). The Rodinian cycle with minimum activity of these both endogenous processes demonstrates simultaneously minimum metallogenic activity. The distribution of most LSMD types generally follows these main tendencies.     

Continental Growth During Formation of Rodinia at 1.35-0.9 Ga

Nd isotopic data and U/Pb zircon ages suggest that only 7–13% of continental crust was formed between 1.35 to 0.9 Ga. Calculated crustal production rates during this time fall within the 1.1 km³/y average production rate of continental crust. This distribution of juvenile continental crust supports the existence of only two major superplume events at 2.7 and 1.9 Ga, and one or two minor events in the Phanerozoic at about 300 and 110 Ma. The absence of a 1.35-0.9 Ga juvenile crust peak may be related to supercontinent history. Results of this study confirm that although both the supercontinent and superplume cycles are episodic, each cycle can operate independently of the other.     

华北地块北缘中新元古界沉积构造演化

根据文献资料及对研究区8 条实测剖面资料的综合分析结果表明,Columbia 超级大陆的裂解导致华北陆块北缘大陆裂 谷盆地的形成。随着大陆进一步伸展和洋壳的形成,华北地块北缘逐渐发展为被动大陆边缘。在1400 Ma 左右,即铁岭组 沉积后,华北地块北缘转变为活动大陆边缘。早期洋壳向华北地块低角度的俯冲造成弧后地区发生挤压（芹峪上升）,导致 铁岭组抬升和剥蚀,而后期洋壳高角度的俯冲又造成弧后区域发生强烈的伸展和断陷,沉积了下马岭组,并伴随辉绿岩的 侵入。华北地块与相邻地体之间的碰撞导致下马岭组的抬升（或蔚县抬升）以及碰撞花岗岩的形成,挤压构造发生的时间 对应于Rodinia 超级大陆的形成期。新元古代沉积是Rodinia 超级大陆裂解的结果。龙山组石英砂岩和海绿石砂岩是Rodinia 超级大陆裂解后的最早期沉积,记录了海侵初期的超覆过程。     

The boring billion? – Lid tectonics, continental growth and environmental change associated with the Columbia supercontinent

The evolution of Earth＇s biosphere,atmosphere and hydrosphere is tied to the formation of continental crust and its subsequent movements on tectonic plates.The supercontinent cycle posits that the continental crust is periodically amalgamated into a single landmass,subsequently breaking up and dispersing into various continental fragments.Columbia is possibly the first true supercontinent,it amalgamated during the 2.0-1.7 Ga period,and collisional orogenesis resulting from its formation peaked at 1.95-1.85 Ga.Geological and palaeomagnetic evidence indicate that Columbia remained as a quasi-integral continental lid until at least 1.3 Ga.Numerous break-up attempts are evidenced by dyke swarms with a large temporal and spatial range; however,palaeomagnetic and geologic evidence suggest these attempts remained unsuccessful.Rather than dispersing into continental fragments,the Columbia supercontinent underwent only minor modifications to form the next supercontinent （Rodinia） at 1.1 -0.9 Ga; these included the transformation of external accretionary belts into the internal Grenville and equivalent collisional belts.Although Columbia provides evidence for a form of ‘lid tectonics’,modern style plate tectonics occurred on its periphery in the form of accretionary orogens.The detrital zircon and preserved geological record are compatible with an increase in the volume of continental crust during Columbia＇s lifespan; this is a consequence of the continuous accretionary processes along its margins.The quiescence in plate tectonic movements during Columbia＇s lifespan is correlative with a long period of stability in Earth＇s atmospheric and oceanic chemistry.Increased variability starting at 1.3 Ga in the environmental record coincides with the transformation of Columbia to Rodinia; thus,the link between plate tectonics and environmental change is strengthened with this interpretation of supercontinent history.     

The making and breaking of supercontinents: Some speculations based on superplumes, super downwelling and the role of tectosphere

The mechanisms of formation and disruption of supercontinents have been topics of debate. Based on the Y-shaped topology, we identify two major types of subduction zones on the globe: the Circum-Pacific subduction zone and the Tethyan subduction zone. We propose that the process of formation of supercontinents is controlled by super downwelling that develops through double-sided subduction zones as seen in the present day western Pacific, and also as endorsed by both geologic history and P-wave whole mantle tomography. The super-downwelling swallows all material like a black hole in the outer space, pulling together continents into a tight assembly. The fate of supercontinents is dictated by superplumes (super-upwelling) which break apart the continental assemblies. We evaluate the configuration of major supercontinents through Earth history and propose the tectonic framework leading to the future supercontinent Amasia 250 million years from present, with the present day Western Pacific region as its frontier. We propose that the tectosphere which functions as the buoyant keel of continental crust plays a crucial role in the supercontinental cycle, including continental fragmentation, dispersion and amalgamation. The continental crust is generally very thin, only about one tenth of the thickness of the tectosphere. If the rigidity and buoyancy is derived from the tectosphere, with the granitic upper crust playing only a negligible role, then supercontinent cycle may reflect the dispersion and amalgamation of the tectosphere. Therefore, supercontinent cycle may correspond to super-tectosphere cycle.     

Significance of age periodicity in the continental crust record: The São Francisco Craton and adjacent Neoproterozoic orogens as a case study

The São Francisco Craton, in Brazil, together with adjacent orogenic systems formed during Gondwana assemblage, are well-suited for the study of crustal growth processes. The region's geological history is marked by a series of complete tectono-metamorphic cycles, from the Archean to late Neoproterozoic, comprising arc-related magmatism followed by continental collisions and ultimately post-tectonic igneous events and rifting. In this contribution, a comprehensive isotopic database was compiled from the literature, composed mainly of high-quality U-Pb magmatic and metamorphic ages (ca. 1000), together with Lu-Hf (ca. 1300) and Sm-Nd (ca. 300) data. Using this database, combined with a tectonic/geochemical synthesized review of the region, it is possible to test which of the available contending models can better explain the apparent periodicity in the formation of the continental crustal. Some interpreted the peaks and troughs in the crustal age record as periods of increased magmatic production, controlled by periodic mantellic events. Another hypothesis is that subduction-related rocks are shielded from tectonic erosion after continental amalgamation, the peaks thus reflecting enhanced preservation potential. The latter hypothesis is favored, as the variability regarding the timing of arc-related peak magmatic production (U-Pb age peaks) from different tectonic provinces around the globe and in the considered regions, coupled to the fact that peak arc-production is always closely followed in time by major continental amalgamations (supercontinent formation), precludes a unified global causation effect, such as mantellic overturns or slab avalanches, and supports the preservation bias hypothesis. Furthermore, the worldwide (including the São Francisco Craton) occurrence of plume-related magmatism is concentrated during the periods of supercontinent break-up (i.e. after major collisions), which better relates to a top-down control on mantle convection and opposes most of the models that advocate for the primary periodicity of magmatic production, which predict enhanced plume activity slightly prior or concomitant to supercontinent formation events.     

Asia: a frontier for a future supercontinent Amasia

Asia is the world’s largest but youngest continent, in which Pacific-type (P-type) and collision-type (C-type) orogenic belts coexist with numerous amalgamated continental blocks. P-type orogens represent major sites of continental growth through tonalite-trondhjemite-granodiorite type (TTG-type) juvenile granitoid magmatism and accretion of oceanic crust and intra-oceanic arcs. The Asian continent includes several P-type orogenic belts, of which the largest are the Central Asian and Western Pacific. The Central Asian Orogenic Belt is dominated by P-type fossil orogens arranged with a regular northward subduction polarity. The Western Pacific is characterized by ongoing P-type orogeny related to the westward subduction of the Pacific plate. Asia has a multi-cratonic structure and its post-Palaeozoic history has witnessed amalgamation of the Laurasia composite continent and Pangaea supercontinent. Nowadays, Asia is surrounded by double-sided subduction zones, which generate new TTG-type crust and supply oceanic crust and microcontinents to its active margins. The TTG-crust can be tectonically eroded and subducted down to the mantle transition zone to form a ‘second’ continent, which may generate mantle upwelling, plumes, and extensive intra-plate volcanism. Moreover, recent plate movements around Asia are dominated by northward directions, which resulted in the India–Eurasia and Arabia–Eurasia collisions beginning at 50–45 and 23–20 Ma, respectively, and will result in Africa–Eurasia collision in the near future. Therefore, Asia is the best candidate to serve as the nucleus for a future supercontinent ‘Amasia’, likely to form 200–250 Ma in the future. In this paper we unravel a puzzle of continental growth in Asia through P-type orogeny by discussing its tectonic history and geological structure, subduction polarity in P-type orogens, tectonic erosion of TTG-type crust and arc subduction at convergent margins, generation of mantle plumes, and prospects of Asia growth and overgrowth.     

Comparison of Supercontinent Cycles in the Metallogeny of Rare Earth Elements

The distribution of integrated resources of large and superlarge deposits (LSLDs) of rare earth elements (REEs) is compared to the current model of supercontinent cyclicity during Earth’s evolution. It is found that REE LSLDs are related predominantly to igneous complexes (carbonatite, nepheline syenites, syenite-alkaline granites, subalkaline granites), which are often additionally enriched in the hypergenic zone. A certain part of the resources is concentrated in independent hypergenic formations represented by placers and ion-adsorbed clays. Each supercontinent cycle—Kenoran, Columbian, Rodinian, Pangean, and Amasian—is expressed in the REE metallogeny in particular way: we revealed significant intercycle variations in the amount of REE LSLDs, the variety of their types, total accumulated resources, and some other characteristics.     

地球和月球起源的非传统模型(英文)

46亿年以来 ,地球的内力活动是由地球液体内核上升的富氢挥发物流所维持的。为了解释这些导致地球内核如此巨量氢集中的作用 ,文中提出了一个关于地球、其它行星及作为一个整体的太阳系 ,其起源与演化的非传统的岩石学模型。排氢脉冲导致洋壳扩张的增强 ,而此则与创造出造山带的地壳变动幕相关。随后大洋底板活动的减弱 ,则招致褶皱陆壳的剥蚀 ,并伴有广泛展布的玄武岩岩浆作用 ,以及大洋周边优地槽区的稳定化。地壳发展旋回的有规则重复 ,都与地球历史中岩浆作用、变质作用、成矿作用和全球灾变的特殊特点相关。在最大的地核排氢期间 ,氢流体达到了平流层 ,并在这里形成有高反射力的水冰云。它们增加了地球的反射率 ,并成为地球全球冰封的基础。平流层冰云促进了对臭氧辐射盾牌的破坏 ,从而导致继冰期之后的生物灾难。     

Structure and evolution of the continental crust in the Baikal Fold Region

A summary of original Nd isotopic data on granitoids, silicic volcanics, and metasediments of the Baikal Fold Region is presented. The available Nd isotopic data, in combination with new geological and geochronological evidence, allowed recognition of the Early Baikalian (1000 ± 100 to 720 ± 20 Ma) and Late Baikalian (700 ± 10 to 590 ± 5 Ma) tectonic cycles in the geological evolution. The tectonic stacking, deformation, metamorphism, and granite formation are related to orogenic events that occurred 0.80–0.78 Ga and 0.61–0.59 Ga ago. The crust-forming events dated at 1.0–0.8 Ga and 0.70–0.62 Ga pertain to each cycle. The Early Baikalian crust formation developed largely in the relatively narrow and spatially separated Kichera and Param-Shamansky zones of troughs in the Baikal-Muya Belt. The formation and reworking of the Late Baikalian continental crust played the leading role in the Karalon-Mamakan, Yana, and Kater-Uakit zones and in the Svetlinsky Subzone of the Anamakit-Muya Zone in the Baikal-Muya Belt. In general, three large historical periods are recognized in the evolution of the Baikal Fold Region. The Early Baikalian period was characterized by prevalence of reworking of the older continental crust. The Late Baikalian-Early Caledonian period is distinguished by more extensive formation and transformation of the juvenile crust. The third, Late Paleozoic period was marked by reworking of the continental crust with juxtaposition of all older crustal protoliths. Two models of paleogeodynamic evolution of the Baikalian fold complexes are considered: (1) the autochthonous model that corresponds to the formation of suboceanic crust in rift-related basins of the Red Sea type and its subsequent reworking in the course of collision-related squeezing of paleorifts and intertrough basins and (2) the allochthonous model that implies the formation of fragments of the Baikal-Muya Belt at the shelf of the Rodinia supercontinent, their subsequent participation in the evolution of the Paleoasian ocean, and their eventual juxtaposition during Late Baikalian and Early Caledonian events in the structure of the Caledonian Siberian Superterrane of the Central Asian Foldbelt.     

The supercontinent cycle: A retrospective essay

The recognition that Earth history has been punctuated by supercontinents, the assembly and breakup of which have profoundly influenced the evolution of the geosphere, hydrosphere, atmosphere and biosphere, is arguably the most important development in Earth Science since the advent of plate tectonics. But whereas the widespread recognition of the importance of supercontinents is quite recent, the concept of a supercontinent cycle is not new and advocacy of episodicity in tectonic processes predates plate tectonics. In order to give current deliberations on the supercontinent cycle some historical perspective, we trace the development of ideas concerning long-term episodicity in tectonic processes from early views on episodic orogeny and continental crust formation, such as those embodied in the chelogenic cycle, through the first realization that such episodicity was the manifestation of the cyclic assembly and breakup of supercontinents, to the surge in interest in supercontinent reconstructions. We then chronicle some of the key contributions that led to the cycle's widespread recognition and the rapidly expanding developments of the past ten years.     

Multi-mechanism Orogenic Model of the Su-Jiao Orogenic Belt

The Su-Jiao orogenic belt is the eastern part of the Central Mountain System of China. Recent studies on its erogenic system indicate that the Su-Jiao erogenic belt is a complex orogenic belt which suffered at least 3 orogenies of different mechanisms in the Mesoproterozoic, Neoproterozoic and Triassic respectively. The Meso-Neoproterozoic orogenies belong to the Wilson cycle on the plate margins. The belt is a part of the Late Mesoproterozoic supercontinent Rodinia. The Triassic orogeny belongs to the re-orogeny of the non-Wilson cycle. Delamina-tion of mountain roots occurred after both the Wilson and non-Wilson cycles in the Su-Jiao erogenic belt. The large-amplitude isostatic uplift of mountains, magmatic activities and basin-forming and mountain-making in the upper crust, all indicate the general significance of delamination in the development of erogenic belts.     

Mantle convection modeling of the supercontinent cycle： Introversion,extroversion, or a combination？

The periodic assembly and dispersal of continental fragments,referred to as the supercontinent cycle,bear close relation to the evolution of mantle convection and plate tectonics.Supercontinent formation involves complex processes of"introversion"(closure of interior oceans),"extroversion"(closure of exterior oceans),or a combination of these processes in uniting dispersed continental fragments.Recent developments in numerical modeling and advancements in computation techniques enable us to simulate Earth’s mantle convection with drifting continents under realistic convection vigor and rheology in Earth-like geometry(i.e.,3D spherical-shell).We report a numerical simulation of 3D mantle convection,incorporating drifting deformable continents,to evaluate supercontinent processes in a realistic mantle convection regime.Our results show that supercontinents are assembled by a combination of introversion and extroversion processes.Small-scale thermal heterogeneity dominates deep mantle convection during the supercontinent cycle,although large-scale upwelling plumes intermittently originate under the drifting continents and/or the supercontinent.     

Continental growth and reworking on the edge of the Columbia and Rodinia supercontinents; 1.86–0.9 Ga accretionary orogeny in southwest Fennoscandia

Geological history from the late Palaeoproterozoic to early Neoproterozoic is dominated by the formation of the supercontinent Columbia, and its break-up and re-amalgamation into the next supercontinent, Rodinia. On a global scale, major orogenic events have been tied to the formation of either of these supercontinents, and records of extension are commonly linked to break-up events. Presented here is a synopsis of the geological evolution of southwest Fennoscandia during the ca. 1.9–0.9 Ga period. This region records a protracted history of continental growth and reworking in a long-lived accretionary orogen. Three major periods of continental growth are defined by the Transscandinavian Igneous Belt (1.86–1.66 Ga), Gothian (1.66–1.52 Ga), and Telemarkian (1.52–1.48 Ga) domains. The 1.47–1.38 Ga Hallandian–Danopolonian period featured reorganization of the subduction zone and over-riding plates, with limited evidence for continental collision. During the subsequent 1.38–1.15 Ga interval, the region is interpreted as being located inboard of a convergent margin that is not preserved today and hosted magmatism and sedimentation related to inboard extensional events. The 1.15–0.9 Ga period is host to Sveconorwegian orogenesis that marks the end of this long-lived accretionary orogen and features significant crustal deformation, metamorphism, and magmatism. Collision of an indenter, typically Amazonia, is commonly inferred for the cause of widespread Sveconorwegian orogenesis, but this remains inconclusive. An alternative is that orogenesis merely represents subduction, terrane accretion, crustal thickening, and burial and exhumation of continental crust, along an accretionary margin. During the Mesoproterozoic, southwest Fennoscandia was part of a much larger accretionary orogen that grew on the edge of the Columbia supercontinent and included Laurentia and Amazonia amongst other cratons. The chain of convergent margins along the western Pacific is the best analogue for this setting of Proterozoic crustal growth and tectonism.     

Continental crustal growth and the supercontinental cycle: evidence from the Central Asian Orogenic Belt

Studies of supercontinental cycle are mainly concentrated on the assembly, breakup and dispersal of supercontinents, and studies of continental crustal growth largely on the growth and loss (recycling) of the crust. These two problems have long been studied separately from each other. The Paleozoic–Mesozoic granites in the Central Asian Orogenic Belt have commonly positive Nd values, implying large-scale continental crustal growth in the Phanerozoic. They coincided temporally and spatially with the Phanerozoic Pangea supercontinental cycle, and overlapped in space with the P-wave high-V anomalies and calculated positions of subducted slabs for the last 180 Ma, all this suggests that the Phanerozoic Laurasia supercontinental assembly was accompanied by large-scale continental crustal growth in central Asia. Based on these observations, this paper proposes that there may be close and original correlations between a supercontinental cycle, continental crustal growth and catastrophic slab avalanches in the mantle. In this model we suggest that rapid continental crustal growth occurred during supercontinent assembly, whereas during supercontinental breakup and dispersal new additions of the crust were balanced by losses, resulting in a steady state system. Supercontinental cycle and continental crustal growth are both governed by changing patterns of mantle convection.     

大别山造山带中生代构造演化特征

大别山陆内造山带形成于早侏罗世晚期至早白恶世（J^31-K1），并具有分期演化特征。在构造演化序列上，可分出造山前期（J^21-J2）和造山主期（J3-K1）2个阶段。构造变形方面，基本构造格局为一大型逆冲推覆系统组成的构造楔形体，呈后展式扩展，造成的地壳短缩量可达46.8%，动力变质作用以高压动力变质为特征，发育高压动力变质岩（榴辉岩、蓝片岩和高压麻粒岩），形成于构造应力集中的主干逆掩断层上盘。岩浆岩属钙碱性岩石系列，中酸性岩石组合，其中岩石类型，稀土元素配分型式等所反映的构造运动强度均具有一定的特点。在陆内造山带形成过程中伴生了3期同造山磨拉石，朱集期磨拉石（J2z），段集期磨拉石（J3d）和下符桥期磨拉石（K2x），它们反映了不同造山时期构造运动强度的差异。     

The Precambrian supercontinent Palaeopangaea: two billion years of quasi-integrity and an appraisal of geological evidence

The Protopangaea-Palaeopangaea model for the Precambrian continental crust predicts quasi-integrity reflecting a dominant Lid Tectonics defined by a palaeomagnetic record showing prolonged near-static polar behaviour during very long time intervals (~2.7–2.2, 1.5–1.2, and 0.75–0.6 Ga). Intervening times show polar loops radiating from the geometric centre of the crust explaining the anomalous Precambrian magnetic inclination bias. The crustal lid was a symmetrical crescent-shaped body confined to a single hemisphere on the globe comparable in form to the Phanerozoic supercontinent (Neo)Pangaea. There were two major transitions in the tectonic regime when prolonged near-static motion was succeeded by widespread tectonic-magmatic activity, and each coincided with the major isotopic/geochemical signatures in the Precambrian record. The first comprised a ~90° reconfiguration of crust and mantle at ~2.2 Ga terminating the long 2.7–2.2 Ga static interval; the second was the largest continental break-up event in geological history and is constrained to the Ediacaran Period at ~0.6 Ga by multiple isotopic and geochemical signatures and the subsidence history of marine passive margins. Break-up of the lid at ~0.6 Ga defines a transition from dominant Lid Tectonics to dominant Plate Tectonics and is the primary cause of contrasts between the Precambrian and Phanerozoic aeons of geological times. The long interval of minimal continental motion in the mid-Proterozoic correlates with extensive emplacement of anorogenic anorthosite-rapakivi plutons unique to these times, and high-level emplacement was probably caused by blanketing of the mantle and comprehensive thermal weakening of the crust. Continental velocities were low during the two Proterozoic intervals characterized by profound glaciation (~2.4–2.2 and ~0.75–0.6 Ga) when partial or complete magmatic shutdown is likely to have reduced volcanic greenhouse gas production. Specific implications of Protopangaea-Palaeopangaea include: (i) support for recent evidence that 60–70% of the present continental crust had accreted by ~2.5 Ga; (ii) recognition from spatially constrained mineral provinces that sub-crustal lithosphere was already chemically differentiated by mid-Archaean times; (iii) strong axial alignment of younger greenstone belts, major Palaeoproterozoic shear zones, and later Meso–Neoproterozoic mobile/orogenic belts; (iv) concentration of anorogenic magmatism and progressive contraction of activity towards the orogenic margin subsequently to become the focus of Grenville (~1.1 Ga) orogenesis; and (v) late Neoproterozoic arc magmatism/tectonics at the instep margin of the continental crescent persisting until the Ediacaran continental break-up.