Plate Tectonic Evolution Research Articles

Speculations on the Mesozoic Plate tectonic evolution of eastern China

Several orogenic belts transecting eastern China are the sites of former convergent plate margins, although there have been varying views on the collisional framework of individual continental blocks, styles of convergence at these zones, and the timing of respective collisions. A tectonic study of eastern China, Mongolia and the southern Soviet Far East indicates the collision of the South China Block with a combined North China‐Northeast China Fold Zone Block in the Late Triassic‐Early Jurassic, their collective suturing to Eurasia in the Late Jurassic‐Early Cretaceous, followed by the Sikhote Alin‐Japan Block in the Mid to Late Cretaceous. The evidence is as follows: (1) A linear belt of Late Triassic‐Early Cretaceous granites and granodiorites trends east from the Qinlingshan through the Dabieshan to the Huaiyang massif. Ophiolites, flysch, subduction zone mélange, a paired metamorphic belt indicating north dipping subduction and marine strata of Carboniferous to Late Triassic age from the Qinlingshan define the suture between the North and South China Blocks, (2) A sinuous belt of ultramafics, blueschists, silicic to intermediate magmatism and west and north vergent folds and thrusts trend from the west margin of the Ordos Basin through central Inner Mongolia and along the east Great Khingan Range to the Amur River. Coupled with a Mid Jurassic‐Early Creataceous unconformity a suturing of eastern Chinese blocks to Eurasia along this zone is suggested, (3) A fold and thrust belt with ultramafics, flysch, blueschists and subduction zone mélange along the Ussuri River in northeast China indicates the suturing of the Sikhote Alin‐Japan Block to Eurasia along a west dipping subduction zone in the Mid to Late Cretaceous. Similarly, a tectonic study of southern China and Southeast Asia has revealed a complex regional mosaic of suture‐bounded terrains which nucleated about the eastern, western and southern margins of the Yangtze Craton during the Late Triassic and Early Jurassic. The evidence is as follows: (4) A north–south trending belt of ophiolites, blueschists, calc‐alkaline volcanics and subduction zone mélange, including granites, granodiorites and strongly deformed marine strata all of Late Triassic age exposed in the Longmenshan of Sichuan merge with the Kekexilishan ophiolite zone into the Ailaoshan‐Tengtiaohe ophiolite and blueschist belt in central Yunnan along which the Songban‐Ganzi Complex and the Shan‐Thai‐Malaya Block join the Craton, and (5) A southeastern prolongation of the Ailaoshan‐Tengtiaohe belt bifurcates into the southeast trending Konvoi zone of northern Vietnam and the north‐south trending Pak Lay‐Luang Prabang zone of Laos and eastern Thailand. Zones of ophiolite, calc‐alkaline volcanics and strong Late Triassic deformation, they separate the Indosinia and Shan‐Thai‐Malaya Blocks from the Craton respectively. These findings differ significantly from previous interpretations of a Late Paleozoic consolidation of South‐Eastern Asia as well as disputing the existence of a true Pangea.

Speculations on the Mesozoic plate tectonic evolution of eastern China

Speculations on the Mesozoic plate tectonic evolution of eastern China

The Canada Basin: Aeromagnetic constraints on structure and evolution

Aeromagnetic data over the Canada Basin and Alpha Ridge-Ellesmere Island junction are re-examined together with available bathymetry, free-air gravity and magnetic source depths calculated from the aeromagnetics. The plate tectonic evolution of this area remains largely conjectural; for example, the data from the basin and the adjacent continental margins have not settled the Alaska rotation controversy. Did the Canada Basin open by a rotation of the Alaska and Chukchi blocks away from the Canadian Arctic margin, or did the southern Canada Basin open by motion of the Chukchi block parallel to the Alaska North Slope? What we do conclude is: 1. (1) The southern Canada Basin consists of oceanic crust produced by spreading from a now-extinct axis marked by a gravity high and magnetic low. The opening took place largely or entirely during the time of the M-Series (155-115 m.y. B.P.) although the lineations are too few and too irregular to allow certain correlation to the reversal time scale. 2. (2) The central Canada Basin, north of Prince Patrick Island, probably opened by spreading normal to the margin. The segmented character of the magnetics and perhaps topography, suggests small transform faults (ca. 100 km spacing) extending at least several hundred kilometers into the basin. If these trends are real, major subsequent motion parallel to the Canadian Arctic margin can be ruled out. 3. (3) We speculate that the southern Canada Basin extinct axis extended to a triple junction near 79°N, 140°W, with one rift trending toward Ellesmere Is and the other into the Mendeleev Abyssal Plain. 4. (4) The transition between the low magnetic amplitudes of the southern Canada Basin to the high amplitudes of the northern Canada Basin-Alpha Mendeleev Ridge province is gradual and linear anomalies extend through the transition. 5. (5) The area north of Ellesmere Island can be divided into five discrete magnetic anomaly provinces, some of them sharply demarcated by major lineaments (faults?) which may provide plate kinematic constraints. The Alpha Ridge basement is depressed by 3–4 km along a 100 km wide magnetic basement trough along the Alpha Ridge-Ellesmere Is. margin.

Propagating rift explanation for the tectonic evolution of the northeast Pacific—the pseudomovie

We have developed a new computer graphic technique to use in reconstructing plate tectonic evolution and to make movies illustrating this evolution. Using this technique, we have deciphered the evolutionary history of the Juan de Fuca area in the northeast Pacific, and show that a combination of seafloor spreading and rift propagation can explain this seemingly complex area as a simple consequence of the interaction of two rigid plates.

Tectonic Evolution of the Terrestrial Planets

The style and evolution of tectonics on the terrestrial planets differ substantially. The style is related to the thickness of the lithosphere and to whether the lithosphere is divided into distinct, mobile plates that can be recycled into the mantle, as on Earth, or is a single spherical shell, as on the moon, Mars, and Mercury. The evolution of a planetary lithosphere and the development of plate tectonics appear to be influenced by several factors, including planetary size, chemistry, and external and internal heat sources. Vertical tectonic movement due to lithospheric loading or uplift is similar on all of the terrestrial planets and is controlled by the local thickness and rheology of the lithosphere. The surface of Venus, although known only at low resolution, displays features both similar to those on Earth (mountain belts, high plateaus) and similar to those on the smaller planets (possible impact basins). Improved understanding of the tectonic evolution of Venus will permit an evaluation of the relative roles of planetary size and chemistry in determining evolutionary style.

Plate motions in the Alpine region and their correlation to the opening of the Atlantic ocean

The plate tectonic evolution of the Alps is intimately related to the stepwise protrusion of the Atlantic ocean to the north. The South Penninic oceanic basin of the Alps is part of the spreading system of the early Atlantic ocean in the Jurassic. In the Lower Cretacous, the North Peeninic basin forms as an appendix of the Atlantic in its second stage of evolution, connected with it via the Pyrenees trough and the Bay of Biscay. Subduction in the South Penninic ocean by convergent motion of the Brianconian and the Adriatic plates leads to a first continental collision in about mid-Cretaceous time. In the Upper Cretaceous, when the Atlantic ocean protrudes between North America and Greenland, Eurasia and Africa move divergently, and there is relative quiescence in the Alps. In the Tertiary, the Atlantic ocean spreads between Greenland and Scandinavia which results in convergent motion between Eurasia and Africa and important compressional events in the Alps.

Plate Tectonic Evolution of Southern South America-Scotia Sea-Antarctica Area: ABSTRACT

Jurassic, Cretaceous, and Tertiary stratigraphy is analyzed End_Page 929------------------------------ in relation to its plate tectonic significance. Based on the I. O. Norton-J. G. Sclater reconstructions for the breakup of southern Gondwana, a scheme is developed illustrating the plate tectonic evolution from Triassic to present that includes (1) opening of the south Atlantic-Indian Ocean areas, (2) the formation of a marginal basin in the southern Andes in Late Jurassic-Early Cretaceous and its subsequent destruction by arc-continent collision and attendant ophiolite obduction, and (3) interaction during the Tertiary of the convergent Pacific margin and a northward migrating RRR triple junction. End_of_Article - Last_Page 930------------

Geochemical soil prospecting in Northwest Kalimantan, Indonesia

A target area in northwestern Kalimantan, Indonesia, already defined by a geochemical stream-sediment survey, has been further investigated by geochemical analysis of soils and samples of test pits. Overlapping geochemical anomalies in the soils were found for Cu, Mo, Au and Bi. Anomalies and high values of the other elements, Pb, Zn, Fe, Mn and As, can be explained by lithology and by scavenging and coprecipitation phenomena at the break of slopes. With the aid of detailed geochemical mapping and mineralogical and petrographic analysis the Cu-Mo-Au-Bi anomaly was explained by a porphyry-type mineralization consisting mainly of chalcopyrite and molybdenite within a quartz-enriched granodiorite. Hydrothermal alteration consists of a potassic zone, including the anomaly, and a broad propylitic zone. This type of mineralization is related to the plate-tectonic evolution of Sundaland. The possibility of a belt of porphyry-type mineralization in western Kalimantan is proposed.

Evidence from Canada and Alaska on plate tectonic evolution of the Arctic Ocean Basin

A new model for the plate tectonic evolution of the Amerasian sector of the Arctic Ocean is suggested here using data from petroleum exploration on its margin. More than 500 km of late Cretaceous dextral slip is indicated for the SW–NE trending Kaltag fault system in Alaska and northwestern Canada. Terminating against the Kaltag, an older fault system trends along the Canadian Cordillera, with dextral slip of thousands of kilometres. Its offset by the Kaltag is postulated to follow the southern margin of the Canada Basin. Restoration of the offset creates a great circle lineament from the Asian end of the Lomonosov Ridge through western North America along which Jurassic–Cretaceous transform movement could have accommodated spreading about the Alpha Ridge. Accretion of the newly-formed lithosphere to a Palaeozoic Canada Basin created the Amerasian Basin in essentially its present configuration, modified by subsequent Kaltag movement.

Cenozoic continental separation between Europe and Greenland

Prior to the Cenozoic a shallow sea extending into the North Sea and the Barents Sea existed between Greenland and Europe. Sea-floor spreading along an axis within this epicontinental basin commenced in the Late Paleocene. However, the geologic development of the region is characterized by two major plate tectonic phases. During the first phase oceanic crust was created by sea-floor spreading south of the Greenland—Senja Fracture Zone, whereas the relative motion between northeast Greenland and Svalbard took place along a regional transform fault zone without formation of a deep basin. The second phase started in the Middle Oligocene when the relative plate motion became west-northwest with subsequent formation of the Greenland Sea by sea-floor spreading. Plate tectonic analysis also shows that generation of the Icelandic type ocean crust has been maintained throughout the entire Cenozoic as reflected by the shallow Faeroe—Iceland Ridge. The plate tectonic evolution has caused important constraints on the paleo-oceanography of the Norwegian—Greenland Sea and adjacent areas. In particular, two land bridges may at times have allowed migration of continental faunas and floras, thus by passing the growing North Atlantic Ocean. The land bridges have also acted as important barriers to the surface and deep water exchange between the Norwegian—Greenland Sea, the Arctic Ocean and the main basins of the North Atlantic Ocean. In the south, the main platform of the aseismic Faeroe—Iceland Ridge subsided below sea level in the Miocene. In the north, deep water did not flow between the margins off northeast Greenland and Svalbard before the Middle Oligocene.

Geodynamic Peaks in Alpinotype Orogenies and Changes in Ocean-Floor Spreading During Late Jurassic-Late Tertiary Time

Modern data indicate that peaks of tectonic displacement alternate with relative tectonic quiescence and that dates of changes in plate motion coincide with times of orogeny. These relations seem to be substantiated by contemporaneity of major discontinuities in seafloor spreading and widespread angular unconformities related to mountain building. Examples are the spreading discontinuities 112, 77, 40, and 10 m.y. ago which are coeval with intense orogenic phases. They are turning points in geotectonic development of the earth--major orogenies occur contemporaneously with first-order readjustments in the plate-tectonic pattern and are reflected in sea-level changes. Thus a close kinematic relation of the processes is suggested. Evidently, orogenic paroxysms are geneticall associated with episodic reorganizations in direction and rate of plate motion. Alpinotype mountain building occurred along mobile continental margins of plates as soon as these were affected by intense compressive orogenic stress caused by a change to convergent interplate motions. Thus, phases of geodynamic activity become apparent in the history of lithospheric plate motions. The specific timing of these phases is an essential geologic parameter and base for further reproduction of plate-tectonic evolution in time and space.

Tectonic progradation and plate tectonic evolution of the Alps

Rifting and spreading, trench formation, flysch deposition, subduction and nappe formation prograde from internal to external parts of the Alpine orogen. The progradation is a characteristic feature of the evolution of the Alps. A plate tectonics model based on this cognition is presented and an attempt is made to integrate the plate movements of the Alpine region during the Mesozoic and Cenozoic into the plate pattern of the Western Mediterranean. Important events in the evolution of the Alps are the successive opening and closing of the Piedmont (South Penninic) and Valais (North Penninic) oceans, and the two continental collisions related to this. The southward drift of the Briançonian plate in the Cretaceous closes the Piedmont and opens the Valais ocean. The evolution of these oceans is related to the plate movements in the North Atlantic. The second continental collision is followed by the formation of an exogeosyncline, the molasse foredeep. Prograding orogens like the Alps are most likely to evolve in an originally continental environment by rifting. Retrograding orogens, however, indicate an originally oceanic environment with well-developed magmatic arcs and back-arc basins.

The western and northern margin off svalbard

Recent geophysical measurements, including multi-channel seismic reflection, on the Svalbard passive margin have revealed that it has undergone a complex geological history which largely reflects the plate tectonic evolution of the Greenland Sea and the Arctic Ocean. The western margin (75–80°N) is of a sheared-rifted type, along which the rifted margin developed subsequent to a change in the pole of plate rotation about 36 m.y. B.P. The north-trending Hornsund Fault on the central shelf and the eastern escarpment of the Knipovich Ridge naturally divide the margin into three structural units. These main marginal structures strike north, paralleling the regional onshore fault trends. This trend also parallels the direction of Early Tertiary plate motion between Svalbard and Greenland. Thus, the western Svalbard margin was initially a zone of shear, and the shear movements have affected the adjacent continental crust. Although, the nature and location of the continent—ocean crustal transition is somewhat uncertain, it is unlikely to lie east of the Hornsund Fault. The northern margin, including the Yermak marginal plateau, is terminated to the west by the Spitsbergen Fracture Zone system. This margin is of a rifted type and the preliminary analysis indicates that the main part of the investigated area is underlain by continental crust.

Earthquake source mechanisms and plate tectonics

This review and the accompanying references will be concerned mainly with earthquake source studies pertinent to plate tectonics. Studies on geological problems, lithospheric flexure and mantle convection are discussed in other reviews in this volume.In the earlier stage of the development of plate tectonics, the distribution of earthquakes and the geometrical configuration of earthquake source mechanisms played an important role. As more sophisticated techniques for retrieving earthquake source parameters (synthetic seismogram method for both body and surface waves, inversion method, matching filter method, etc.) were developed, emphasis in the last four years was placed on the determination of not only the geometry of the source but also more quantitative parameters such as the stress drop, the amount of slip, the complexity, the strength of non‐isotropic components, and the spectral characteristics. Also significant emphasis was placed on intraplate earthquakes and events on continental plate boundaries.

Stability of quadruple junctions

THE analysis of triple junctions (points on the Earth where three lithospheric plates meet) has proved to be a powerful tool in deciphering the plate tectonic evolution of the Earth. In their classic paper on the evolution of triple junctions1, McKenzie and Morgan dismissed the possibility of stable quadruple junctions existing more than instantaneously. We show here that quadruple junctions can be stable according to the vector velocity stability criteria of McKenzie and Morgan.

Plate-Tectonic Evolution and Delayed Partial Melting in Western Papua New Guinea

Late Cainozoic volcanoes in the Papua New Guinea Highlands overlie cratonic crust but yet produce arc-type volcanics. The data from the study of these supposedly anomalous igneous rocks suggest that a mantle magma source which has been chemically modified during subduction and which has passed through rapid and pronounced changes in tectonic setting may later on be the source of magmas produced during a favourable but non-arc tectonic regime.

The Non-Kuhnian Nature of the Recent Revolution in the Earth Sciences

It is without doubt that the earth sciences were rocked to the core by a revolution in the late sixties with the initial acceptance of Harry Hess’s hypothesis of seafloor spreading and subsequent development and acceptance of plate tectonics. The major aim of this essay is to show precisely why this revolution is not Kuhnian. However, my reasons for claiming that Kuhn’s model fails to apply are at variance with Ruse [27] but in much agreement with R. Laudan [18]. I shall highlight our differences as space permits.There are two general accounts of the rise of continental drift and plate tectonics which satisfy Kuhn’s model of scientific growth and change. (1) The geosciences prior to the acceptance of seafloor spreading and plate tectonics were in a pre-paradigm state. Earth scientists solved no problems within geological domains, but only argued among themselves about which of the various schools of thought provided the best framework for attacking geological problems.

Neogene Basin Formation in Relation to Plate-Tectonic Evolution of San Andreas Fault System, California

More than 90% of the known petroleum accumulations west of the San Andreas fault in California are in strata deposited in areally restricted Neogene basins that formed during a major tectonic reorganization of western California. These deep, localized Neogene basins replaced broad, regionally persistent Paleogene depositional aprons, although some of the Neogene basins in northern and central California had Paleogene precursors. The evolution of each of the Neogene basins is complex, and aspects of the kinematics of each are unique; nonetheless, all can be considered products of an overall right-lateral shear system associated with a sliding margin between the Pacific and North American lithospheric plates. The sliding margin developed in western California about 29 m.y. ago, when the Pacific plate contacted North America after subduction of the intervening Farallon plate. The initial position of the common boundary between the Pacific and North American plates was along the continental margin. Right slip between the Pacific and North American plates gradually shifted eastward to right-slip faults, such as the San Andreas, located farther inland. This shift seems to be documented by relations in the southern California area. About 300 km of right slip has occurred along the San Andreas fault during the past 10 to 15 m.y., and at least several hundred additional kilometers along associated right-slip faults of the San Andreas system. The Neogene basins in southern California began to develop during the interval in which the boundary between the Pacific and North American plates shifted from the continental edge to the San Andreas fault, apparently because the step-by-step switch to different surfaces of weakness caused local extension and compression within a broad zone of right-lateral shear. A major phase of basin formation appears to have been synchronous with a change in azimuth of relative shear between the Pacific and North American plates to a more westerly direction, resulting in extensional strain. This change in motion initiated basin development in offshore central and northern California and affected the ongoing development of basins as a result of right slip along the San Andreas and related faults in other parts of California.

James B. Macelwane Award to Dan McKenzie, Gerald Schubert and Vytenis M. Vasyliunas

To those earth scientists who have followed the revolutionary development of plate tectonics from its dawning, it may come as a surprise that Dan McKenzie can have done so much and still be young enough to qualify for the James B. Macelwane Award. Nonetheless it is so. He was born on February 21, 1941. He received his advanced education at King's College, Cambridge University, and was awarded a B.A. in 1963 and a Ph.D. in 1966. He became a Fellow of the college in 1965. He was fortunate enough to be a student in Edward Bullard's Department of Geodesy and Geophysics just in those exciting years when the validity of sea floor spreading was demonstrated. McKenzie was one of the first to realize the broader implications of the computer fitting of continents by Bullard and others which assumed that the drifting crust is rigid.

Part 5. Plate boundary evolution in the New Guinea region: Volcanic and plate tectonic evolution of central Papua New Guinea

Volcanic activity in central Papua New Guinea began in the Upper Triassic with submarine and terrestrial eruption of andesitic and dacitic lavas on and adjacent to the north-east corner of the Palaeozoic Australian continental crust. Minor basaltic to rhyolitic eruptions took place during the Jurassic in the same general area. During the Cretaceous, volcanic activity increased in intensity and distribution, spreading to the north and west (Fig.1), and produced mainly andesitic lavas, both subaerial and submarine. The increase in activity in the Cretaceous, may correlate with the beginning of spreading in the Pacific basin to the northeast (Packham, 1973), and could therefore have been a result of the first subduction in the area. There is no evidence to link the earlier volcanism with subduction, although it took place on or near a plate boundary.