Global continental and ocean basin reconstructions since 200Ma

Abstract

The role of rifting in the formation of the recent structure of the Mongolia-Okhotsk orogen is extremely high, but it is still underestimated with regard to flanks of the Dzhagda segment of this orogen. Current researches refer to a combination of physical and chemical processes in the depth of the lithosphere, as well as interactions between the Izanagi, Eurasian and Pacific plates as explanations of repeated rifting events in East Asia. Upwelling of the asthenosphere due to significant differences in the lithosphere thickness (150-200 km under cratons, and only 100 km under orogenic belts) was viewed as a cause of rifting. It was assumed that rifting was controlled by mantle plumes, volcanism and heat regime. Structures bordering the Mongolia-Okhotsk orogen from north and south were considered as superimposed or marginal troughs. Recent studies have revealed numerous riftogenic Late Mesozoic structures in the Central Asian orogenic belt, which resulted from the collision of the Siberian and North Chinese cratons. New geological survey and geochemical data on volcanites confirmed the riftogenic origin of the Zeya-Uda (or Uda) and Nora-Selemdzha troughs bordering the Mongolia-Okhotsk orogen from north and south, respectively ( Fig. 1, and 2). Geology and geophysics of those troughs has been described. It is noted that riftogenic volcanites formed later in the east than those in the west. The Late Mesozoic rifting is widely manifested in North Eastern Asia across the area exceeding two million square kilometers, from Lake Baikal to the Sikhote-Alin region (west to east) and from the Southern Yakutia basins to North China (north to south). It is evidenced by intra-continental rifts of various trends, volcanic provinces and extension structures along large strike-slip faults [Ren et al., 2002]. The Uda and Nora-Selemdzha marginal troughs located along the Dzhagda segment of the Mongolia-Okhotsk orogen give evidence that compression was replaced by extension in the study area. Rifting structures may be due to physical and chemical processes, the development of plumes [Yarmolyuk et al., 2000], as well as the interaction between the Pacific and Eurasian lithospheric plates. Volcanic activity took place earlier in the west and then propagated to the east due to the shifting of the subduction zone in this direction. This paper analyzes regional and global geological events on the basis of new drilling data and the geochronological dating of volcanites. It describes the Late Mesozoic stage of rifting at the flanks of the Dzhagda segment of the Mongolia-Okhotsk collisional orogen. P a l e o g e o d y n a m i c s RESEARCH ARTICLEДля цитирования: Кириллова Г.Л. Позднемезозойский рифтогенез на флангах Джагдинского звена Монголо-Охотского коллизионного орогена: глобальные и региональные аспекты // Геодинамика и тектонофизика.

Slow Long‐Term Exhumation of the West Central Andean Plate Boundary, Chile

“…The field area of this study, outlined in red, sits at the northern end of Chile directly under the Arica bend within a zone of relatively consistent slab age, volcanic distribution, subduction angle, distance from trench, convergence orientation, and morphology. Location of trench/plate boundaries and oceanic crustal ages are derived from the GPLATES global plate model (Müller et al, 2008; Seton et al, 2012). Locations of aseismic ridges, labeled and outlined in gray, are derived from the GEBCO global bathymetry model (Weatherall et al, 2015).…”

Geology, Mantle Tomography, and Inclination Corrected Paleogeographic Trajectories Support Westward Subduction During Cretaceous Orogenesis in the North American Cordillera

“…With improvements in computing power and high-resolution seismic arrays, such as USArray (Williams et al 2010), these advances have now reached a level where they can be integrated with geological models based on surface geology (Sigloch 2011;Sigloch and Mihalynuk 2013). Moreover, the seismic tomography can be used in consort with recently developed kinematic models for plate motions in deep-mantle reference frames based on seafloor-spreading history, hotspot migration, paleomagnetism, and moving continents (Müller et al 1993;O'Neill et al 2005;Torsvik et al 2008a, b;Doubrovine et al 2012;Shephard et al 2012;Seton et al 2012) to constrain the tectonic development of orogenic belts. My goal here is to provide a brief, but modern treatment of the geology, then to show how existing plate trajectories -once modified to account for compaction errors -fit remarkably well with the geology, both spatially and temporally.…”

“…During the opening of the Atlantic Ocean, at least during the JurassicEarly Cretaceous periods, North America was moving westward from a more or less fixed Africa (Coney 1971;Torsvik et al 2008a;Steinberger and Torsvik 2008;Seton et al 2012). This implies that the slab wall formed during westward-dipping subduction because if the slab was easterly dipping beneath western North America -as generally assumed by most workers to have been the case since at least the Triassic -the trench would have migrated westward and, as long as the slab sank vertically, left an inclined slab at depth which dips toward older trench positions.…”

“…One can use Gplates (Boyden et al 2011;Gurnis et al 2012;Williams et al 2012) as did Sigloch and Mihalynuk (2013) to compare the location of the eastern vertical slab with the predicted paleogeographic trajectories for North America from 140 Ma to present as deduced from the five separate models of Shephard et al (2012): (1) a hybrid hotspot model, which uses moving hotspots in both the Atlantic and Indian oceans from 100 Ma to the present (O'Neill et al 2005), and fixed hotspots for older ages (Müller et al 1993); (2) a fixed hotspot reference frame model (Müller et al 1993); (3) framework that also assumes no longitudinal motion of Africa (Steinberger and Torsvik 2008;Seton et al 2012); and (5) an entirely different type of model that matches subducted slabs with subduction zones (van der Meer et al 2010). Uncertainty pervades nearly every aspect of the reconstructions, including possible errors in properly locating and dating hotspots, the shape of the North American margin, error envelopes in paleomagnetic pole locations and ages, errors in assigning movement to hotspots, and in the case of the subduction model, mistakes in matching mantle anomalies with subduction zones once the subducting slab has broken.…”

The Manihiki Plateau—a key to missing hotspot tracks?

“…Wessel et al 2006;Wessel & Kroenke 2008), which are used in plate reconstruction models (e.g. Chandler et al 2012;Seton et al 2012).…”