Explore the vast range of titles available.

Convergence between the Indian and Asian plates has reshaped large parts of Asia, changing regional climate and biodiversity, yet geodynamic models fundamentally diverge on how convergence was accommodated since the India–Asia collision. Here we report palaeomagnetic data from the Burma Terrane, which is at the eastern edge of the collision zone and is famous for its Cretaceous amber biota, to better determine the evolution of the India–Asia collision. The Burma Terrane was part of a Trans-Tethyan island arc and stood at a near-equatorial southern latitude at ~95 Ma, suggesting island endemism for the Burmese amber biota. The Burma Terrane underwent significant clockwise rotation between ~80 and 50 Ma, causing its subduction margin to become hyper-oblique. Subsequently, it was translated northward on the Indian Plate by an exceptional distance of at least 2,000 km along a dextral strike-slip fault system in the east. Our reconstructions are only compatible with geodynamic models involving an initial collision of India with a near-equatorial Trans-Tethyan subduction system at ~60 Ma, followed by a later collision with the Asian margin.

The formation of a global network of plate boundaries surrounding a mosaic of lithospheric fragments was a key step in the emergence of Earth’s plate tectonics. So far, propositions for plate boundary formation are regional in nature; how plate boundaries are created over thousands of kilometres in geologically short periods remains elusive. Here we show from geological observations that a >12,000-km-long plate boundary formed between the Indian and African plates around 105 Myr ago. This boundary comprised subduction segments from the eastern Mediterranean region to a newly established India–Africa rotation pole in the west Indian Ocean, where it transitioned into a ridge between India and Madagascar. We identify coeval mantle plume rise below Madagascar–India as the only viable trigger of this plate rotation. For this, we provide a proof of concept by torque balance modelling, which reveals that the Indian and African cratonic keels were important in determining plate rotation and subduction initiation in response to the spreading plume head. Our results show that plumes may provide a non-plate-tectonic mechanism for large-plate rotation, initiating divergent and convergent plate boundaries far away from the plume head. We suggest that this mechanism may be an underlying cause of the emergence of modern plate tectonics. A mantle plume induced plate rotation that initiated subduction and rifting along a >12,000 km plate boundary about 105 Myr ago, according to an analysis of geological data and numerical simulations.

The 11 March 2011 magnitude 9.0 Tohoku-Oki megathrust earthquake just off the Eastern coast of Japan was one of the largest earthquakes in recorded history. Japan's considerable investment in seismic and geodetic networks allowed for the collection of rapid and reliable data on the mechanics of the earthquake and the devastating tsunami that followed (see the Perspective by Heki ). Sato et al. (p. 1395 , published online 19 May) describe the huge displacements from ocean bottom transponders—previously placed directly above the earthquake's hypocenter—communicating with Global Positioning System (GPS) receivers aboard a ship. Simons et al. (p. 1421 , published online 19 May) used land-based GPS receivers and tsunami gauge measurements to model the kinematics and extent of the earthquake, comparing it to past earthquakes in Japan and elsewhere. Finally, Ide et al. (p. 1426 , published online 19 May) used finite-source imaging to model the evolution of the earthquake's rupture that revealed a strong depth dependence in both slip and seismic energy. These initial results provide fundamental insights into the behavior of rare, very large earthquakes that may aid in preparation and early warning efforts for future tsunamis following subduction zone earthquakes. Detailed geophysical measurements reveal features of the 2011 Tohoku-Oki megathrust earthquake. The moment magnitude ( M w ) = 9.0 2011 Tohoku-Oki mega-thrust earthquake occurred off the coast of northeastern Japan. Combining Global Positioning System (GPS) and acoustic data, we detected very large sea-floor movements associated with this event directly above the focal region. An area with more than 20 meters of horizontal displacement, that is, four times larger than those detected on land, stretches several tens of kilometers long along the trench; the largest amount reaches about 24 meters toward east-southeast just above the hypocenter. Furthermore, nearly 3 meters of vertical uplift occurred, contrary to observed terrestrial subsidence.

The ancient cores of continents (cratons) are underlain by mantle keels—volumes of melt-depleted, mechanically resistant, buoyant and diamondiferous mantle up to 350 kilometres thick, which have remained isolated from the hotter and denser convecting mantle for more than two billion years. Mantle keels formed only in the Early Earth (approximately 1.5 to 3.5 billion years ago in the Precambrian eon); they have no modern analogues 1 – 4 . Many keels show layering in terms of degree of melt depletion 5 – 7 . The origin of such layered lithosphere remains unknown and may be indicative of a global tectonics mode (plate rather than plume tectonics) operating in the Early Earth. Here we investigate the possible origin of mantle keels using models of oceanic subduction followed by arc-continent collision at increased mantle temperatures (150–250 degrees Celsius higher than the present-day values). We demonstrate that after Archaean plate tectonics began, the hot, ductile, positively buoyant, melt-depleted sublithospheric mantle layer located under subducting oceanic plates was unable to subduct together with the slab. The moving slab left behind craton-scale emplacements of viscous protokeel beneath adjacent continental domains. Estimates of the thickness of this sublithospheric depleted mantle show that this mechanism was efficient at the time of the major statistical maxima of cratonic lithosphere ages. Subsequent conductive cooling of these protokeels would produce mantle keels with their low modern temperatures, which are suitable for diamond formation. Precambrian subduction of oceanic plates with highly depleted mantle is thus a prerequisite for the formation of thick layered lithosphere under the continents, which permitted their longevity and survival in subsequent plate tectonic processes. Modelling reveals how thick diamondiferous continental mantle ‘keels’ were formed only at increased mantle temperatures when the melt-depleted, hot, ductile mantle located under subducting oceanic plates flowed backwards, underplating the continents.

The existence of a typical triple junction in Colombia is crucial for understanding plate convergence and coupling among the South American Plate, the subducting Nazca Plate, and the Caribbean Plate. However, locating this triple junction is challenging due to complex geodynamic evolution and uncertainty in the slab boundaries. Here, we developed a high‐resolution Lg‐wave attenuation model for Colombia and surrounding areas to constrain crustal magmatic activity, link deep processes with surface volcanism, and identify potential slab boundaries. The area encompassing Central America, western Colombia, and Ecuador exhibits strong Lg attenuation and a concentration of volcanoes, indicating thermal anomalies in the crust. In line with velocity structure, volcanism, seismicity, and isotopic dating, the thermal anomalies caused by the subducting Nazca and Caribbean slabs suggest the presence of three subducting slabs beneath the South American Plate, with a triple junction located at approximately 7.5°N, 77°W.

Realistic appraisal of paleoclimatic information obtained from a particular location requires accurate knowledge of its paleolatitude defined relative to the Earth's spin-axis. This is crucial to, among others, correctly assess the amount of solar energy received at a location at the moment of sediment deposition. The paleolatitude of an arbitrary location can in principle be reconstructed from tectonic plate reconstructions that (1) restore the relative motions between plates based on (marine) magnetic anomalies, and (2) reconstruct all plates relative to the spin axis using a paleomagnetic reference frame based on a global apparent polar wander path. Whereas many studies do employ high-quality relative plate reconstructions, the necessity of using a paleomagnetic reference frame for climate studies rather than a mantle reference frame appears under-appreciated. In this paper, we briefly summarize the theory of plate tectonic reconstructions and their reference frames tailored towards applications of paleoclimate reconstruction, and show that using a mantle reference frame, which defines plate positions relative to the mantle, instead of a paleomagnetic reference frame may introduce errors in paleolatitude of more than 15° (>1500 km). This is because mantle reference frames cannot constrain, or are specifically corrected for the effects of true polar wander. We used the latest, state-of-the-art plate reconstructions to build a global plate circuit, and developed an online, user-friendly paleolatitude calculator for the last 200 million years by placing this plate circuit in three widely used global apparent polar wander paths. As a novelty, this calculator adds error bars to paleolatitude estimates that can be incorporated in climate modeling. The calculator is available at www.paleolatitude.org. We illustrate the use of the paleolatitude calculator by showing how an apparent wide spread in Eocene sea surface temperatures of southern high latitudes may be in part explained by a much wider paleolatitudinal distribution of sites than previously assumed.

A tectonic Plate Motion Model (PMM) is essential for geodetic applications, while contributing to the understanding of geodynamic processes affecting the Earth's surface. We introduce a PMM derived from the horizontal velocities of 518 sites extracted from the ITRF2020 solution. These sites were chosen away from plate boundaries, Glacial Isostatic Adjustment regions, and other deforming zones. Unlike the ITRF2014‐PMM, which showed no significant Origin Rate Bias (ORB), velocities used to determine the ITRF2020‐PMM exhibit a statistically significant ORB (0.74 ± 0.09 mm/yr along the Z‐component). Users are advised to add the estimated ORB to the horizontal velocities predicted by the ITRF2020‐PMM rotation poles for full consistency with the ITRF2020. However, the predicted vertical velocities resulting from the addition of the ORB should be discarded. The overall precision with which the ITRF2020 velocity field is represented by the rigid ITRF2020‐PMM is at the level of 0.25 mm/yr WRMS. Plain Language Summary The Earth's surface is divided in large and small tectonic plates, which evolve and move slowly over time, resulting in lateral displacements of the ground surface typically of the order of a few cm/yr. Because of the relative motion between tectonic plates, plate boundaries can be either divergent (when two plates move away from each other), convergent (when two plates collide) or transform (when two plates slide past each other). Plate motion models are used to quantify the relative motions of the plates with respect to each other, and are determined using geological data or observations collected by space geodesy instruments distributed over different plates at the Earth's surface. In the latter case, space geodesy observations from the four space geodetic techniques covering more than 40 years of data are analyzed to estimate the long‐term displacements (or velocities) of each instrument in a well defined and self‐consistent global reference frame. The derived velocity field is then used to estimate a comprehensive plate motion model (PMM). This article presents a PMM for 13 tectonic plates based on a subset of the velocity field from the recently released International Terrestrial Reference Frame 2020 (ITRF2020); see https://itrf.ign.fr/en/solutions/ITRF2020. Key Points We derive a plate motion model for 13 tectonic plates from the ITRF2020 horizontal velocity field Built under the rigid‐plate motion hypothesis, the model represents the ITRF2020 velocity field with a precision of 0.25 mm/yr WRMS The residual velocities would show a global northward motion if a translation rate was not included in the inversion model

The discovery of slow earthquakes has revolutionized the field of earthquake seismology. Defining the locations of these events and the conditions that favor their occurrence provides important insights into the slip behavior of tectonic faults. We report on a family of recurring slow-slip events (SSEs) on the plate interface immediately seaward of repeated historical moment magnitude (M w) 8 earthquake rupture areas offshore of Japan. The SSEs continue for days to several weeks, include both spontaneous and triggered slip, recur every 8 to 15 months, and are accompanied by swarms of low-frequency tremors. We can explain the SSEs with 1 to 4 centimeters of slip along the megathrust, centered 25 to 35 kilometers (km) from the trench (4 to 10 km depth). The SSEs accommodate 30 to 55% of the plate motion, indicating frequent release of accumulated strain near the trench.

Establishing when modern-style plate tectonics with deep subduction began on Earth is one of the biggest questions in geosciences today. A lack of Archean age (>2.5 billion y ago [Ga]) eclogites or eclogite-facies crustal rocks (the high-pressure equivalent of basalt or gabbro) has led to an assertion that modern plate tectonics did not operate in the Archean. Here, we report eclogite-facies garnet clinopyroxenite associated with metagabbro in 2.52- to 2.53-billion-y-old ophiolitic mélange in the northern Central Orogenic Belt (COB) within the North China Craton. The garnet clinopyroxenites with normal mid-ocean ridge basalt (N-MORB) geochemical signatures are relicts of oceanic crust, recording peak eclogite-facies metamorphic assemblages indicating conditions of 792 to 890 °C/19.8 to 24.5 kbar, supported by abundant exsolution microstructures in garnet and clinopyroxene. Zircon U-Pb dating of the metagabbros and a granitic dike cross-cutting the metamorphic layering of the metagabbro constrain deformation and eclogite-facies metamorphism to >2.47 Ga. This finding implies that Archean oceanic crust was subducted to at least 65 to 70 km at the end of the Archean. Together with other asymmetric subduction records in the COB, it is inferred that modern-style plate tectonics evidenced by deep and asymmetric subduction along the circa 1,600-km-long orogen was operating at least by the end of the Archean era, when the planet was making a transition to the Proterozoic, witnessing the Great Oxidation Event, widespread emergence of continents, and development of crown node eukaryotic species on a more habitable planet.

The forces behind plate tectonics play a part in determining nearly everything about Earth, from its climate to the evolution of life. Since the early twenty-first century, geologists have been gathering data in search of answers as to when and how plate tectonics began. Hidden history Since the 1960s, geoscientists have recognized that Earth's outer shell - the lithosphere - is not one single solid piece, but a series of rocky plates that jostle against each other and gradually change position. When Earth formed 4.5 billion years ago, it was much hotter than today: the newborn Earth probably had a magma ocean ratherthan a solid surface, perhaps something similar to the planet 55 Cancri e, which has been studied by the James Webb Space Telescope. Some episodes of subduction might have been triggered by meteorite impacts, according to simulations of such strikes7.