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Patterns of species richness are commonly linked to life history strategies. In diatoms, an exceptionally diverse lineage of photosynthetic heterokonts important for global photosynthesis and burial of atmospheric carbon, lineages with different locomotory and reproductive traits differ dramatically in species richness, but any potential association between life history strategy and diversification has not been tested in a phylogenetic framework. We constructed a time-calibrated, 11-gene, 1151-taxon phylogeny of diatoms – the most inclusive diatom species tree to date. We used this phylogeny, together with a comprehensive inventory of first–last occurrences of Cenozoic fossil diatoms, to estimate ranges of expected species richness, diversification and its variation through time and across lineages. Diversification rates varied with life history traits. Although anisogamous lineages diversified faster than oogamous ones, this increase was restricted to a nested clade with active motility in the vegetative cells. We propose that the evolution of motility in vegetative cells, following an earlier transition from oogamy to anisogamy, facilitated outcrossing and improved utilization of habitat complexity, ultimately leading to enhanced opportunity for adaptive divergence across a variety of novel habitats. Together, these contributed to a species radiation that gave rise to the majority of present-day diatom diversity.

Formation of the Tibetan Plateau is generally ascribed to the Cenozoic India–Asia collision. However, the origin of along-strike deformation of the Indian mantle lithosphere, especially beneath the eastern Tibetan Plateau region, and its effect on the plateau’s eastward growth remain unclear. Here, we conduct multiscale seismic tomography to provide a revised structure of the Indian mantle lithosphere beneath the eastern Tibetan Plateau region. Our results demonstrate that the Indian mantle lithosphere is currently torn vertically along ~26° N, with its northern portion shallowly subducting northeastwards and the southern portion steeply subducting eastwards into the mantle transition zone. Analysis of tectonic and magmatic records is consistent with advancing and retreating migration of the slab tear after about 50 Myr ago. We suggest that the rigid Yangtze cratonic lithosphere tore the intruding cratonic Indian mantle lithosphere approximately 35 Myr ago, resulting in diverging shallow subduction. The subsequent Miocene rollback of the southeastern Indian mantle lithosphere is proposed to induce a giant turbo-engine-like flow that caused clockwise rotation of the plateau crust and underlying mantle around the eastern syntaxis, leading to differential eastward growth of the Tibetan Plateau. The Cenozoic eastward growth of the Tibetan Plateau can be explained by slab tear and the resulting mantle flow beneath the eastern region, according to analysis of seismic tomography, tectonic and magmatic records of the Indian mantle lithosphere.

The Lhasa‐Qiangtang collision closed the Meso‐Tethys Ocean, but the exact timing of this event remains hotly debated. Here, we present geochronological and paleomagnetic analyses conducted on Cretaceous volcanics from western Qiangtang to constrain the Lhasa‐Qiangtang collision in western Tibet. Our investigations yield a paleolatitude of ∼30.5 ± 5.0°N for western Qiangtang during ca. 110–100 Ma. A reanalysis of previously acquired Mesozoic‐Cenozoic paleomagnetic data from western Qiangtang suggests a stationary position during ca. 136–34 Ma. Examination of paleomagnetic data from western Lhasa reveals a significant reduction in northward paleolatitudinal motion during the Early Cretaceous, dropping from ∼12.3 cm/yr to nearly zero. Integration of our paleomagnetic findings with available geological records has led to conclude that the Lhasa‐Qiangtang collision in western Tibet occurred at ca. 132 Ma. Additionally, we infer that crustal shortening on the order of ∼1,000 km happened between Lhasa and Qiangtang during the Early Cenozoic. Plain Language Summary The Tibetan Plateau comprises multiple different blocks, which originated from the Gondwana in the southern hemisphere. Their convergence histories toward Euraisa have changed the global land‐sea distributions since the Late Paleozoic. The time at which the Lhasa block, one of the Tibetan blocks, accreted to the Qiangtang block to the north remains poorly constrained. In this work, we provide robust data suggesting a latitude of ∼30.5 ± 5.0°N for western Qiangtang during the Early Cretaceous (ca. 110–100 Ma). We also compiled the available latitudinal data from western Tibet in combination with geological observations. We suggest Lhasa collided with Qiangtang during 132 million years ago in western Tibet. Significant shortening of the continental crust by ∼1,000 km between the Lhasa and Qiangtang blocks occurred after their collision. Key Points Western Qiangtang had a paleolatitude of ∼30.5 ± 5.0°N at ca. 110–100 Ma A substantial decrease in the paleolatitudinal motion of western Lhasa occurred in the Early Cretaceous The Lhasa‐Qiangtang collision in western Tibet occurred at ca. 132 Ma

Distinguishing the independent contributions of tectonic denudation and climate‐driven erosion on the production and supply of clastic materials of Chinese eolian deposits is important in understanding the dynamic links between global climate changes, tectonics, and Asian dust emission. Here, multi‐proxy rock magnetic records of detrital fractions of Chinese eolian deposits since ∼6 Ma, combined with further comparison with dust accumulation rates and geochemical data, suggest that limited production and supply of clastic materials of Chinese eolian deposits were observed between 5.6 and 4.4 Ma in a warmer climate, and thereafter an increasing trend is evident during a cooler world. We propose that intense physical erosion under cooler conditions caused increasing production of fresh detrital components, exerting dominant influences on the sediment supply to Asian eolian deposits. This study provides direct evidence of dynamic coupling between intensified physical erosion and Asian dust activity under late Cenozoic global cooling. Plain Language Summary The dust cycle is an important component of the Earth's climate system. Glacial erosion and tectonic denudation are usually regarded as two principal factors controlling the production and supply of clastic materials of Asian eolian deposits. To date, however, the dynamic coupling between intensified glacial erosion and tectonic denudation and Asian dust activity remains challenging and has rarely been reported. Multi‐proxy lithogenic magnetic records, combined with a synthesis of published dust accumulation rates and geochemical data, demonstrate that temporal variations in the production and supply of lithogenic materials of Chinese eolian deposits over the past 6 Ma appear to be closely coupled to the global temperature and climate state. Intense glacial erosion and frost‐weathering processes during late Cenozoic global cooling led to increased production and supply of fresh detrital material from the high mountains. The significant role of global cooling in the production and release of Asian dust materials is underscored. The cryospheric control on Asian dust activity challenges previously dominant views that dryland dynamics alone exerted primary influences on atmospheric dust formation. Key Points The production and supply of clastic materials of eolian deposits were limited during 5.6–4.4 Ma and increased toward a cooler world Intense glacial erosion and frost‐shattering processes in a cold climate caused increasing production and supply of clastic materials A dynamic coupling exists between intensified physical erosion and Asian dust activity under late Cenozoic global cooling conditions

The uplift and deformation styles of the Tibetan Plateau have been long debated on stepwise growth and crustal channel flow. Here, we offer new insight into this issue by constraining the pulsed exhumation history of the Yalong thrust belt in eastern Tibet, using apatite and zircon (U–Th)/He data from three ∼1 km vertical transects. The results revealed two rapid cooling pulses in the Late Oligocene (∼24 Ma, 50°C/m.y.) and the Middle Miocene (17–14 Ma, 35 °C/m.y.), respectively, which we ascribe to the staged‐thrusting faulting of this belt. These thrust faulting events indicated upward and eastward growth of the Tibetan Plateau, further suggested that the high topographic relief across the Yalong thrust belt mainly formed (at least) since the Late Oligocene. The available documents from paleoaltimetry, basin sediment accumulation, and thermochronometers and our new results reveal a regional‐scale stepwise propagation pattern of tectonic deformation during the Middle–Late Cenozoic in eastern Tibet. Plain Language Summary The role of faulting in crust thickening has been one of the main controversies in the formation and evolution of the Tibetan Plateau. The Yalong thrust belt in eastern Tibet is a major Cenozoic structure with a 1.8–2.4 km topographic step, and its deformation processes are closely associated with the Cenozoic eastward plateau growth. In this study, we report 79 apatite and 78 zircon (U–Th)/He (AHe and ZHe) ages of 26 granitoid samples from three ∼1 km vertical transects. We suggest that the Yalong thrust belt underwent two rapid cooling (exhumation) pulses in the Late Oligocene (∼24 Ma, 50°C/m.y.) and the Middle Miocene (17–14 Ma, 35°C/m.y.), respectively. These pulses of exhumation and uplift along the Yalong thrust belt contributed to the development of the current morphology across eastern Tibet. Integrating previous findings and those reported in our study allow us to propose a regional‐scale stepwise propagation pattern of tectonic deformation during the Middle–Late Cenozoic in eastern Tibet. We suggest that the dynamic development of the deformation pattern may have been driven by the northward indentation of the Eastern Himalayan Syntaxis and the consequent lower crustal flow into southeastern Tibet. Key Points The Yalong thrust belt underwent two rapid cooling pulses in the Late Oligocene (∼24 Ma) and Middle Miocene (17–14 Ma) The topographic relief across the Yalong thrust belt is mainly the result of pulsed thrusting at least since 24 Ma A regional‐scale stepwise propagation pattern was proposed for the Middle–Late Cenozoic tectonic deformation in eastern Tibet

To provide constraints on the formation mechanisms of intracontinental volcanisms and intriguing lithospheric thickness variations in the East Sayan Mountains and surrounding areas, we stack P‐to‐s receiver functions to image the 410‐km and 660‐km discontinuities. Mantle transition zone (MTZ) thickening observed in a continuous area is attributable to ancient slab remnants, and Cenozoic volcanisms in the peripheral area can be explained by slab dehydration. The thinning of the MTZ in the Tuva‐Mongolian Massif can be explained by mantle upwelling branches induced by slab subduction. Our results reveal an approximately circular area in the MTZ that is significantly thicker than usual, suggesting the presence of detached mantle lithosphere in the form of a lithospheric drip extending to the MTZ. The presence of the drip is consistent with geochemical and lithospheric thickness observations, and the drip could be triggered by passage of a mantle plume currently located beneath western Lake Baikal.

The potential link between erosion rates at the Earth’s surface and changes in global climate has intrigued geoscientists for decades 1 , 2 because such a coupling has implications for the influence of silicate weathering 3 , 4 and organic-carbon burial 5 on climate and for the role of Quaternary glaciations in landscape evolution 1 , 6 . A global increase in late-Cenozoic erosion rates in response to a cooling, more variable climate has been proposed on the basis of worldwide sedimentation rates 7 . Other studies have indicated, however, that global erosion rates may have remained steady, suggesting that the reported increases in sediment-accumulation rates are due to preservation biases, depositional hiatuses and varying measurement intervals 8 – 10 . More recently, a global compilation of thermochronology data has been used to infer a nearly twofold increase in the erosion rate in mountainous landscapes over late-Cenozoic times 6 . It has been contended that this result is free of the biases that affect sedimentary records 11 , although others have argued that it contains biases related to how thermochronological data are averaged 12 and to erosion hiatuses in glaciated landscapes 13 . Here we investigate the 30 locations with reported accelerated erosion during the late Cenozoic 6 . Our analysis shows that in 23 of these locations, the reported increases are a result of a spatial correlation bias—that is, combining data with disparate exhumation histories, thereby converting spatial erosion-rate variations into temporal increases. In four locations, the increases can be explained by changes in tectonic boundary conditions. In three cases, climatically induced accelerations are recorded, driven by localized glacial valley incision. Our findings suggest that thermochronology data currently have insufficient resolution to assess whether late-Cenozoic climate change affected erosion rates on a global scale. We suggest that a synthesis of local findings that include location-specific information may help to further investigate drivers of global erosion rates. Reported acceleration of erosion in mountainous landscapes during the late Cenozoic is the result of combining thermochronology data with disparate exhumation histories, thereby converting spatial variations in erosion rates into temporal increases.

The modern high topography of the eastern Tibetan Plateau is drained by several of the largest rivers on Earth, and exerts a prominent influence on the Asian monsoon pattern. However, when the high terrain was formed remains highly debated. Here, we present detrital zircon U‐Pb ages that indicate a south‐flowing drainage system with distal headwaters passed through the Ninglang Basin at ca. 45 Ma. We advocate for early–middle Eocene surface uplift in the Gonjo Basin and areas to the west creating a southeast tilted topography across eastern Tibet. The termination of sedimentation at ca. 40 Ma implies that the river system had deviated from the Ninglang Basin, which we interpret as a result of rise of the Yalong‐Yulong thrust belt. Combined with other lines of evidence from previous studies, we support the establishment of moderate‐high elevation topography of eastern Tibet by late Eocene time. Plain Language Summary The eastern Tibetan Plateau has been a hotspot for studying the interactions between tectonic uplift, monsoon evolution, Asian biodiversity, and topographic development during continental collision. However, the timing of high‐elevation topography formation in eastern Tibet is a matter of debate, with age estimates ranging from middle Eocene to late Miocene. This directly leads to contradictory understanding of uplift processes and plateau growth mechanisms. Sedimentary basins are excellent recorders of past drainage pattern and tectonic process, while many Cenozoic basins in eastern Tibet have been understudied. Here we focus on the Ninglang Basin and carry out comprehensive research including stratigraphy, sedimentology, chronology, and provenance analysis. We indicate that the Ninglang Basin was mainly supplied by a south‐flowing exterior drainage system during the middle Eocene, implying the existence of a regional, low‐gradient landscape beveling to the southeast at that time. The extinction of this drainage system in late Eocene time likely means the initiation of the Yalong‐Yulong thrust belt, a major boundary fault system in eastern Tibet. Our study thus support that the topography of eastern Tibet has been elevated in the late Eocene. Key Points A large‐scale, south‐flowing fluvial system drained through the Ninglang Basin during the middle Eocene The demise of the Ninglang Basin in the late Eocene resulted from the uplift of the Yalong‐Yulong thrust belt The elevated terrain of eastern Tibet was initially formed in the late Eocene

The Paleogene sedimentary basins of southeastern Tibet record sediment dispersal patterns associated with crustal deformation during the early stages of the India–Asia collision. We present detrital zircon U–Pb geochronology, tourmaline geochemistry, and petrographic data from the Gonjo and Mangkang basins that suggest a reginal interconnected paleodrainage during the Paleocene–Eocene. Sediments were likely sourced from the distal Songpan–Ganzi and proximal northern Qiangtang terranes. Stratigraphic relationships and paleoelevation estimates support the interpretation of a paleodrainage system that may have extended toward the Lanping–Simao region and northern Vietnam. This system appears to have been disrupted in the late Eocene, possibly due to sinistral shearing along the Ailao Shan–Red River fault zone. These findings offer new insights into sediment routing and landscape evolution along the southeastern margin of the Tibetan Plateau during the early Cenozoic.

The Early Cenozoic sedimentary archives of Tibet are crucial for elucidating the geodynamic processes related to continental collision, particularly crustal deformation and shortening. However, the lack of a reliable chronostratigraphic framework for the Cenozoic sedimentary basins in central Tibet has hindered a comprehensive understanding of the influence of the continuous India‐Asia convergence process on the tectonic evolution of the Tibetan hinterland. Here, we report new magnetostratigraphic ages and paleomagnetic results for the Niubao Formation exposed in the northern bank of the Siling Co. Positive field tests and microscopic observations suggest that the remanence is primary. We determine that the depositional age of the measured section was between 59.2 and 48.6 Ma. Our results reveal that the paleogeographic location of the Bangong‐Nujiang Suture Zone during the Late Paleocene–Early Eocene was 25.4 ± 2.1°N, thus supporting the model of two‐stage collision between India and Asia. Plain Language Summary The tectono‐sedimentary evolution of the Cenozoic terrestrial sedimentary basins in the Tibetan Plateau was a long‐term response to Cenozoic continental collision and was critical for both constraining the amount of crustal shortening of the Asian continent and for paleogeographic reconstruction of the plateau. Nonetheless, the ages of the basins are controversial because of the discordance between radiometric dating results and paleontological ages. Siling Co is the geographic boundary between the Lunpola and Nima Basins, and the Niubao Formation is widely exposed on its northeastern margin, providing excellent research materials for studying the paleogeographic evolution of the plateau. Hence, we established a reliable magnetostratigraphic sequence of the Niubao Formation in northwestern Siling Co, combined with U‐Pb chronology, and constrained its age to 59.2–48.6 Ma. Our updated paleomagnetic results indicate that the paleolatitude of the Bangong‐Nujiang Suture Zone was 25.4 ± 2.1°N during the Late Paleocene–Early Eocene. Combined with the published paleomagnetic data from the intra‐oceanic arc, we suggest that the collision between the Asian and Indian continents had at least two stages and that the paleogeographic location of the collision was above 20°N. Key Points Detrital zircon U‐Pb ages and paleomagnetic polarity patterns indicate that the Niubao Formation was deposited at 59.2–48.6 Ma The Bangong‐Nujiang Suture Zone was located at 25.4 ± 2.1°N during the Paleocene–Eocene The amount of crustal shortening in the central Tibetan Plateau since 60 Ma is likely to be 780 ± 330 km