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The timing, kinematics, and geodynamic evolution of the India-Asia continental collision are crucial to understanding the geological and geomorphological evolution of the Himalayan-Tibetan orogen. However, the debate over how and when the collision occurred persists due to disputes concerning the reliability of paleomagnetic data obtained on both sides of the suture zone. This paper presents a comprehensive analysis and evaluation of paleomagnetic studies to address this controversial issue. The study focuses on well-preserved Cretaceous-Paleocene rocks from the Lhasa and Tethyan Himalaya (TH) terranes over the past two decades. We conclude that: (1) the paleomagnetic data of the Linzizong Group of the Lhasa Terrane and the Zongpu Formation of the TH are in their primary origin and can be used for tectonic reconstruction; (2) the Tethys Himalaya Basin (THB) was generated due to the rifting of the TH from Greater India before the Late Cretaceous; (3) the southern margin of Asia was aligned in the NW-SE direction before the India-Asia collision. The study suggests a quasi-synchronous multi-stage collision where the TH collided with the Trans-Tethyan subduction system in Late Cretaceous-Early Paleocene times (∼65 Ma), followed by collision with Asia at 56–59 Ma. Finally, the India Craton collided with the TH, resulting in the synchronous closure of the THB at approximately 40 Ma. [ABSTRACT FROM AUTHOR]

• Indian freshwater ecosystems are not well studied, are degraded due to expansive agriculture and are contaminated with pesticides. • Mesocosms identified malathion was the dominant stressor among co-occurring stressors. • In mesocosms malathion reduced richness, organism densities and caused community homogenisation. • Toxicology test comparisons between countries identify that Indian taxa may be relatively pesticide tolerant. Globally, river pesticide concentrations are associated with regional and local stream invertebrate diversity declines. Pesticides often co-occur with elevated nutrients (e.g. nitrogen and phosphorus) and sediments related to agriculture, making their individual effects difficult to disentangle. These effects are also less well studied in Asia, than in other geographic regions. Within Asia, India is one of the largest producers and users of pesticides and has approximately 60% of total land mass used for agriculture. Here we examine the responses of Indian river invertebrate communities subjected to malathion, nutrients, and sediment additions in a semi-orthogonal design, in three sequential (through time) short-term (120 h) mesocosm experiments. Additionally, a series of single-species toxicity tests were run that used 24 h exposure and 72 h recovery to examine the sensitivity of 13 local invertebrate taxa to malathion, and 9 taxa to cypermethrin, comparing these results to those from other biogeographic regions. Mesocosm results indicate that malathion exposure had a major effect compared to other stressors on communities, with a lesser effect of nutrients and/or sediments. In mesocosms, taxa richness, total abundance and the abundance of sensitive species all declined associated with malathion concentrations. Comparisons of organism sensitivities from other geographic locations and those in the current paper suggest taxa in India are relatively tolerant to malathion and cypermethrin. Our results further reinforce that the high observed aquatic pesticide concentrations known to occur in Asian freshwater ecosystems are likely to be negatively affecting biodiversity, homogenising biota towards those most stress tolerant. [ABSTRACT FROM AUTHOR]

Continental evolution is responsible for the evolution of orogenic belts and sedimentary basins. The India–Asia convergence during the late Mesozoic to Cenozoic and the resulting tectono-sedimentary processes in the Tibetan Plateau and and its environs are among the most spectacular manifestations of continental evolution and sedimentary basin formation in recent Earth history. The aim of this special issue is to explore continental evolution and sedimentary basins in central-southern Asia since the late Mesozoic, with a main focus on the India–Asia convergence and the resulting tectono-sedimentary, tectono-geomorphologic, and paleoclimatic/paleoenvironmental processes in the Tibetan Plateau and its environs during the late Cretaceous to Neogene. The issue comprises ten papers that address the significance of Continental Evolution and Sedimentary Basins of the Tibetan Plateau and its Environs since the middle Cretaceous, and that fall into three categories. (i) The first category addresses the paleogeography of the southern-central Tibetan Plateau during the Cretaceous to Paleogene. These studies decipher the multistage collision of India with Asia, the opening and closing of ocean basins, and the tectonic evolution of the major blocks (such as Tibetan Himalaya, Lhasa, and southern/western Qiangtang) and especially of the major Himalayan tectonostratigraphic units during the convergence history between India and Asia. (ii) The second category addresses the tectono-sedimentary and tectono-geomorphologic evolution of the eastern and northeastern margins of the Tibetan Plateau during the late Cretaceous to Neogene. (iii) The third and the final category addresses the tectono-sedimentary basin filling and/or paleoenvironmental processes during the late Eocene to Pliocene, which are recorded in the intermontane Kuche and Tajik basins in central Asia and thus may reflect the far-field influence of the post-collisional India–Asia convergence on these sedimentary basins. • Continental evolution is responsible for the evolution of orogenic belts and sedimentary basins. The India–Asia convergence during the late Mesozoic to Cenozoic and the resulting tectono-sedimentary processes in the Tibetan Plateau and and its environs are among the most spectacular manifestations of continental evolution and sedimentary basin formation in recent Earth history. • The paleogeography of the southern-central Tibetan Plateau during the Cretaceous to Paleogene was shaped by the multistage collision of Inida with Asia, the opening and closing of ocean basins, and the tectonic evolution of the major blocks (such as Tibetan Himalaya, Lhasa, and southern/western Qiangtang) and especially of the major Himalayan tectonostratigraphic units during the convergence history between India and Asia. • The India–Asia collision and ongoing convergence led to southeastward crustal extrusion, eastward and northeastward crustal growth and expansion of the Tibetan Plateau, and widespread crustal deformation surrounding the plateau. The concurrent uplift, denudation, and sedimentation have played important roles in shaping the mountain topography of the orogenic plateau margins. • The tectono-sedimentary filling and/or paleoenvironmental processes recorded in the intermontane Kuche and Tajik basins in central Asia during the late Eocene to Pliocene may reflect the far-field influence of the post-collisional India–Asia convergence on the sedimentary basins in central Asia and/or the interplay between tectonics and climate in the Asian interior. [ABSTRACT FROM AUTHOR]

Late Mesozoic uplift of the Gangdese arc occurred prior to the India–Asia collision and was important in the evolution of the Tibetan plateau, but the geodynamic mechanisms that drove this process are unclear. In this paper, we report geochronological, petrological, geochemical, and Sr–Nd–Hf isotopic data for intermediate–acidic igneous rocks from the western Gangdese arc. These igneous rocks were emplaced at 87–67 Ma and are characterized by enrichments in light rare earth and large-ion lithophile elements, depletions in high-field-strength elements, high (87Sr/86Sr) i ratios (0.7074–0.7116), and low ε Nd (t) (−7.5 to −4.1) and ε Hf (t) values (−16 to 0.8). These magmas were most likely derived by high-temperature (960–1200 °C) partial melting of the thickened crustal materials, with minor mantle input, related to post-orogenic lithospheric delamination. The increasing ε Nd (t) and ε Hf (t) values and decreasing initial Sr isotope ratios from the ca. 87 Ma diorites to ca. 67 Ma diorites and rhyolites indicate an increasing mantle contribution as delamination proceeded. Estimated pressure conditions for the high-Sr/Y gabbroic diorites indicates the magmas were derived from crust at pressures of up to 19 kbar (i.e., a depth of ~66 km). Therefore, the western Gangdese arc had been thickened during the Late Cretaceous, possibly due to the flat-slab subduction of Neo-Tethyan oceanic lithosphere and coeval collision of the Qiangtang–Lhasa terranes. • Intermediate–acidic rocks in the western Gangdese arc emplaced from 87 to 67 Ma. • Geochemical indices show they formed dominantly by melting of crustal material. • They formed at 960–1200 °C by melting of thickened crust with minor mantle input. • Nd-Hf-Sr isotopes indicate more mantle involvement following ongoing delamination. • Western Gangdese arc has been thickened during the Late Cretaceous. [ABSTRACT FROM AUTHOR]