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Recycling of molybdenum isotopes in continental subduction zones remains debated. In this contribution, we re‐visit the Mo isotope compositions of the Sailipu post‐collisional ultrapotassic rocks in the Himalaya‐southern Tibet orogen. These ultrapotassic rocks have very varying δ98/95Mo values of −0.66 to −0.07‰ and Mo/Ce ratios of 0.0008–0.005, which are lower than those of mid‐ocean ridge basalts (MORB; δ98/95Mo = −0.20 ± 0.06‰, and Mo/Ce = 0.03) and oceanic subduction‐related (i.e., mantle source involving fluids, residual slab, or oceanic sediments) magmatic rocks (e.g., modern arc lavas, Cenozoic OIB‐type basalts in eastern China and the central Mariana Trough basalts in the back‐arc basin, syn‐collisional andesitic rocks in southern Tibet). Combined with the light Mo isotopes of the Himalayan schists and gneisses, we suggest that the light Mo isotopic signature of the Sailipu ultrapotassic rocks is derived from subducted Indian continental crust. This is consistent with the extremely low δ11B (−17.4 to −9.7‰) and B/Nb (0.16–1) values and enriched Sr‐Nd‐Pb isotopes of the Sailipu ultrapotassic rocks. Thus, this study reveals the recycling of light Mo‐B isotopes during continental subduction and demonstrates that Mo‐B isotopes can effectively distinguish between continental and oceanic subduction. Plain Language Summary: Mo isotope systematics have been widely applied in the study of tracing recycled crustal materials, and abundant researches have proposed that heavy Mo isotopic compositions of arc‐mafic magma can be ascribed to slab‐dehydrated fluids. However, in continental subduction zones, the origin of the light Mo isotopes of post‐collisional mafic rocks (oceanic sediments during prior oceanic subduction vs. subducted continental crust) remains controversial, hindering our understanding of the recycling of continental crustal materials. In this study, we report new Mo isotope data of post‐collisional ultrapotassic rocks in the Lhasa block of the southern Tibetan plateau. We have used Mo isotope data along with B‐Sr‐Nd‐Pb isotopes of these ultrapotassic rocks, in combination with Mo‐B‐Sr‐Nd‐Pb isotopes of the Himalayan crustal rocks (e.g., gneisses and schists) to trace the crustal components in the post‐collisional mantle beneath southern Tibet. We concluded that the light Mo and B isotope compositions in southern Tibet were derived from subducted Indian continental crust rather than Neo‐Tethyan oceanic sediments. Thus, this study not only reveals the recycling of light Mo‐B isotopes in this typical collision orogen (i.e., Himalaya‐Tibet orogen) but also shows the potential in discriminating between oceanic subduction metasomatism and continental subduction metasomatism. Key Points: Post‐collisional ultrapotassic rocks in southern Tibet have extremely light Mo and B isotope compositionsThese light Mo‐B isotope features are derived from subducted Indian continental crustMo‐B isotopes have the potential to discriminate between oceanic and continental subduction [ABSTRACT FROM AUTHOR]

Species diversity is high in the Himalaya-Hengduan Mountains, particularly at the edges characterized by deep ravines and "sky islands". Studies focused on sky-island species are sparse and the patterns observed in response to both geographic and climatic factors are inconsistent. Here phylogeographic and phylogenetic analyses of Gaultheria nummularioides, a species originating in the late Pliocene with its main distribution in the Himalaya-Hengduan Mountains, were conducted to reveal the pattern of genetic dynamics in response to physical geography, glacial fluctuations, and monsoons. We found that in this species genetic variation is higher among populations than within populations, with a significant phylogeographic boundary between the central Himalaya and the eastern Himalaya and the Hengduan Mountains. We also found a high incidence of private alleles, possibly associated with strong habitat isolation. The phylogeographic pattern recovered is consistent with populations in glacial refugia that have experienced expansion after glaciation. The divergence times of most haplotypes coincide with the time of the weakening of the Asian monsoon in these regions. Models of geographic range size showed a significant decrease from the Last Interglacial through the Last Glacial Maximum to the Current, and a predicted increase from the Current to the year 2070. Our study provides insights for understanding speciation among sky islands in this region. [ABSTRACT FROM AUTHOR]

The last taxonomic revision of Gaultheria series Trichophyllae (Ericaceae), a clade of high-elevation species endemic to the Himalaya- Hengduan Shan region of east-central Asia, was published in 1941. Since then, a number of new species have been described and other taxonomic changes have occurred in the group, prompting the need for a comprehensive revision. The present treatment of the series comprises 21 species, including Gaultheria xbiluoensis, a newly described hybrid between G. crassifolia and G. major. A key to species and species descriptions is provided, and lectotypes are newly designated for G. cardiosepala, G. gonggashanensis, G. marronina, and G. stenophylla. [ABSTRACT FROM AUTHOR]

The question of whether subducted continental crust can be recycled into post-collisional magmatism in continental collisional zones remains controversial. Post-collisional mantle-derived ultrapotassic rocks are widespread in western part of central Lhasa block (WCL) of the Tibet-Himalaya orogen and show arc-type trace-element signatures and very enriched Sr Nd isotopes, which have been explained by the recycling of subducted Indian continental crust. However, due to the lack of late Cretaceous mafic magmatism in the WCL, the nature of the ancient subcontinental lithospheric mantle (SCLM) beneath the WCL has not been well constrained. It is therefore still unclear whether the enriched components of these ultrapotassic rocks were derived from subducted Indian continental crust or inherited from the ancient SCLM. Here we report the mafic dykes from the TangraYumco area in the WCL, which formed at ∼90 Ma (whole-rock 40Ar 39Ar, and zircon and titanite U Pb ages). The diabase-porphyrites and diorite-porphyrites are similar to intraplate Nb-enriched basalts and magnesium adakitic rocks, respectively. This rock association reveals the lithospheric foundering process. Furthermore, the diabase-porphyrites generated by the interaction between the ancient SCLM and asthenosphere provide important constraints on the nature of the ancient SCLM, which shows distinct Nd isotopes to the post-collisional ultrapotassic rocks. In addition, the NW Lhasa block was in a rear-arc environment since the late Cretaceous and thus this SCLM was not significantly influenced by the ongoing northward subduction of the Indus-YarlungZangbu Neo-Tethys ocean. Finally, we propose that the post-collisional ultrapotassic rocks cannot be sourced from the ancient SCLM, but instead were derived from a relatively depleted mantle (e.g., juvenile lithospheric mantle) metasomatized by subducted Indian continental crust. Thus, this study confirms the recycling of subducted continental materials in continental collisional orogens. • The ca. 90 Ma mafic dykes in central Lhasa block of southern Tibetan plateau reveal the lithospheric foundering process. • The diabase-porphyrites formed by asthenosphere-ancient lithospheric mantle interaction constrain the nature of this SCLM. • This study confirms the recycling of subducted continental materials in continental collisional orogens. [ABSTRACT FROM AUTHOR]

Gaultheria griffithiana is an evergreen shrub in the family Ericaceae. It is used as a source of the Chinese traditional medicine, Tougucao, with distribution of the junction of eastern Himalaya and Hengduan Mountain. The chloroplast genome of G. griffithiana is 175,649 bp in length with 135 genes, including eight rRNA genes, 39 tRNA genes, and 85 protein-coding genes. Phylogenetic analysis has converged on the placement of G. griffithiana as sister to G. praticola, G. nummularioides, and G. hookeri within the Leucothoides clade of Gaultheria in this study. [ABSTRACT FROM AUTHOR]

The role played by felsic igneous magmatism in crustal differentiation is of importance for the evolution and habitability of Earth system. However, the petrogenesis of felsic rocks and their genetic links to mafic magmas remain controversial, hindering our understanding of crustal differentiation processes. Cenozoic post-collisional felsic potassic rocks occur widely in the well-known Himalaya-Tibet orogen and are intimately associated, in space and time, with mantle-derived ultrapotassic rocks, which thus provide a clear case study to investigate the genesis of felsic rocks and their genetic relationship with mafic rocks. Here we report zircon U Pb ages and Hf O isotopes, mineral major elements, and whole-rock elemental and Sr-Nd-Pb isotopic compositions for the TangraYumco high-silica potassic rocks (trachytes) in central Lhasa block of southern Tibet. The results, combined with literature data of the TangraYumco ultrapotassic rocks, can help better illuminate their genesis and the role of ultrapotassic rocks in their generation. The trachytes erupted in the Miocene (~13 Ma), coeval with ultrapotassic lavas in this area. They have very enriched Sr-Nd-Pb-Hf-O isotope compositions similar to those of ultrapotassic rocks. However, they display more fractionated LREEs (light rare earth elements) than ultrapotassic rocks. The trachytes also show nearly constant Y and Yb contents with increasing SiO 2. This indicates that they were not derived by fractional crystallization from ultrapotassic magmas or by mixing between ultrapotassic and ancient crust-derived felsic magmas. Instead, given their lower LREE contents than ultrapotassic rocks and occurrence of clinopyroxene antecrysts, we suggest that the TangraYumco trachytes were likely produced by remelting of newly-formed, Sr-Nd-Pb isotopically enriched, and K-rich cumulates that crystallized from ultrapotassic magmas. Moreover, taking into account regional magmatism and tectonics, we propose that the TangraYumco-Xuruco post-collisional coeval magmatism and rift system represent a response to tearing of subducted Indian continental slab. Finally, in combination with the nature of post-collisional magmatism in the Lhasa block, we suggest that in addition to reworking of juvenile and ancient crust, underplating of post-collisional mafic magmas and remelting of their cumulates could be an important way to differentiate continental crust in collisional orogeny zones. • TangraYumco Miocene trachytes have a K-rich, isotopically enriched crustal origin. • The source components are cumulates that crystallized from ultrapotassic magmas. • TangraYumco coeval rift and magmatism are a response to Indian continental tearing. • Cumulate melting can differentiate continental crust in collisional orogenic zones. [ABSTRACT FROM AUTHOR]

Abstract: Phylogenetic relationships of 84 samples representing 30 species in the core East Asian clade of the wintergreen group of Gaultheria (Angiospermae: Ericaceae: Gaultherieae) were estimated from separate and combined DNA sequence data from five genic regions (ITS, matK, rpl16, trnL–trnF, and trnS–trnG) with parsimony, likelihood and Bayesian analyses. Two major clades were recovered, one comprising several sections and series with leaves generally more than 1cm long [the ser. Leucothoides sensu lato (s.l.) clade] and another comprising the species of ser. Trichophyllae, with leaves generally less than 1cm long. The ITS region yielded little phylogenetic resolution, whereas in the combined chloroplast analysis the samples from individual morphospecies in both clades were often nonmonophyletic. This was postulated to result from reticulate evolution in the ser. Leucothoides s.l. clade, particularly in two specific cases of hybridization and a crown clade with likely chloroplast capture following localized introgression. In the ser. Trichophyllae clade, such nonmonophyly was largely attributed to cryptic species and character convergence resulting at least partly from extreme morphological reduction. The relatively low-elevation habitats in which the species of the ser. Leucothoides s.l. clade generally grow are thought to have promoted opportunities for sympatry and reticulation, whereas the high-alpine habitats of ser. Trichophyllae are more likely to have spawned isolated populations and narrow endemism. As in other Sino-Himalayan plant groups, overall low sequence divergence and reticulate evolution suggest rapid radiation in the core East Asian clade of Gaultheria. [Copyright &y& Elsevier]

Although machine learning (ML) techniques are increasingly popular in water resource studies, they are not extensively utilized in modeling snowmelt. In this study, we developed a model based on a deep learning long short-term memory (LSTM) for snowmelt-driven discharge modeling in a Himalayan basin. For comparison, we developed the nonlinear autoregressive exogenous model (NARX), Gaussian process regression (GPR), and support vector regression (SVR) models. The snow area derived from moderate resolution imaging spectroradiometer (MODIS) snow images along with remotely sensed meteorological products were utilized as inputs to the models. The Gamma test was conducted to determine the appropriate input combination for the models. The shallow LSTM model with a hidden layer achieved superior results than the deeper LSTM models with multiple hidden layers. Out of seven optimizers tested, Adamax proved to be the aptest optimizer for this study. The evaluation of the ML models was done by the coefficient of determination (R2), mean absolute error (MAE), modified Kling–Gupta efficiency (KGE'), Nash–Sutcliffe efficiency (NSE), and root-mean-squared error (RMSE). The LSTM model (KGE' = 0.99) enriched with snow cover input achieved the best results followed by NARX (KGE' = 0.974), GPR (KGE' = 0.95), and SVR (KGE' = 0.949), respectively. The outcome of this study proves the applicability of the ML models, especially the LSTM model, in predicting snowmelt driven discharge in the data-scant mountainous watersheds. [ABSTRACT FROM AUTHOR]

Gaultheria series Trichophyllae Airy Shaw is an angiosperm clade of high-alpine shrublets endemic to the Himalaya-Hengduan Mountains and characterized by recent species divergence and convergent character evolution that has until recently caused much confusion in species circumscription. Although multiple DNA sequence regions have been employed previously, phylogenetic relationships among species in the group have remained largely unresolved. Here we examined the effectiveness of the plastid genome for improving phylogenetic resolution within the G . series Trichophyllae clade. Plastid genomes of 31 samples representing all 19 recognized species of the series and three outgroup species were sequenced with Illumina Sequencing technology. Maximum likelihood (ML), maximum parsimony (MP) and Bayesian inference (BI) phylogenetic analyses were performed with various datasets, i.e., that from the whole plastid genome, coding regions, noncoding regions, large single-copy region (LSC) and inverted-repeat region a (IRa). The partitioned whole plastid genome with inverted-repeat region b (IRb) excluded was also analyzed with ML and BI. Tree topologies based on the whole plastid genome, noncoding regions, and LSC region datasets across all analyses, and that based on the partitioned dataset with ML and BI analyses, are identical and generally strongly supported. Gaultheria series Trichophyllae form a clade with three species and one variety that is sister to a clade of the remaining 16 species; the latter comprises seven main subclades. Interspecific relationships within the series are strongly supported except for those based on the coding-region and IRa-region datasets. Eight divergence hotspot regions, each possessing >5% percent variable sites, were screened across the whole plastid genome of the 28 individuals sampled in the series. Results of morphological character evolution reconstruction diagnose several clades, and a hypothesis of adaptive evolution for plant habit is postulated. [ABSTRACT FROM AUTHOR]