Pantana phyllostachysae Chao ( P. phyllostachysae ) is a destructive leaf-eating pest that poses a significant threat to the health of bamboo forests and the bamboo industry. However, the spatial and temporal spread mechanisms of this pest are still unclear. To better understand and predict the spread of this pest, we used Sentinel-2A/B images from the pest detection period of 2018 to 2021, to identify association factors from five dimensions, including forest stand, meteorology, topography, pest sources, and human environment factors. The association factor sets for the spread of P. phyllostachysae were established under both existence and non-existence pest control scenarios. The extreme gradient boosting (XGBoost) model was employed to derive conversion rules for the respective spread models, enabling the determination of suitability probabilities for both healthy and damaged bamboo forests. These probabilities were then utilized in conjunction with cellular automata (CA) to simulate the spread of P. phyllostachysae under two scenarios. The results showed that the OA and Kappa reached more than 85% and 0.7 in both scenarios, respectively. Meanwhile, the division of pest control scenarios and the selection of XGBoost both help to improve the spreading simulation accuracy. Our models effectively coupled the research results of leaf hosts of different damage levels, simulated the spread of P. phyllostachysae , and identified the dynamic mechanisms of the pest's spread. These findings provide decision support for interrupting the spread path of the pest and achieving precise control, thus safeguarding forest ecological security.
Thickened crust is of great significance for tectonic evolution and mineralization and generally occurs in collisional orogenic belts. Whether accretionary orogenic belts, such as the Central Asian Orogenic Belt (CAOB), are able to create remarkably thickened crusts and what the mechanism is, remain to be determined. In the southwestern of CAOB, the Eastern Tianshan with broad magmatism and integrated arc-continental system is an excellent area for understanding the crustal evolution. Here, we report geochronological, geochemical and Nd-Hf-O isotope data for Middle Triassic Baishandong granites in the Eastern Tianshan, which exhibit three stages: Group 1 (ca. 237 Ma) granodiorites, Group 2 (ca. 234 Ma) monzogranites, and Group 3 (ca. 229 Ma) highly fractionated I-type granites. The Group 1 and 2 granites exhibit high-K, calc-alkaline, and metaluminous characteristics, weak negative Eu anomalies, and low (K2O+Na2O)/CaO and FeOT/MgO ratios with high Na2O/K2O, Sr/Y, and (La/Yb)N values and low MgO, Y, and Yb contents, which are indicative of adakitic affinity. The Group 3 rocks have extremely high SiO2 contents, notable Eu and Sr depletions, lower Mg# values, and the 'tetrad effect' of REEs, indicating that they are highly fractionated I-type granites. All the granites have similar depletion in Sr, Nd, Hf, and O isotope compositions (εNd(t) = 3.1–5.5, (87Sr/86Sr)i = 0.7036–0.7051, εHf(t) = 11.3–13.4, δ18O = 6.61–7.21) with young Nd, Hf second-stage model age (565–755 Ma, 425–541 Ma). It indicates that they are all the remelting of thickened juvenile lower crust that was initially derived from Neoproterozoic crust-mantle differentiation. Based on the discussion, we proposed that the granitic pluton intruded in an intraplate extensional setting, which indicates that thickened crust had existed before the Triassic and that the final amalgamation of the Paleo-Asian Ocean occurred in late Palaeozoic. Geochemical features indicate tectonic compression played a more important role in significant lower crust thickening.
The Seluohe Group in southern Jilin Province, northeastern China, is traditionally considered to be Mesoproterozoic in age and to represent a Grenville collisional belt at the northern margin of the North China craton, related to the assembly of the Rodinia supercontinent. Investigations indicate that this group is comprised of volcanic and sedimentary rocks that underwent amphibolite- to greenschist-facies metamorphism and intensive deformation. Zircon U-Pb ages indicate that the gneiss and amphibolites were formed in the Archean and underwent amphibolite metamorphism at ~2.5 Ga. However, rhyolite was erupted at 264 ± 10 Ma and andesites formed during the Late Jurassic at 169-162 Ma. These age data indicate that the Seluohe Group is composed by Late Paleozoic and Mesozoic volcanic rocks, with minor Archean metamorphic rocks. They are not a "group" in the stratigraphic sense, but represent a tectonic mélange. Interestingly, no Proterozoic rocks have been identified. Inherited zircons from volcanic rocks (rhyolite, andesite) and granitic gneiss provide no evidence of a Grenvillian collision. Therefore, the new geochronological data do not support the traditional view that Proterozoic tectono-magmatic events affected the northern margin of the North China craton; hence the conclusion that it took part in the formation and evolution of Rodinia during the Proterozoic is questioned. Ar-Ar mineral ages suggest that the Archean metamorphic rocks were later deformed at ~ 160 Ma, establishing a Jurassic deformational event in the area.
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