A study of mirror-shaped bronze vessels of Northeast China and the Korean peninsula

2017 ◽  
Vol 20 ◽  
pp. 56-87
Author(s):  
Kang won Oh ◽  
2016 ◽  
Vol 139 (3-4) ◽  
pp. 609-622 ◽  
Author(s):  
Zhenju Chen ◽  
Xingyuan He ◽  
Nicole K. Davi ◽  
Xianliang Zhang

2021 ◽  
Author(s):  
Hyunseong Kim ◽  
Youngjun Lee ◽  
Doyoung Kim ◽  
Changyeol Lee

<p>Quaternary Intraplate volcanoes are sparsely distributed in Northeast Asia including Northeast China and Korean Peninsula and roles of the stagnant Pacific plate in the volcanoes have been studied. Recent geochemical studies suggest that the hydrated mantle in the mantle transition zone was incorporated in the wet plumes that were generated from the hydrated layer atop the stagnant slab, and the ascending wet plumes experienced partial melting in the shallow asthenosphere. To quantitatively evaluate the incorporation of the mantle in the transition zone into the wet plumes and their partial melting in the asthenosphere, we conducted a series of two-dimensional thermochemical numerical models by including the olivine-wadsleyite phase transition at the 410km discontinuity. The buoyancy is controlled by temperature, bound-water content and mineral phase. Viscosity reduction by the bound-water is added to the temperature-dependent viscosity. Particle tracers are used to track the incorporation of the mantle in the transition zone into the wet plumes. We vary the Clapeyron slope of the phase transition and water distributions in the mantle transition zone and hydrated layer of the stagnant slab to evaluate their effects on the behavior of the wet plumes. Results show that multiple wet plumes generated from atop the stagnant slab incorporate the hydrated mantle in the transition zone. Due to the endothermic phase transition at the 410 km discontinuity, the ascending wet plumes are retarded and laterally migrated beneath the 410 km discontinuity for several million years, and enter the overlying asthenosphere as merged large wet plumes. The ascending merged wet plumes laterally spread beneath the thermal lithosphere and experience partial melting, consistent with the interpretation based on the geochemical studies. The spacing of the merged wet plumes (~440 km) caused by the phase transition at the 410 km discontinuity is consistent with the sparse volcano distribution in Northeast China and Korean Peninsula.</p>


2020 ◽  
Vol 85 ◽  
pp. 183-196
Author(s):  
Y Sun ◽  
J Liu ◽  
Q Yao ◽  
J Jin ◽  
X Liu ◽  
...  

Viruses are the most abundant and ubiquitous biological entities in various ecosystems, yet few investigations of viral communities in wetlands have been performed. To address this data gap, water samples from 6 wetlands were randomly collected across northeast China; viruses in the water were concentrated by sequential tangential flow filtration, and viral communities were assessed through randomly amplified polymorphic DNA-PCR (RAPD-PCR) with 4 decamer oligonucleotide primers. Principal coordinate analysis and hierarchical clustering analysis of the DNA fingerprints showed that viral community compositions differed among the water samples: communities in the 2 coastal wetlands were more similar to each other than to those in the 4 freshwater wetlands. The Shannon-Weaver index (H) and evenness index (E) of the RAPD-PCR fingerprint also differed among the 6 wetlands. Mantel test revealed that the changes in viral communities in wetland water were most closely related to the water NH4+-N and inorganic C content, followed by total K, P, C and NO3--N. DNA sequence analysis of the excised bands revealed that viruses accounted for ~40% of all sequences. Among the hit viral homologs, the majority belonged to the Microviridae. Moreover, variance partitioning analysis showed that the viral community contributed 24.58% while environmental factors explained 30.56% of the bacterial community variation, indicating that the bacterial community composition was strongly affected by both viral community and water variables. This work provides an initial outline of the viral communities from different types of wetlands in northeast China and improves our understanding of the viral diversity in these ecosystems.


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