538 research outputs found
Earliest Neoproterozoic (ca. 1.0 Ga) arc-back-arc basin nature along the northern Yunkai Domain of the Cathaysia Block: Geochronological and geochemical evidence from the metabasite
No full textAimei Zhang, Yuejun Wang, Weiming Fan, Yuzhi Zhang, Joe Yan
Permian arc–back-arc basin development along the Ailaoshan tectonic zone: Geochemical, isotopic and geochronological evidence from the Mojiang volcanic rocks, Southwest China
No full textEffects of Crustal Eclogitization on Plate Subduction/Collision Dynamics: Implications for India-Asia Collision
No full text2D thermo-mechanical models are constructed to investigate the effects of oceanic and continental crustal eclogitization on plate dynamics at three successive stages of oceanic subduction, slab breakoff, and continental subduction. Crustal eclogitization directly increases the average slab density and accordingly the slab pull force, which makes the slab subduct deeply and steeply. Numerical results demonstrate that the duration time from initial continental collision to slab breakoff largely depends on the slab pull force. Specifically, eclogitization of subducted crust can greatly decrease the duration time, but increase the breakoff depth. The detachment of oceanic slab from the pro-continental lithosphere is accompanied with obvious exhumation of the subducted continental crust and a sharp uplift of the collision zone in response to the disappearance of downward drag force and the induced asthenospheric upwelling, especially under the condition of no or incomplete crustal eclogitization. During continental subduction, the slab dip angle is strongly correlated with eclogitization of subducted continental lower crust, which regulates the slab buoyancy nature. Our model results can provide several important implications for the Himalayan-Tibetan collision zone. For example, it is possible that the lateral variations in the degree of eclogitization of the subducted Indian crust might to some extent contribute to the lateral variations of subduction angle along the Himalayan orogenic belt. Moreover, the accumulation of highly radiogenic sediments and upper continental crustal materials at the active margin in combination with the strong shear heating due to continuous continental subduction together cause rising of isotherms in the accretionary wedge, which facilitate the development of crustal partial melting and metamorphism
Origin of paleosubduction-modified mantle for Silurian gabbro in the Cathaysia Block: Geochronological and geochemical evidence
No full textDetrital Zircon U-Pb Geochronology and Lu-Hf Isotopic Compositions of the Wuliangshan Metasediment Rocks in SW Yunnan (China) and Its Provenance Implications
No full textThe Wuliangshan Group occurs to the east of the Lancang giant igneous zone in SW Yunnan, and is mainly composed of low-grade metamorphosed sedimentary rocks. The group has been considered as the syn-orogenic product of the Baoshan with Simao-Indochina blocks. However, its depositional time and provenance remain to be poorly constrained. This paper presents zircon U-Pb dating and Lu-Hf-isotopic data for five representative sandstone samples from the Wuliangshan Group. The detrital grains yield a major age-peak at similar to 259 Ma, and four subordinary age-peaks at similar to 1 859, similar to 941, similar to 788, and similar to 447 Ma, respectively. Our results suggest that the Wuliangshan metasedimentary sequence was deposited after Middle Triassic rather than previously-thought Cambrian. The detrital zircon age spectrum, along with in-situ Lu-Hf isotopic data suggest that the Wuliangshan Group might be a syncollisional sedimentary product related to the collision of Baoshan with Simao-Indochina blocks. It is inferred that the provenance of the Wuliangshan Group is mainly from the Simao/Yangtze blocks to the east rather than the Baoshan Block or Lancang igneous zone to the west
Development of inervertebral disc with functional nucleus pulposus for clinical application
No full textLower back pain caused by degenerative disc disease are getting more common in the
society. Current treatments available such as spinal fusion and artificial disc displacement
are able to relieve pain but fail to restore the function of intervertebral disc (IVD) and
associated with side effect. This has led to increase interest in tissue engineering of IVD
which aim to regenerate tissue’s native function through scaffold, cell and/or bioactive
agent. In this project, the role of nucleus pulposus chondrocyte (NPC), human
mesenchymal stem cell (hMSC) and growth factors in tissue engineering of nucleus
pulposus (NP) was investigated. NPC was sorted base on its physical size into smaller
and bigger size population. Through gene expression analysis and F-actin staining,
smaller size population was found to be able to form NP tissue construct that synthesis
higher level of major NP matrix component such as aggrecan and Type II Collagen.
Expansion of isolated patient’s cell has been the prerequisite for tissue engineering but it
is associated with de-differentiation. Therefore, the role of hMSC and effect of
encapsulated growth factors in forming NP tissue construct was studied. It was found that
hMSC was able to express more NP matrix when encapsulated with both transforming
growth factor beta 3 (TGF-β3) and platelet-derived growth factor-BB (PDGF-BB) than
each growth factor alone. The result of this project showed that cell encapsulating
hydrogel has the potential to be applied clinically with the injectable property of hydrogel
that allowed surgery to be carried out in minimal invasive way.Bachelor of Engineering (Chemical and Biomolecular Engineering
Micro-textural and fluid inclusion data constraints on metallic remobilization of the Ashele VMS Cu-Zn deposit, Altay, NW China
No full text
Geochronological and geochemical constraints on the metasomatised source for the Neoproterozoic (similar to 825 Ma) high-mg volcanic rocks from the Cangshuipu area (Hunan Province) along the Jiangnan domain and their tectonic implications
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