Petrogenesis of Late Cenozoic basaltic rocks from southern Vietnam

Lithos ◽  
2017 ◽  
Vol 272-273 ◽  
pp. 192-204 ◽  
Author(s):  
A-Rim An ◽  
Sung Hi Choi ◽  
Yongjae Yu ◽  
Der-Chuen Lee
Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 446 ◽  
Author(s):  
Long Yuan ◽  
Quanshu Yan ◽  
Xuefa Shi ◽  
Haitao Zhang ◽  
Xijun Liu

Shortly after the cessation of seafloor spreading, intraplate magmatism affected large areas in the South China Sea (SCS) region. The origin and geodynamic setting of the post-spreading volcanism is still in debate, for many previous studies have focused on petrogenesis and mantle source of the late Cenozoic basalts from the SCS region. In this study, we obtained in situ major element compositions (by using Electron microprobe analysis—EMPA) and trace element compositions (by using laser ablation inductively coupled plasma mass spectrometry— LA-ICP-MS) for minerals (clinopyroxenes (Cpx), plagioclases (Pl), and olivines (Ol)) hosted by late Cenozoic basaltic rocks from Thailand. The results showed that the olivines had forsterite contents between 60.12% and 84.74%. Clinopyroxene were diopside and augite, and they were enriched in light rare earth elements (LREEs) (LaN/YbN = 1.93–4.27) and depleted in large-ion lithophile elements (LILEs). Mineral compositions (mainly based on clinopyroxene) confirmed that these late Cenozoic basaltic rocks were of an intraplate affinity and were similar to contemporaneous basaltic fields in the SCS region (Southern Vietnam, Northern Hainan, and SCS seamounts). Plagioclases were predominantly labradorite, with a few andesine and bytownite, and they were enriched in LREEs and Ba, Sr, and Pb, and most of them exhibited strong positive Eu anomalies. The source lithology of Thailand basaltic rocks could be garnet pyroxenite. The mantle potential temperature beneath Thailand is in the range of 1448–1467 °C, which can be comparable to those beneath Southern Vietnam and Northern Hainan, indicating the Thailand basaltic rocks could be produced by the Hainan mantle plume. In addition, the crystallization temperature of clinopyroxenes (1145–1214 °C) and plagioclase (1067–1133 °C) and their composition characteristics indicate that the magmatic processes have a conspicuous characteristic of fast rate of magma upwelling. Thus, we proposed that the deep geodynamic setting of Thailand late Cenozoic basaltic rocks is similar to those of the whole SCS region, and Hainan mantle plume plays a significant role in the petrogenesis of these basaltic rocks.


2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Quanshu Yan ◽  
Xuefa Shi ◽  
Ian Metcalfe ◽  
Shengfa Liu ◽  
Taoyu Xu ◽  
...  

2014 ◽  
Vol 17 (3) ◽  
pp. 69-75
Author(s):  
K. Okamura ◽  
K. Watanabe ◽  
K. Yonezu ◽  
Huyen Thuong Dang ◽  
Du Cong Do ◽  
...  

The importance of REE for modern industries is proved by the high demand. The abundance of REE is richer than that of noble metals like gold or silver. However, supply sources are concentrated in China. The share of the product of REE was highest in 2009 (over 90%) and that is used as a national strategy.Mining industry in Vietnam is mainly developed in northern part. Deposits of principle metals are located around Hanoi, and REE deposits (Dong Pao) is also explored in Lai Chau Province. On the other hand, few bauxite mine is in southern Vietnam and the REE exploration is not conducted enough. Therefore, the study about REE in southern Vietnam is significant. Samples are from mainly basalt and granite. REE pattern, which is normalized by the abundance of chondrite, of basaltic rocks and laterites shows that is decreases monotony. That amount of REE is low (50-180ppm). REE pattern of magnetite rocks and laterites has no Eu and Ce anomaly. On the other hand, illuminate rocks and laterites have strong negative Eu anomaly. Clay minerals were observed by XRD analysis using hydraulic elutriation. The result of REE pattern and sequential extraction, it is indicated that the form of HREE is changed and adsorbed to clay and LREE is leached out. In tailing in Stop 16, it is observed that the concentration of HREE (about 3 times to 5 times than that of before washing). Eu anomaly is affected by reductive environment of the cooling of magma, and it is considered that Ce anomaly is occurred by the change of Ce form (Ce3+ to Ce4+). CeO2 is insoluble to water in the soil. From the XRD analysis, the cause of HREE concentration in water treatment is considered by the clay mineral


2010 ◽  
Vol 13 (3) ◽  
pp. 5-20
Author(s):  
Loc Duc Nguyen

The Vietnamese Catholic community is not only a religious community but also a traditional village with relationships based on kinship and/or sharing the same residential area, similar economic activities, and religious activities. In this essay, we are interested in examining migrating Catholic communities which were shaped and reshaped within the historical context of Viet Nam war in 1954. They were established after the migration of millions of Catholics from Northern to Southern Viet Nam immediately after Geneva Agreement in 1954. Therefore, by examining the particular structural traits of the emigration Catholic Communities we attempt to reconstruct the reproducing process of village structure based on the communities’ triple structure: kinship structure, governmental structure and religious organization.


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