Mineral chemistry (EMPA) of monazites in metamorphic rocks from Edea region: implications of the monazite chemistry on the metamorphic evolution of the Nyong Complex

Jean-Lavenir, Ndema Mbongué; Sigue, Cyrille; Paul, Nzenti Jean; Suh, Cheo Emmanuel

doi:10.1007/s12517-022-10924-7

Cited by 5 publications

(1 citation statement)

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“…Monazite (Nd, Ce, La, Y, Th) PO 4 is a phosphate of the group of rare earth metals usually found as a comparatively rare accessory mineral in granitic rocks and pegmatites. It is a reddish-brown phosphate mineral that contains rare earth elements, primarily neodymium (Nd) [52]. Neodymium expresses spectral diagnostic absorption features around 0.53 µm, 0.74 µm, 0.80 µm, and 0.87 µm [51].…”

Section: Geological and Tectonic Settingmentioning

confidence: 99%

Unexpected Expansion of Rare-Earth Element Mining Activities in the Myanmar–China Border Region

Chinkaka,

Klinger,

Davis

et al. 2023

Remote Sensing

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Mining for rare earth elements is rapidly increasing, driven by current and projected demands for information and energy technologies. Following China’s Central Government’s 2012 strategy to shift away from mining in favor of value-added processing, primary extraction has increased outside of China. Accordingly, changes in mineral exploitation in China and Myanmar have garnered considerable attention in the past decade. The prevailing assumption is that mining in China has decreased while mining in Myanmar has increased, but the dynamic in border regions is more complex. Our empirical study used Google Earth Engine (GEE) to characterize changes in mining surface footprints between 2005 and 2020 in two rare earth mines located on either side of the Myanmar–China border, within Kachin State in northern Myanmar and Nujiang Prefecture in Yunnan Province in China. Our results show that the extent of the mining activities increased by 130% on China’s side and 327% on Myanmar’s side during the study period. We extracted surface reflectance images from 2005 and 2010 from Landsat 5 TM and 2015 and 2020 images from Landsat 8 OLI. The Normalized Vegetation Index (NDVI) was applied to dense time-series imagery to enhance landcover categories. Random Forest was used to categorize landcover into mine and non-mine classes with an overall accuracy of 98% and a Kappa Coefficient of 0.98, revealing an increase in mining extent of 2.56 km2, covering the spatial mining footprint from 1.22 km2 to 3.78 km2 in 2005 and 2020, respectively, within the study area. We found a continuous decrease in non-mine cover, including vegetation. Both mines are located in areas important to ethnic minority groups, agrarian livelihoods, biodiversity conservation, and regional watersheds. The finding that mining surface areas increased on both sides of the border is significant because it shows that national-level generalizations do not align with local realities, particularly in socially and environmentally sensitive border regions. The quantification of such changes over time can help researchers and policymakers to better understand the shifting geographies and geopolitics of rare earth mining, the environmental dynamics in mining areas, and the particularities of mineral extraction in border regions.

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Section: Geological and Tectonic Settingmentioning

confidence: 99%