The Paleoproterozoic Lagoa do Riacho manganese deposit in the Borborema Province is central to unravelling genesis of deposits, redox evolution and genetic relationship West African Craton. With contents averaging 35 wt%, unit lithologically subdivided into oxidized silicate ores a garnetite (garnet-rich rocks) subgroup. ore consists mainly pyrolusite, manganese-oxyhydroxide spessartine. has rh...

The Xihuashan granitic complex (southern China) is mainly composed of coarse-grained porphyritic biotite granite (G–a), medium-grained porphyritic biotite granite (G–b), and mediumto fine-grained porphyritic biotite granite (G–c). The G–a granite is characterized by monazite-(Ce) and xenotime-(Y), in addition to commonly observed zircon and uranoan thorite. In the G–b and G–c intrusive units, m...

Massive, boudinaged, rose-coloured layers up to one metre in thickness composed of 60–80 vol% spessartine-rich garnet and 15–40 quartz occur high-pressure, garnet-mica schist on Margarita I...

the felsic pegmatitic rocks are exposed in the north of golpayegan. the dominate mineral assemblage is quartz, k-feldspar, plagioclase, muscovite, tourmaline and garnet. the elevated spessartine content of the garnets in the studied rocks along with their idiomorphic shape, the absence of resorption feature and garnet-free country rocks may point to their magmatic origin and crystallization at ...

In equatorial and tropical regions, supergene mineral deposits created during water/rock interactions are found. Simply put, these formed through the accumulation of low solubility ions or preservation primary minerals. The manganese (Mn) examples economic importance associated with chemical weathering processes. Brazil, Southern Brasilia Orogen (SBO) was generated collision between Paranapanem...

Abstract Garnet, an important mineral component in Earth's interior, usually contains minor water as structural OH, but experimental data on OH incorporation the a function of chemical and thermodynamic parameters remain rare. In particular, role oxygen fugacity ( f O 2 ) that is variable Earth has not been well assessed. We examine effects at 1–3 GPa 800–1000°C, by H‐annealing gem‐quality spes...

Located at the eastern segment of Tethyan Himalayan tectonic unit, Cuonadong leucogranites (muscovite granite and pegmatite) have a mineral assemblage quartz, plagioclase, alkali feldspar, as well muscovite garnet. Garnets in both pegmatite belong to almandine–spessartine solid solution, with minor andradite, grossular, pyrope, show specific Mn zoning relatively rim-ward depletion trend. Howeve...