scholarly journals Diamond nucleation barrier and melting relations for Ol-Opx-Cpx-Grt-carbonate system: syngenesis of diamond and silicate minerals

2019 ◽  
Keyword(s):  
Carbonate System ◽  
Diamond Nucleation ◽  
Silicate Minerals ◽  
Nucleation Barrier ◽  
Melting Relations

Electron energy-loss near-edge structure in silicate minerals

1992 ◽  
Vol 50 (2) ◽  
pp. 1258-1259
Author(s):  
D W McComb ◽  
R S Payne ◽  
P L Hansen ◽  
R Brydson
Keyword(s):  
Solid State ◽  
Energy Loss ◽  
Electron Energy ◽  
State Energy ◽  
Local Environment ◽  
Edge Structure ◽  
Silicate Minerals ◽  
Two Samples ◽  
Electron Energy Loss ◽  
Careful Processing

Electron energy-loss near-edge structure (ELNES) is an effective probe of the local geometrical and electronic environment around particular atomic species in the solid state. Energy-loss spectra from several silicate minerals were mostly acquired using a VG HB501 STEM fitted with a parallel detector. Typically a collection angle of ≈8mrad was used, and an energy resolution of ≈0.5eV was achieved.Other authors have indicated that the ELNES of the Si L2,3-edge in α-quartz is dominated by the local environment of the silicon atom i.e. the SiO4 tetrahedron. On this basis, and from results on other minerals, the concept of a coordination fingerprint for certain atoms in minerals has been proposed. The concept is useful in some cases, illustrated here using results from a study of the Al2SiO5 polymorphs (Fig.l). The Al L2,3-edge of kyanite, which contains only 6-coordinate Al, is easily distinguished from andalusite (5- & 6-coordinate Al) and sillimanite (4- & 6-coordinate Al). At the Al K-edge even the latter two samples exhibit differences; with careful processing, the fingerprint for 4-, 5- and 6-coordinate aluminium may be obtained.

USING SILICATE MINERALS AS MICROMODELS TO ACCESS THE RELATIONSHIP BETWEEN TRANSPORT AND REACTION AT THE PORE SCALE

2016 ◽  
Author(s):  
Heewon Jung ◽  
◽  
Alexis K. Navarre-Sitchler ◽  
Nathan Worts ◽  
Erica Block ◽  
...  
Keyword(s):  
Pore Scale ◽  
Silicate Minerals ◽  
The Relationship

Trace Element Composition of Silicate Minerals in the Chondrules and Matrix of the Buschhof Meteorite

2020 ◽  
Vol 58 (12) ◽  
pp. 1321-1330
Author(s):  
K. G. Sukhanova ◽  
S. G. Skublov ◽  
O. L. Galankina ◽  
E. V. Obolonskaya ◽  
E. L. Kotova
Keyword(s):  
Trace Element ◽  
Trace Element Composition ◽  
Element Composition ◽  
Silicate Minerals

scholarly journals Risk assessment of Ni, Cr, and Si release from alkaline minerals during enhanced weathering

2020 ◽  
Vol 5 (1) ◽  
pp. 166-175
Author(s):  
Fatima Haque ◽  
Yi Wai Chiang ◽  
Rafael M. Santos
Keyword(s):  
Risk Assessment ◽  
Environmental Protection Agency ◽  
Hazard Index ◽  
Carcinogenic Risk ◽  
Contamination Level ◽  
Potential Threat ◽  
Silicate Minerals ◽  
Guideline Value ◽  
Quality Guideline ◽  
Index Value

AbstractCalcium- and magnesium-rich alkaline silicate minerals, when applied to soil, can aid in carbon dioxide sequestration via enhanced weathering. The weathering of these silicate minerals is also associated with the release of heavy metals such as Ni and Cr, depending on the composition of the parent rock, and also labile Si. This paper critically analyses the risk associated with the release of Ni, Cr, and Si from alkaline silicate minerals as a result of enhanced weathering to evaluate its potential to be applied as a soil amendment. Based on the available data in the literature, this study evaluates the soil contamination level and quantifies the risk these elements pose to human health as well as the environment. To assess these potential threat levels, the geoaccumulation index was applied, along with the method recommended by the US Environmental Protection Agency for health risk assessment. The main findings of this study indicate the potential release of Ni, Cr, and Si to exceed the soil quality guideline value. The geochemical index suggests that the analyzed samples are in the class 0–3 and represents sites that lie between uncontaminated zones to highly contaminated zones. The hazard index value for Ni and Cr is greater than unity, which suggests that Ni and Cr release poses a non-carcinogenic risk. The probability of labile Si concentration in the soil to exceed the critical value is found to be 75%.

scholarly journals The mineralogic and isotopic fingerprint of equatorial carbonates: Kepulauan Seribu, Indonesia

2021 ◽  
Author(s):  
Dwi Amanda Utami ◽  
Lars Reuning ◽  
Maximillian Hallenberger ◽  
Sri Yudawati Cahyarini
Keyword(s):  
River Runoff ◽  
Patch Reef ◽  
High Water ◽  
Sem Analysis ◽  
Shallow Waters ◽  
Carbonate System ◽  
Riverine Water ◽  
High Turbidity ◽  
Java Sea ◽  
River Catchments

AbstractKepulauan Seribu is an isolated patch reef complex situated in the Java Sea (Indonesia) and is a typical example for a humid, equatorial carbonate system. We investigate the mineralogical and isotopic fingerprint of Panggang, one of the reef platforms of Kepulauan Seribu, to evaluate differences to other carbonate systems, using isotope in combination with XRD and SEM analysis. A characteristic property of shallow water (< 20 m) sediments from Kepulauan Seribu is their increased LMC content (~ 10%) derived from some genera of rotaliid foraminifers and bivalves. The relative abundance of these faunal elements in shallow waters might be related to at least temporary turbid conditions caused by sediment-laden river runoff. This influence is also evidenced by the presence of low amounts of siliciclastic minerals below the regional wave base. Kepulauan Seribu carbonates are characterized by very low δ13C and δ18O values. This is related to the isotopically depleted riverine input. The δ13CDIC in riverine water is reduced by the contribution of 12C from riverside mangroves. Deep atmospheric convection and intensive rains contribute 18O-depleted freshwater in the river catchments, finally reducing salinity in the Java Sea. The depleted δ13C signature in carbonates is further enhanced by the lack of green algae and inorganic carbonates and abundance of coral debris. Low δ18O values in carbonates are favored by the high water temperatures in the equatorial setting. Since equatorial carbonates in SE Asia, including the Java Sea, are typically influenced by high turbidity and/or river runoff, the observed distinctively low isotope values likely are characteristic for equatorial carbonate systems in the region.

Kimberlite melting relations revisited

1994 ◽  
Vol 121 (3-4) ◽  
pp. 261-262 ◽  
Author(s):  
S.E. Kesson ◽  
A.E. Ringwood ◽  
W.O. Hibberson
Keyword(s):  
Melting Relations

Enhanced diamond nucleation on pretreated silicon substrates

1997 ◽  
Vol 301 (1-2) ◽  
pp. 77-81 ◽  
Author(s):  
Ming-Rong Shen ◽  
Hao Wang ◽  
Zhao-Yuan Ning ◽  
Chao Ye ◽  
Zhao-Qiang Gan ◽  
...  
Keyword(s):  
Silicon Substrates ◽  
Diamond Nucleation
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