ORCID Profile
0000-0001-9513-0147
Current Organisation
Nanyang Technological University
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Publisher: Mineralogical Society of America
Date: 05-2003
Publisher: Elsevier BV
Date: 03-2009
Publisher: Springer Science and Business Media LLC
Date: 11-2007
Publisher: Elsevier BV
Date: 04-2015
Publisher: Springer Science and Business Media LLC
Date: 1987
DOI: 10.1007/BF00628822
Publisher: MDPI AG
Date: 16-01-2020
DOI: 10.3390/MIN10010069
Abstract: Widespread alteration in the Early–Middle Triassic volcanic ash of the Xiejiacao section, south China, has resulted in significant occurrences of lithium-rich K-bentonite deposits with economic potential. Detailed mineralogical and geochemical investigations of Li-rich K-bentonite deposits from the Xiejiacao section of Guangan city, South China, are presented here. The X-ray diffraction (XRD) data and major element chemistry indicates that the Li-rich K-bentonite deposits contain quartz, clay minerals, feldspar, calcite and dolomite, and the clay minerals are dominated by illite and ordered (R3) illite/smectite (I/S). The concentrations of major and trace elements in Li-rich K-bentonite deposits altered from volcanic ashes are most likely derived from felsic magmas, associated with intense volcanic arc activity. The composition of the clay components suggests that the Li-rich K-bentonite deposits are probably altered from the smectite during diagenesis, whereas smectite is mainly formed by submarine alterations of volcanic materials and subsequently the I/S derived from the volcanogenic smectite illitization. Moreover, accurate determination of the structure in I/S reveals that the temperatures reached by the sedimentary series are around 180 °C with a burial depth of ~6000 m. The widely distributed lithium-rich clay deposits strongly indicate widespread eruptions of volcanic ashes in the Early–Middle Triassic, which released huge amounts of volcanic ash. Lithium fixed in the illite and I/S is considered to have leached from the volcanogenic products by a mixed fluid source (i.e., meteoric, porewater and hydrothermal fluids). These Li-rich clay minerals in the marine basin contain economically extractable levels of metal and are a promising new target for lithium exploration.
Publisher: Elsevier BV
Date: 03-2005
Publisher: Springer Science and Business Media LLC
Date: 08-2003
Publisher: Elsevier BV
Date: 12-2013
Publisher: American Chemical Society (ACS)
Date: 26-05-2009
DOI: 10.1021/CM9003917
Publisher: Mineralogical Society
Date: 10-1998
Abstract: The thermal dehydration of naturally occurring Ca-montmorillonite has been studied by in situ X-ray diffraction at temperatures between 60–120°C. The time-temperature-dependence of the position of the basal (001) reflection reveals that interlayer water loss on isothermal dehydration occurs in two stages. After an initial rapid decrease in interlayer spacing (on shock heating to an isothermal soak temperature) the reaction proceeds towards equilibrium more slowly. Furthermore, the width of the (001) reflection changes with time, reflecting transformation-dependent changes in homogeneity perpendicular to (001) with a maximum in peak width at the point where the rate of the reaction appears to change. This suggests that, as the interlayer spacing collapses, a local change is induced in the structure, affecting the means of movement of the water from the interlayer.
Publisher: Walter de Gruyter GmbH
Date: 08-2005
DOI: 10.1524/ZKRI.220.8.735.67077
Abstract: The sequence of ferroelectric phase transitions ( Pm 3̅ m — P 4 mm — Amm 2) in BaTiO 3 has been studied as a function of temperature (298 K–130 K) at a fixed pressure (3.2 GPa). The same sequence of transitions is observed as for ambient pressures, but the transition temperatures are reduced. The spontaneous strains of the non-cubic phases are determined. Whilst the structure of the tetragonal phase at high pressure is qualitatively similar to the ambient structure, both the spontaneous strain and the Ti displacement are smaller in the high pressure structure than the ambient structure.
Publisher: American Geophysical Union (AGU)
Date: 11-2015
DOI: 10.1002/2014PA002759
Publisher: IOP Publishing
Date: 06-2017
Publisher: Schweizerbart
Date: 25-07-2005
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Simon Redfern.