RT Journal Article
T1 Mineralogía y génesis de gemas de corales silicificados de Sumatra
T1 Mineralogy and genesis of gemstone silicified corals from Sumatra
A1 Sánchez Muñoz, Luis
A1 Bustillo Revuelta, María Ángeles
A1 García Guinea, Javier
A1 Crespo Feo, Elena
A1 Tormo, Laura
AB Mineral characteristics of silicified corals from Barisan Mountains (Miocene) of the Western Sumatra(Indonesia) have been studied by optical microscopy, Raman spectroscopy (spectral curves and hyperspectralimages) and scanning electron microscopy with energy dispersive microanalyses. Three different partswere recognized in the silicified coral, as follows: (i) the external shell, the radial septae and inner circularwalls and the core central part build with opal with some disperse carbon-rich black grains, showing theG and D Raman bands from residual organic matter; (ii) the inner caverns stuffed with mega-quartz crystalsof high crystallinity; (iii) chalcedony fibres occurring among both former zones, including moganite mineralas identified by its 502 cm-1 Raman band. During the subsequent processes of burial and diagenesis thedelicate organic structure of corals is substituted and consolidated by silica coming from the alteration ofash-flow and interstratified volcanic rocks. In addition, the presence of AgS and Zn-Cu minerals into thecoral fissures suggest later hydrothermal processes probably associated with the regional volcanic activity
YR 2009
FD 2009
LK http://hdl.handle.net/10272/8107
UL http://hdl.handle.net/10272/8107
LA spa
DS Repositorio Institucional de la Universidad de Huelva
RD 30 may 2026