Pathways of volcanic glass alteration in laboratory experiments through inorganic and microbially-mediated processes

Cuadros J., Afsin B., Jadubansa P., Ardakani M., Ascaso C., Wierzchos J.

Clay Minerals, cilt.48, sa.3, ss.423-445, 2013 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Derleme
  • Cilt numarası: 48 Sayı: 3
  • Basım Tarihi: 2013
  • Doi Numarası: 10.1180/claymin.2013.048.3.01
  • Dergi Adı: Clay Minerals
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.423-445
  • Anahtar Kelimeler: Biologically-mediated formation of clay, Cryo-SEM, Mineral-microbe interaction, Quartz formation, TEM-AEM, Volcanic glass alteration to clay
  • Ondokuz Mayıs Üniversitesi Adresli: Evet

Özet

Rhyolitic obsidian was reacted with natural waters to study the effect of water chemistry and biological activity on the composition and formation mechanisms of clay. Two sets of experiments (18 months, 6 years) used fresh, hypersaline water (Mg-Na-SO4-Cl- and NaCl-rich) and seawater. The 6-year experiments produced the transformation of obsidian into quartz, apparently by in situ re-crystallization (Cuadros et al., 2012). The most abundant neoformed clay was dioctahedral (typically montmorillonite), indicating chemical control by the glass (where Al > Mg). Altered glass morphology and chemistry in the 18-months experiments indicated in situ transformation to clay. Magnesium-rich (saponite) clay formed under water-chemistry control in the bulk and within biofilms with elevated Mg concentration (Cuadros et al., 2013). The contact between microbial structures and glass was very intimate. Glass transformation into quartz may be due to some characteristic of the obsidian and/or alteration conditions. Such combination needs not to be uncommon in nature and opens new possibilities of quartz origin. © 2013 The Mineralogical Society.