Illite crystallinity and the b-spacing values of white micas and their implications for gold mineralisation in the Lachlan Orogen

Autor:	Timothy J Rawling, A. L. Dugdale, W. D. Melling, M. J. McKenzie, C. J. L. Wilson, A. D. Farrar, Stafford McKnight
Rok vydání:	2009
Předmět:	geography geography.geographical_feature_category Muscovite Metamorphic rock Geochemistry Metamorphism Fault (geology) engineering.material Turbidite Illite crystallinity Earth and Planetary Sciences (miscellaneous) engineering Pelite General Earth and Planetary Sciences Cleavage (geology) Geology
Zdroj:	Australian Journal of Earth Sciences. 56:1143-1164
ISSN:	1440-0952 0812-0099
DOI:	10.1080/08120090903246238
Popis:	Gold mineralisation in the Lachlan Orogen of western Victoria, is generally hosted in turbidites with very low-grade metamorphic assemblages. Metamorphic data from these turbidites are relatively rare because of the fine-grained nature of the pelitic component and lack of suitable assemblages for thermobarometric estimates. In this study, ‘illite crystallinity’ (Kubler Index) and b-lattice spacing measurements were carried out on white micas in metapelites, collected from near the inferred western margin of the Selwyn Block, as well as three exploration targets, in an attempt to relate thermal and barometric conditions to mineralisation. Higher-grade (epizone) metamorphic conditions are recorded in sequences west of the Whitelaw Fault and lower-grade (anchizone) metamorphic conditions to the east of the fault. The change from epizonal to anchizonal grade is abrupt, resolved to a distance of a few hundred metres. The b-spacing values change adjacent to the Muckleford Fault. This is due to rocks to the east...
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::51e02f6b418632ab4bc5c8f087aa3027 https://doi.org/10.1080/08120090903246238 Zobrazit plný text záznamu