Toggle Main Menu Toggle Search

Open Access padlockePrints

The nature and significance of illite associated with quartz-hematite hydrothermal veins in the St. Austell pluton, Cornwall, England

Lookup NU author(s): Professor David ManningORCiD


Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


Quartz-hematite veins in the St. Austell pluton feature an assemblage of authigenic kaolin, illite, chlorite and hematite. Similar assemblages occur in altered granites adjacent to the veins. Complex textures in the veins and altered granites show that kaolin was an initial precipitate from hydrothermal fluids that was subsequently replaced by illite, hematite and chlorite. The sequence of mineral precipitation reflects a kinetic control on crystal growth, with early non-equilibrium precipitation of kaohn from fluids with compositions appropriate for the equilibrium formation of illite. Hematite formed under relatively oxidizing conditions that subsequently became more reducing to permit the late precipitation of chlorite. Illite associated with the quartz-hematite veins differs texturally, mineralogically and chemically from the coarsely crystalline hydrothermal muscovite (sericite or gilbertite) associated with quartz-tourmaline veins and greisen. Quartz-hematite veins are thus considered to record a distinct mineralization event that is not related to the early greisenization or the economic kaolinization.

Publication metadata

Author(s): Psyrillos A, Manning DAC, Burley S

Publication type: Article

Publication status: Published

Journal: Clay Minerals

Year: 2001

Volume: 36

Issue: 4

Pages: 585-597

Print publication date: 01/12/2001

ISSN (print): 0009-8558

ISSN (electronic): 1471-8030

Publisher: Mineralogical Society


DOI: 10.1180/0009855013640011


Altmetrics provided by Altmetric