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Gold mineralisation in a syntectonic granite dike, Sams Creek, northwest Nelson, New Zealand
| Content Provider | Scilit |
|---|---|
| Author | Windle, S. J. Craw, D. |
| Copyright Year | 1991 |
| Description | Riebeckite granite at Sams Creek, northwest Nelson, was intruded as an 8 km long dike into slate and quartzite metasediments (Wangapeka Formation) before or during deformation under greenschist facies conditions. Lamprophyre intrusion accompanied granite emplacement. Deformation after intrusion resulted in folding of metasediments on a northerly trend, and buckling of the east‐striking granite and lamprophyre dikes. The intrusives were dismembered and now occur as a sinuous train of small (c. 100 m) subequant bodies. Metamorphogenic fluid from the metasediments interacted with the granite at about 300 ± 60°C and 100–200 MPa fluid pressure. The fluid was predominantly water with minor $CO_{2}$ (saturated), and contained up to 7.5 wt% dissolved salts. The fluid/rock ratio was low, and whereas little chemical or mineralogical change occurred in the granite, its distinctive $Fe^{3+}$‐rich composition localised Au‐As mineralisation. Pyritisation of magnetite caused fluid pH to rise, and Au to precipitate. Further water/rock interaction resulted in a pH decrease, sericitisation of feldspars, and dissolution of Au. |
| Related Links | https://www.tandfonline.com/doi/pdf/10.1080/00288306.1991.9514481?needAccess=true |
| Ending Page | 440 |
| Page Count | 12 |
| Starting Page | 429 |
| ISSN | 00288306 |
| e-ISSN | 11758791 |
| DOI | 10.1080/00288306.1991.9514481 |
| Journal | New Zealand Journal of Geology and Geophysics |
| Issue Number | 4 |
| Volume Number | 34 |
| Language | English |
| Publisher | Informa UK Limited |
| Publisher Date | 1991-12-01 |
| Access Restriction | Open |
| Subject Keyword | Journal: New Zealand Journal of Geology and Geophysics Geology Gold Riebeckite Granite Fluid Inclusions Northwest Nelson Geochemistry |
| Content Type | Text |
| Resource Type | Article |
| Subject | Geology Geophysics |
