1 / 11

Garnet within Qbt

Garnet within Qbt. Rick Warren and Fraser Goff Retired, Los Alamos National Laboratory. Thin sections for SWNVF. Garnet habits in volcanics. SWNVF : GT in 60 of 313 thin sections JVF : GT in 10 of 76 thin sections. Grain shown is largest found, .091 mm (91,000 square microns).

hansel
Download Presentation

Garnet within Qbt

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Garnet within Qbt Rick Warren and Fraser Goff Retired, Los Alamos National Laboratory

  2. Thin sections for SWNVF

  3. Garnet habits in volcanics SWNVF: GT in 60 of 313 thin sections JVF: GT in 10 of 76 thin sections Grain shown is largest found, .091 mm (91,000 square microns)

  4. Garnet areas in thin section SWNVF only 131 grains

  5. Stratigraphic units and lithologies • All stratigraphic assemblages for SWNVF • From base to top of Qbt for JVF • Fractions of each lithology for SWNVF: • 62% are nonwelded tuff • 15% are welded tuff • 12% are alluvia • 7% are vitrophyric tuff • 3% are rhyolite lava

  6. Garnet in Qbt(10 of 67 thin sections)

  7. Garnet in sandstone lithics

  8. Garnet necklaces in argillite lithics

  9. BSE image of argillite lithics

  10. Garnet compositions

  11. Origin of garnet in volcanics • Necklaces require pneumatolytic origin • Carbonates completely absent • Argillites can provide Ca, Fe for andradite • Andradite also forms in other host lithics • Almandines likely detrital • Prevalence in SWNVF suggests that pneumatolytic andradite/grossular may commonly form in rhyolite vents

More Related