Volatile and trace element composition of melt inclusions from the Lower Bandelier Tuff - implications for magma chamber processes and eruptive style
- New Mexico Inst. of Mining and Technology, Socorro (US)
The preeruptive volatile gradient that was present in the magma which produced the Lower Bandelier Tuff (LBT) is determined on the basis of an analysis of the H{sub 2}O, Cl, and F contents of melt inclusions (MIs) in LBT phenocrysts. The trace element contents of bulk pumice and MIs are measured in order to facilitate interpretation of the pristine nature of the MIs. The data show that there was a large gradient in the H2O content (hence density) of the magma between an H2O-saturated cap and the body of the chamber. The trace element analysis of the MIs and bulk rocks show that after the water gradient evolved, the chamber underwent about 40 percent eutectic fractional crystallization and was then intruded by a second rhyolitic magma at some time prior to eruption. 75 refs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 138905
- Journal Information:
- Journal of Geophysical Research, Vol. 97; Other Information: PBD: Oct 1992
- Country of Publication:
- United States
- Language:
- English
Similar Records
Evidence for dynamic withdrawal from a layered magma body: The Topopah Spring Tuff, southwestern Nevada
The Topopah Spring Tuff: Evidence for dynamic withdrawal from a layered magma body