A closer look at cathodoluminescence of shocked quartz at the K/T boundary
A closer look at cathodoluminescence of shocked quartz at the K/T boundary (in Global catastrophes in Earth history; an interdisciplinary conference on impacts, volcanism, and mass mortality, Virgil L. Sharpton (editor) and Peter D. Ward (editor))
Special Paper - Geological Society of America (1990) 247: 343-347
- cathodoluminescence
- Cenozoic
- Colorado
- Cretaceous
- deformation
- framework silicates
- igneous rocks
- impacts
- K-T boundary
- lower Paleocene
- Mesozoic
- metamorphic rocks
- metamorphism
- New Mexico
- Paleocene
- Paleogene
- quartz
- Raton Basin
- shock metamorphism
- silica minerals
- silicates
- stratigraphic boundary
- Tertiary
- United States
- Upper Cretaceous
We examined 1,065 shock-deformed quartz grains from five Cretaceous/Tertiary (K/T) boundary sites in the Raton Basin, Colorado, and New Mexico, with cathodolum-inescence (CL) petrography. When grouped into general CL color categories, Raton Basin grains were 37.4 percent brown and 62.6 percent blue. Brown CL is thought to be associated with quartz from low-grade metamorphic rocks, so more than one third of the shocked grains were from this rock type. Almost all the blue CL quartz was medium to dark blue, broadly corresponding to quartz derived from intrusive igneous and high-grade metamorphic rocks. These data support the conclusions of a study by Owen and Anders (1988) which found no significant volcanic contribution to the shocked quartz at the K/T boundary. The proportions of brown- and blue-luminescing quartz in the present study differ from those of the previous study probably because of different sample preparation procedures and operator judgment.
