← Search
Sample DP2
NavDat sample number 4999 · GABBRO
Sample
| Sample ID | DP2 |
|---|
| Rock name | GABBRO |
|---|
| Rock type | PLUTONIC |
|---|
| Composition | MAFIC |
|---|
| Material | IGNEOUS |
|---|
| Collected by | R.T. Forest and W.R. Benoit, Phillips Petroleum Co., Reno, NV |
|---|
| Comment | X-ray fluorescence analyses hornblende K2O = 0.40%, plagioclase K2O = 1.46% confirm the flame photometer results. The unusually high atmospheric argon content of both minerals is typical of rocks that have undergone hydrothermal alteration. Discordance indicates resetting of plagioclase and perhaps both minerals by post crystallization thermal activity. The 26-m.y.-hornblende age is typical of ages of andesites in the region, and the high Sr content 1550 ppm of the plagioclase is typical of those andesites. |
|---|
Location
| Latitude | 39.7383 |
|---|
| Longitude | -118.967 |
|---|
| Location | Churchill County |
|---|
| State / province | Nevada |
|---|
Age
| Age (Ma) | Error | Min | Max | Geologic age | Dated by |
|---|
| 26.2 |
|
25 |
27.4 |
|
M.L. Silberman, U.S. Geological Survey |
Analyses
No chemical analyses are stored for this sample.
References
- Morton, Janet L. and Silberman, Miles L. of the U.S. Geological Survey, Menlo Park; Bonham, H.F. and Garside, Larry J. of the Nevada Bureau of Mines and Geology, Reno; and Noble, Donald C. of the Michigan Technological University, Houghton (1977) K-AR AGES OF VOLCANIC ROCKS, PLUTONIC ROCKS, AND ORE DEPOSITS IN NEVADA AND EASTERN CALIFORNIA - DETERMINATIONS RUN UNDER THE USGS-NBMG COOPERATIVE PROGRAM.
