Hydrothermal alteration in the Mount Hood area, Oregon.
Bargar, Keith E; Keith, Terry E C; Beeson, Melvin H (1993) Hydrothermal alteration in the Mount Hood area, Oregon. U. S. Geological Survey Bulletin. 1993.
| Authors | Bargar, Keith E; Keith, Terry E C; Beeson, Melvin H |
|---|---|
| Year | 1993 |
| Title | Hydrothermal alteration in the Mount Hood area, Oregon. |
| Source | U. S. Geological Survey Bulletin. 1993. |
| Publisher | U. S. Geological Survey. Reston, VA, United States. Pages: 70. 1993. |
| Document type | Serial; Report |
| ISSN | 8755-531X |
| GeoRef | 1993-011329 |
| Keywords | Cascade-Range; Cenozoic-; Clackamas-County-Oregon; Columbia-River-Basalt-Group; cuttings-; facies-; fluid-inclusions; geochemistry-; geologic-thermometry; geothermal-energy; greenschist-facies; Hood-River; hydrothermal-alteration; inclusions-; lava-; major-elements; metamorphic-rocks; metamorphism-; metasomatism-; metavolcanic-rocks; Miocene-; Mount-Hood; Neogene-; northwestern-Oregon; Oregon-; outcrops-; P-T-conditions; paleosalinity-; Quaternary-; Rhododendron-Formation; SEM-data; stratovolcanoes-; Tertiary-; trace-elements; United-States; upper-Tertiary; USGS-; volcaniclastics-; volcanoes-; well-logging; zeolite-facies |
Abstract
Hydrothermal alteration of outcrop and drill hole samples in the Mount Hood area indicates that late Tertiary volcanic rocks experienced temperatures corresponding to those of very low grade zeolite-facies to greenschist-facies metamorphism ( approximately 50 degrees to 400 degrees C). Greenschist-facies metamorphism appears to have been confined to narrow halos surrounding quartz diorite to quartz monzonite intrusions that formed about 8 to 11 Ma and approximately 5 Ma. Widespread, lower temperature, zeolite-facies minerals frequently are superimposed on the higher temperature greenschist to subgreenschist mineral assemblages. Quaternary lava flows and volcaniclastic deposits contain only sparse low-temperature hydrothermal and fumarolic minerals.
15 samples from this reference
| Sample | Rock name | Major | Trace | Isotope |
|---|---|---|---|---|
| 81 MH-14 | Andesite | yes | yes | |
| 81 MH-21 | Andesite | yes | yes | |
| 79 ZZL-1089 | Basalt | yes | yes | |
| 79 CCT-1094 | Andesite | yes | yes | |
| 79 LP-1108 | Dacite | yes | yes | |
| 79 KL-1120A | Andesite | yes | yes | |
| 79 LL-1126C | Andesite | yes | yes | |
| 80 CF-0022A | Andesite | yes | yes | |
| 80 ZM-1013 | Andesite | yes | yes | |
| 80 ZM-1023A | Andesite | yes | yes | |
| 80 ZM-1030 | Andesite | yes | yes | |
| 82 MH-1 | Andesite | yes | yes | |
| 79 LH-1058A | Not-given | yes | yes | |
| 80 LH-1058 | Granite | yes | yes | |
| 80 LH-1035 | Granite | yes | yes |