Pyroclastic-rock
A rock classification type
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About Pyroclastic-rock
Rocks composed of volcanic fragments derived from explosive volcanic activity. Pyroclastic rocks contain more than 75% by volume of pyroclastic fragments, the remaining materials being generally of epiclastic, organic, chemical sedimentary or authigenic origin. Tephra is the unconsolidated equivalent.
Unique Identifiers
Mindat ID:
48582
Long-form identifier:
mindat:1:1:48582:7
Classification of Pyroclastic-rock
64mm)' b='Lapilli (64-2mm)' c='Ash (<2mm)' actions='fill #cccccc 100,0,0 to 75,25,0 to 75,0,25;fill #cccccc 75,25,0 to 75,0,25 to 25,0,75 to 25,75,0;
fill #cccccc 0,100,0 to 25,75,0 to 0,75,25;
fill #cccccc 0,0,100 to 25,0,75 to 0,25,75;
fill #cccccc 25,0,75 to 0,25,75 to 0,75,25 to 25,75,0;
text dark 12 70,18 pyroclastic breccia;text dark 12 70,21.5 agglomerate;line dark 69,19 to 87.5,6.25,6.25;text dark 13 42,28,28 tuff breccia;text dark 13 12,44,44 lapilli tuff;text dark 12 2,70 lapillistone;text dark 12 85,70 tuff/ash tuff;line dark 6.25,87.5,6.25 to 9,71;line dark 6.25,6.25,87.5 to 92,71;'>
Classification of polymodal pyroclastic rocks (after Fisher, 1966)
Sub-divisions of Pyroclastic-rock
Age distribution
Recorded ages:
Cenozoic : 10.1 ± 1.0 Ma to 0.084 ± 0.0007 Ma - based on 7 recorded ages.
Sample ages:
| Sample ID | Recorded age | Geologic Time | Dating method |
|---|---|---|---|
| 1 | 0.181 ± 0.0012 to 0.084 ± 0.0007 Ma | Pleistocene | Ar/Ar |
| 2 | 0.94 ± 0.14 Ma | Pleistocene | |
| 3 | 2.54 Ma | Pleistocene | K-Ar |
| 4 | 4.8 ± 0.2 Ma | Pliocene | K-Ar |
| 5 | 5.332 to 2.588 Ma | Cenozoic | geological evidence |
| 6 | 10 to 7 Ma | Miocene | |
| 7 | 10.1 ± 1.0 Ma | Miocene | K-Ar |
Sample references:
| ID | Locality | Reference | Notes |
|---|---|---|---|
| 1 | Pantelleria Island, Trapani Province, Sicily, Italy | age for welded and rheomorphic ignimbrites that preceded the 2 caldera collapses | |
| 2 | Mount Murphy, Marie Byrd Land, West Antarctica, Antarctica | ||
| 3 | Chilallo Volcano, Arsi Zone, Oromia Region, Ethiopia | ||
| 4 | Kanatim Volcano, Turkana County, Kenya | from basal welded tuff | |
| 5 | Mau Volcanic Area, Narok County, Kenya | ||
| 6 | Jones Mountains, West Antarctica, Antarctica | ||
| 7 | Jebel Siroua, Askaouen Caïdat, Taliouine Cercle, Taroudant Province, Souss-Massa Region, Morocco |
Synonyms of Pyroclastic-rock
Internet Links for Pyroclastic-rock
mindat.org URL:
https://www.mindat.org/min-48582.html
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Search Engines:
References for Pyroclastic-rock
Reference List:
Aiguilhe, Le Puy-en-Velay, Haute-Loire, Auvergne-Rhône-Alpes, France