| Abstract: | This group of some 15 Late Quaternary explosion craters are typical maars, with rims of bedded pyroclastics. In all but the largest crater, the deposits consist entirely of clasts of country rock (granodiorite and Eocene volcanics). The maars were formed by phreatomagmatic explosions, possibly caused by groundwater originating from a major river. The deposits of the largest maar contain up to 20% juvenile fragments of two types. Tephrite clasts have phenocrysts of phlogopite, clinopyroxene, olivine and anorthoclase; the presence of hauyne as a groundmass phase is notable. Cumulate blocks of phlogopite-clinopyroxene rock also occur. The maar field is part of a distinct province of Quaternary alkaline volcanism, related to a major crustal fracture - the N-S-trending Nayband fault.-R.J.S. |
| Genre: | Article |
| ProdID: | 70011156 |
| Citation Author: | Milton, D. J. |
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| Citation End Page: | 208 |
| Citation Issue: | 3 |
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| Citation Language: | English |
| Citation Larger Work Title: | Bulletin Volcanologique |
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| Citation Number Of Pages: | 8 |
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| Citation Search Results Text: | Qal‘eh Hasan Ali maars, central Iran.; 1976; Article; Journal; Bulletin Volcanologique; Milton, D. J. |
| Citation Start Page: | 201 |
| Citation Volume: | 40 |
| Citation Year: | 1976 |
| Type: | citation/reference |
| Text: | Qal‘eh Hasan Ali maars, central Iran.; 1976; Article; Journal; Bulletin Volcanologique; Milton, D. J. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Thu, 1 Jan 1976 00:00 -0600 |
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