Abstract
Coherent-Margined Volcaniclastic Dikes (CMVDs) are described for the first time from Askja (Dyngjufjöll), Iceland. These dikes display continuous, coherent glassy margins 5. cm thick and have a variety of clastic interiors comprising vitric tephra, pillow and pillow-fragment bearing lapilli tuffs. CMVDs are interpreted to form when basaltic dikes interact with subglacial ice-cemented volcaniclastic sediments. Formation requires chilling of dike margins, drainage of the dike interior and flooding of the cavity by meltwater, followed by non-explosive mingling of magma, clastics and water. Evidence for ice-cementation includes minimal interaction with the host (< 3. mm peperite), local pillowed dike margins and the preservation of continuous glassy coherent margins along the edge of a drained dike cavity. CMVDs should be present at other volcanic centers with ice-cemented sediments, including the Martian cryosphere.
| Original language | English |
|---|---|
| Pages (from-to) | 30-38 |
| Number of pages | 9 |
| Journal | Journal of Volcanology and Geothermal Research |
| Volume | 217-218 |
| DOIs | |
| Publication status | Published - 1 Mar 2012 |
Bibliographical note
Funding Information: This research was funded through a NSF grant awarded to IPS, DMG and ARH. The purpose of this grant was the PhD research of AHG, which is still in progress. This publication is one of several anticipated to result from this work. All travel and analyses associated with this work were funded from this source. Funding Information: This work was enabled by a NSF grant to IPS. Thanks to the NORVOLK Institute and field assistant K. Reath. This manuscript benefited from constructive discussions with B. Edwards and reviews from Jim Head and an anonymous reviewer.Other keywords
- Askja
- Glaciovolcanic
- Ice-cemented
- Iceland
- Intrusions
- Peperite