The University of Southampton
University of Southampton Institutional Repository

Widespread inflation and drainage of a p?hoehoe flow field: the Nesjahraun, Þingvellir, Iceland

Record type: Article

This study describes the emplacement of the Nesjahraun, a basaltic lava flow that entered the lake Þingvallavatn, SW Iceland. High-resolution remotely sensed data were combined with fieldwork to map the flow field. Onshore, the Nesjahraun exhibits a variety of textures related to the widespread inflation and collapse of a p?hoehoe flow field. Its emplacement is interpreted as follows: Initially, the eruption produced sheet p?hoehoe. In the central part of the flow field, the lava has a platy-ridged surface, which is similar to some other lava flows in Iceland and on Mars. Here, the texture is interpreted to have formed by unsteady inflation of the brittle crust of stationary sheet p?hoehoe, causing it to break into separate plates. The ridges of broken p?hoehoe slabs formed as the plates of crust moved vertically past each other in a process similar to the formation of shatter rings. Upstream, fresh lava overflowed repeatedly from channels and tubes, covering the surface with shelly p?hoehoe. Formation of a 250-m-wide open channel through the flow field allowed the inflated central part of the flow to drain rapidly. This phase produced ‘a‘? lava, which eroded the channel walls, carrying broken p?hoehoe slabs, lava balls and detaching large (>200 m long) rafts of compound shelly p?hoehoe lava. Much of this channelized lava flowed into the lake, leaving a network of drained channels and tubes in the upstream part of the flow. As in other locations, the platy-ridged texture is associated with a low underlying slope and high eruption rate. Here, its formation was possibly enhanced by lateral confinement, hindered entry into the lake and an elevated vent location. We suggest that formation of this type of platy-ridged lava, where the plates are smooth and the ridges are slabs of broken p?hoehoe, can occur without significant horizontal transport, as the surface crust is broken into plates in situ. This reconstruction of the emplacement of the Nesjahraun also demonstrates that high-resolution aerial survey data are extremely useful in the mapping and measurement of lithofacies distributions in large flow fields, but that fieldwork is still necessary to obtain the detailed textural information necessary to interpret them.

Full text not available from this repository.

Citation

Stevenson, John Alexander, Mitchell, Neil Charles, Cassidy, Michael and Pinkerton, Harry (2012) Widespread inflation and drainage of a p?hoehoe flow field: the Nesjahraun, Þingvellir, Iceland Bulletin of Volcanology, 74, (1), pp. 15-31. (doi:10.1007/s00445-011-0482-z).

More information

Published date: 2012
Keywords: LiDAR, Lava, Iceland, Platy-ridged lava, Inflation, Shelly p?hoehoe
Organisations: Geochemistry

Identifiers

Local EPrints ID: 338935
URI: http://eprints.soton.ac.uk/id/eprint/338935
ISSN: 0258-8900
PURE UUID: f8eba96c-6b85-467f-98a0-d86dbe2f9ce6

Catalogue record

Date deposited: 17 May 2012 14:38
Last modified: 18 Jul 2017 05:56

Export record

Altmetrics

Contributors

Author: John Alexander Stevenson
Author: Neil Charles Mitchell
Author: Michael Cassidy
Author: Harry Pinkerton

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×