UAV Photogrammetry of Inflated Komatiite Flow Lobes in an Archean Bimodal Volcanic Terrane, Yilgarn Craton, Western Australia
Abstract
Previous studies of large komatiite fields in Archean greenstone belts in Western Australia and elsewhere have led to the suggestion that komatiite lavas were emplaced by similar mechanisms to modern pahoehoe flows, notwithstanding the very low viscosities and sea-floor eruption setting. Of komatiites. We use UAV photogrammetry to identify and map inflation features characteristic of modern pahoehoe flows in Archean komatiites at the Gordon Sirdar Lake locality near Kalgoorlie. Komatiite lavas, forming part of the 2705 Ma old plume-related bimodal volcanic sequence of the Eastern Goldfields Superterrane, Yilgarn Craton, were emplaced within a sequence of dacitic lava flows and semi-consolidated tuffs. The sequence was tilted to the vertical on the flanks of a regional isoclinal fold, and is exposed as partially weathered outcrop in the bed of a playa lake. Komatiite lava lobes form characteristic lenticular cross sections ranging from 1-6 m thick and up to 20m long, in some cases with lower margins draped over pre-existing dacite flow tops, and in others showing invasive textures implying eruption onto or into wet sediment. Inflation features include tumuli, inflation clefts, breakouts, and terraced margins. Spinifex textures are preserved locally at flow tops and rarely at bases. High temperature (>1400 C) and low viscosities (<50 Pa s) of komatiites evidently do not preclude inflation as an emplacement mechanism of individual flows. Flow-top morphology has been used to identify inflation of basaltic lava flows in Martian environments. We suggest these criteria may be extended to the possible recognition of Martian komatiites.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.P33D2184B
- Keywords:
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- 4558 Sediment transport;
- OCEANOGRAPHY: PHYSICALDE: 6281 Titan;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTSDE: 6295 Venus;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTSDE: 5405 Atmospheres;
- PLANETARY SCIENCES: SOLID SURFACE PLANETS