Mode of emplacement of the Slaufrudalur Pluton, Southeast Iceland inferred from three-dimensional GPS mapping and model building

• Published in: Tectonophysics Vol. 480; no. 1; pp. 232 - 240
• Main Authors: Burchardt, Steffi, Tanner, David C., Krumbholz, Michael
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05-01-2010
• Subjects: Berggrundsgeologi och petrologi; Cauldron subsidence; Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics; Earth sciences; Endogen geovetenskap; Endogenous earth sciences; Geographic information systems; Geovetenskap; Geovetenskap med inriktning mot mineralogi, petrologi och tektonik; Global Positioning System; GPS mapping; Granite emplacement; Layering; Magmatic stoping; Mapping; NATURAL SCIENCES; NATURVETENSKAP; Pluton shape; Roofs; Satellite navigation systems; Solid earth geology and petrology; Strikes; Three-dimensional modelling; Walls; ANE, Atlantic, Iceland; Pluton shape; GPS mapping; Magmatic stoping; Granite emplacement; Cauldron subsidence; Three-dimensional modelling
• ISSN: 0040-1951; 1879-3266; 1879-3266
• DOI: 10.1016/j.tecto.2009.10.010

The Slaufrudalur Pluton is a granitic pluton in the Tertiary lava pile of Southeast Iceland. Excellent exposures of its roof and walls made it possible to map the shape of the pluton with high-resolution GPS. Based on the GPS mapping and field observations, we reconstructed the three-dimensional shape of the Slaufrudalur Pluton with the aim to test which implications on the mechanisms of emplacement can be derived from this approach. The reconstructed pluton shape is characterised by steep walls and a flat roof at map-scale. This shape and the internal compositional layering indicate that the pluton was probably emplaced by cauldron subsidence along subvertical faults that are parallel with the strike of the regional fissure swarms. At the roof contact, the pluton exploited the original layering of the flood basalts. At outcrop-scale, however, the roof was modified by magmatic stoping, which resulted in a step-like pattern on a scale that cannot be resolved in the three-dimensional model. Hence, the reconstruction of the three-dimensional shape of the Slaufrudalur Pluton, combined with structural field studies, provided valuable information about the mechanism of its emplacement on pluton-scale. For a comprehensive understanding of all mechanisms involved in the emplacement of the Slaufrudalur Pluton, detailed structural field studies remain essential.