Abstract
The emplacement of lava flows into poorly consolidated sediments during volcanism can lead to a wide range of lava-sediment interaction processes. Understanding these processes and their products is critical for appraising reservoir quality and connectivity in both intra- and sub-volcanic prospectivity settings. This study investigates the nature of lava-sediment interactions during the onset of magmatism in sedimentary basins with the aid of field outcrops in the Paran ' a-Etendeka Igneous Province (Brazil), Mull Lava Field (UK), and Midland Valley Basin (UK). Both subaerial and invasive lava flows were identified with associated features ranging from peperites, loading structures, pillow-like peperites, rootless cones, and lavas with sharp contacts. Density contrasts between liquid magma and unconsolidated sediments make lava invasion a predictable phenomena in such environments, however, variations in sediment properties such as water saturation, porosity and cohesion may effectively restrict the process of invasion, the degree of loading and more dynamic processes leading to peperite and pillowlike peperite. Surface outcrop analogues form a key component to understand the potential impact of volcanism and magma-sediment interactions on non-volcanic reservoir rocks located proximal to the basalt-sediment transition. The intimate mixing of magma with sediment is generally restricted to a few meters from the lavasediment contact, with an associated minor impact on reservoir quality. However, the process of lava invasion may extend this impact further and may lead to partial or complete compartmentalization of associated reservoir units and may additionally impact correlation at the detailed reservoir level.
Original language | English |
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Article number | 103108 |
Number of pages | 15 |
Journal | Journal of South American Earth Sciences |
Volume | 108 |
Early online date | 7 Jan 2021 |
DOIs | |
Publication status | Published - Jun 2021 |
Bibliographical note
AcknowledgementsThis work was supported by Petrobras (CENPES R&D Projects PT-166.01.11923 and PT-166.01.13484), CNPq (402400/2016-0), and FAPERGS (18/2551-0001755-3). The Federal University of Rio Grande do Sul and University of Aberdeen are acknowledged for additional support. Dougal Jerram is partly funded by the Research Council of Norway Centre of Excellence funding scheme (project 223272). Natália Famelli specially acknowledges to M. Chmielewska, G. Bertolini; J. Machado, G. Marins, L. Bevilaqua, R. Rizzo for their support during fieldwork, discussions and/or software support. We thank the grinding plant of the 2° BFv, Arpasa, Ecobrix, Dois Irmãos, BT Construções, São Lucas quarries and the Ferrovia Centro-Atlântica (FCA – VLI Logística) for the permission to access the outcrop areas.
Keywords
- Volcanic-sedimentary interaction
- Peperite
- Invasive flow
- CONTINENTAL FLOOD BASALTS
- ETENDEKA IGNEOUS PROVINCE
- BREAK-UP
- MAGMATIC PROVINCE
- PETROLEUM SYSTEMS
- SOUTHERN BRAZIL
- VOLCANO
- PEPERITES
- BASIN
- STRATIGRAPHY