Morton, Andrew C; Keene, John B (1984): Geochemistry and minerals at DSDP Leg 81 Holes [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.806674, Supplement to: Morton, AC; Keene, JB (1984): Paleogene pyroclastic volcanism in the southwest Rockall Plateau. In: Roberts, DG; Schnittker, D; et al. (eds.), Initial Reports of the Deep Sea Drilling Project, Washington (U.S. Govt. Printing Office), 81, 633-643, https://doi.org/10.2973/dsdp.proc.81.119.1984
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Abstract:
Three phases of volcanism have been recognized in the lower Paleogene sequence of the southwest Rockall Plateau which are related to the onset of seafloor spreading in the NE Atlantic. The earliest, Phase 1, is marked by a sequence of tholeiitic basalts and hyaloclastites which form the dipping reflector sequence in Edoras Basin. Phase 2 is characterized by tuffs and lapilli tuffs of air-fall origin, ranging in composition from basic to intermediate. They were generated by highly explosive igneous activity due to magma-water interaction, and terminate at the level of a major transgression. Subsequently, volcanism reverted to tholeiitic basalt type, producing the thin tuffs and minor basalt flows of Phase 3.
Alteration of the volcanic glass and diagenesis of the tuffs and lapilli tuffs has been considerable in many cases, with a large number of diagenetic mineral phases observed, including smectite, celadonite, analcime, phillipsite, clinoptilolite, mordenite, and calcite. Although calcite is the latest observed diagenetic cement, it nevertheless occurred relatively early, in one case totally preserving basaltic glass from alteration.
Project(s):
Deep Sea Drilling Project (DSDP)
Coverage:
Median Latitude: 56.306511 * Median Longitude: -22.099821 * South-bound Latitude: 56.042700 * West-bound Longitude: -23.343500 * North-bound Latitude: 56.561700 * East-bound Longitude: -20.782200
Date/Time Start: 1981-07-31T00:00:00 * Date/Time End: 1981-08-31T00:00:00
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
3 datasets
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Datasets listed in this publication series
- Morton, AC; Keene, JB (1984): (Table 4) Geochemistry of volcanic glass at DSDP Holes 81-555 and 81-553A. https://doi.org/10.1594/PANGAEA.806673
- Morton, AC; Keene, JB (1984): (Table 2) Geochemistry of volcanic glass at DSDP Leg 81 holes Paleocene-Eocene pyroclastic deposits. https://doi.org/10.1594/PANGAEA.806671
- Morton, AC; Keene, JB (1984): (Table 3) Minerals of unaltered basaltic glass from DSDP Leg 81 holes pyroclastic deposits. https://doi.org/10.1594/PANGAEA.806672