Detrital zircon age constraints on basement history on the margins of the northern Rockall Basin

Morton, Andrew; Frei, Dirk; Stoker, Martyn S.; Ellis, David J.

doi:10.1144/sp397.12

Cited by 5 publications

(5 citation statements)

References 31 publications

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“…The Pleistocene (Unit 1) sample from Site 349 has a bimodal population, with some grains having augitic-salitic compositions and others being more ferroan (Figure 9). On the basis of the SiO2-Al2O3 diagram [38], distinct differences in the relative abundance of subalkaline and alkaline clinopyroxenes can be seen within the data set (Figure 10). The clinopyroxenes in Unit 3a at Site 349 appear to show a stratigraphic trend, with alkaline grains becoming more abundant higher in the section (Figure 6), culminating with the sample at 119.55 m, which, as discussed above, also shows the greatest degree of fractionation (Figure 9).…”

Section: Kap Brewstermentioning

confidence: 99%

“…Some of the minor phases (aegirine, aenigmatite, perovskite and sodic amphibole with the optical properties of arfvedsonite) are particularly significant because they diagnose sediment supply from evolved alkaline igneous rocks such as syenites. Two of these minerals, aenigmatite and perovskite, are extremely scarce as detrital minerals and only rarely have they been previously recorded in sandstones [36][37][38][39]. They were identified on the basis of their optical properties, with their presence confirmed by electron microprobe analysis.…”

Section: Heavy Mineral Assemblagesmentioning

confidence: 99%

“…Garnet populations (Figure 11) contain two main components, a high-Mg, low-Ca group and a low-Mg, variable Ca group (Types A and B in the terminology of Morton et al [38]). Type C (high-Mg, high-Ca) garnets are minor and Type D (Fe 3+ -Ca) are scarce.…”

Section: Garnetmentioning

confidence: 99%

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Provenance Response to Rifting and Separation at the Jan Mayen Microcontinent Margin

Morton

Jolley

Szulc³

et al. 2022

Geosciences

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The Eocene-Miocene successions recovered at DSDP sites on the Jan Mayen Ridge (NE Atlantic) and on the adjacent East Greenland margin provide a sedimentary record of the rifting and separation of the Jan Mayen Microcontinent from East Greenland. A combination of palynology, conventional heavy mineral analysis, single-grain major and trace element geochemistry and radiometric dating of amphibole and zircon has revealed a major change in sediment provenance took place at the Early/Late Oligocene boundary corresponding to a prominent seismic reflector termed JA. During the Eocene and Early Oligocene, lateral variations in provenance character indicate multiple, small-scale transport systems. Site 349 and Kap Brewster were predominantly supplied from magmatic sources (Kap Brewster having a stronger subalkaline signature compared with Site 349), whereas Site 346 received almost exclusively metasedimentary detritus. By contrast, Late Oligocene provenance characteristics are closely comparable at the two Jan Mayen sites, the most distinctive feature being the abundance of reworked Carboniferous, Jurassic, Cretaceous and Eocene palynomorphs. The Site 349 succession documents an evolution in the nature of the magmatic provenance component. Supply from evolved alkaline magmatic rocks, such as syenites, was important in the Middle Eocene and lower part of the Early Oligocene, but was superseded in the later Early Oligocene by mafic magmatic sources. In the latest Early Oligocene, the presence of evolved clinopyroxenes provides evidence for prolonged magmatic fractionation. Initial low degrees of partial melting led to generation of alkaline (syenitic) magmas. The extent of partial melting increased during the Early Oligocene, generating basaltic rocks with both subalkaline and alkaline compositions. Towards the end of the Early Oligocene, the amount of partial melting and magma supply rates decreased. In the Late Oligocene, there is no evidence for contemporaneous igneous activity, with scarce magmatic indicator minerals. The provenance change suggests that the hiatus at the Early/Late Oligocene boundary represents the initiation of the proto-Kolbeinsey Ridge and separation of the Jan Mayen Microcontinent from East Greenland.

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Section: Kap Brewstermentioning

confidence: 99%

Section: Heavy Mineral Assemblagesmentioning

confidence: 99%

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Provenance Response to Rifting and Separation at the Jan Mayen Microcontinent Margin

Morton

Jolley

Szulc³

et al. 2022

Geosciences

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“…The largest of these, the Rockall High, can be ruled out on the basis of zircon age data that indicate this region comprises crust formed ca. 1750-1800 Ma (Daly et al, 1995;Scanlon and Daly, 2001;Morton et al, 2009b;Morton et al, 2014). However, George Bligh High, located farther north, may be a more suitable candidate, since zircons in sediment shed from the George Bligh High include both Archean (2760( -2930 and Paleoproterozoic (1760-1930 ages (Morton et al, 2014).…”

Section: Northern Rockall Trough and Southern Faroe-shetland Basinmentioning

confidence: 99%

Reconstructing drainage pathways in the North Atlantic during the Triassic utilizing heavy minerals, mineral chemistry, and detrital zircon geochronology

Andrews

Morton²,

Decou

et al. 2021

Geosphere

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In this study, single-grain mineral geochemistry, detrital zircon geochronology, and conventional heavy-mineral analysis are used to elucidate sediment transport pathways that existed in the North Atlantic region during the Triassic. The presence of lateral and axial drainage systems is identified and their source regions are constrained. Axial systems are suggested to have likely delivered sediment sourced in East Greenland (Milne Land–Renland) as far south as the south Viking Graben (>800 km). Furthermore, the data highlight the existence of lateral systems issuing from Western Norway and the Shetland Platform as well as a major east-west–aligned drainage divide positioned adjacent to the Milne Land– Renland region. This divide separated the catchments that flowed north to the Boreal Ocean from those that flowed south into a series of endoreic basins and, ultimately, the Tethys Sea. A further potential drainage divide is identified to the west of Shetland. The data presented and the conclusions reached have major implications for reservoir prediction, as well as correlation, throughout the region. Furthermore, understanding the drainage networks that existed during the Triassic can help constrain paleogeographic reconstructions and provides an important framework for the construction of facies models in the region.

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“…A fresh approach to ditch-cuttings analysis is presented by Millet et al (2014) who describe how a robust volcanic stratigraphy can aid the construction of accurate basin models, especially where core data is limited or absent. Morton et al (2014) also address basement history through the use of detrital zircon age dating in the northern Rockall Basin and conclude that the Hebridean Platform is a westward extension of the Lewisian Complex, with age dates that can be directly correlated with events identified in the Outer Hebrides and NW Scotland.…”

Section: Technologiesmentioning

confidence: 99%

Hydrocarbon exploration and exploitation West of Shetlands

Austin¹,

Cannon²,

Ellis³

2014

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The oil and gas industry has been active in the West of Shetlands area for the last 40 years, but less than 200 wells have been drilled and only four fields have been developed. In the last ten years activity has picked up significantly with very active licensing rounds and increased drilling; however, the challenges of the complex geology and deep-water location, environmental constraints and commercial considerations have also increased at the same time. To fully develop the region successfully an attitude of compromise and collaboration between all the stakeholders must be nurtured, but with the scale of investment required this will remain a challenge for the future.

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Detrital zircon age constraints on basement history on the margins of the northern Rockall Basin

Cited by 5 publications

References 31 publications

Provenance Response to Rifting and Separation at the Jan Mayen Microcontinent Margin

Provenance Response to Rifting and Separation at the Jan Mayen Microcontinent Margin

Reconstructing drainage pathways in the North Atlantic during the Triassic utilizing heavy minerals, mineral chemistry, and detrital zircon geochronology

Hydrocarbon exploration and exploitation West of Shetlands

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