Helen's Reef: a microgabbroic intrusion in the Rockall intrusive centre, Rockall Bank

Roberts, D.G.; Flemming, N. C.; Harrison, R. K.; Binns, P. E.; Snelling, N. J.

doi:10.1016/0025-3227(74)90021-8

Cited by 25 publications

(12 citation statements)

References 14 publications

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“…Cretaceous (100 ± 20 m.y.) apatite ages are consistent with known high level microgabbroic intrusives on Helen's Reef (Roberts et al, 1974). Such apatite ages could also be derived from basement rocks of very ancient terrains, especially around rifted continental margins where low level heating or uplift has affected the fission track ages of apatites (Gleadow, 1978).…”

supporting

confidence: 73%

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Fission Track Dating of Apatite and Sphene from Paleogene Sediments of Deep Sea Drilling Project Leg 81, Site 555

Duddy¹,

Gleadow²,

Keene³

1984

Initial Reports of the Deep Sea Drilling Project

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Fission track ages of individual crystals of detrital apatite and sphene separated from early Eocene and Paleocene sandstones at Site 555 indicate the contribution of detritus from source rocks of at least three distinct age groups. A major group of Tertiary (56 ± 3 m.y.) apatite ages is compatible with either contemporaneous or near contemporaneous volcanism or rapid unroofing of high level intrusives like those identified previously on Rockall Island (Jones et al., 1972) and Greenland (Gleadow and Brooks, 1979). Cretaceous (100 ± 20 m.y.) apatite ages are consistent with known high level microgabbroic intrusives on Helen's Reef (Roberts et al., 1974). Such apatite ages could also be derived from basement rocks of very ancient terrains, especially around rifted continental margins where low level heating or uplift has affected the fission track ages of apatites (Gleadow, 1978).Minor contributions were also identified from a terrain with apatite ages around 150 to 200 m.y. Similar ages are known from granitic and metamorphic rocks in Greenland (Gleadow, 1978;Gleadow and Brooks, 1979). From experience elsewhere in the North Atlantic Craton (Gleadow, 1978), such apatite ages are also likely in the basement rocks of Rockall, but direct fission track results are lacking.With the identification of at least two nonmetamorphic sources, these data enable a refinement of the source of apatite suggested by heavy mineral studies (Morton, this volume).Two distinct groups of sphene ages of around 60 and 1,380 m.y. are also consistent with sources either on the Rockall Bank or in Greenland (Gleadow, 1978).Apatites from around 900 m depth have a combined age very close to the age of deposition, and they have track length distributions indicating that present temperatures in the hole are at, or close to, the maximum experienced since deposition.

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confidence: 73%

“…Similarly, a source with Cretaceous apatite ages possibly comprises the high level microgabbroic intrusives at Helen's Reef on the Rockall Plateau (Roberts et al, 1974).…”

Section: Provenance Of the Eocene Sedimentsmentioning

confidence: 99%

Fission Track Dating of Apatite and Sphene from Paleogene Sediments of Deep Sea Drilling Project Leg 81, Site 555

Duddy¹,

Gleadow²,

Keene³

1984

Initial Reports of the Deep Sea Drilling Project

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“…2) is not well known and their general distribution within the North Rockall Trough is still the subject of some debate (e.g. Roberts et al 1983;Wood et al 1987;Abraham & Ritchie 1991;Boldreel & Andersen 1993). Arguably, the lavas are patchily developed, leaving some areas where they are completely absent (Fig.…”

Section: North Rockall Trough -Hebrides Lavasmentioning

confidence: 99%

Early Paleogene offshore igneous activity to the northwest of the UK and its relationship to the North Atlantic Igneous Province

Ritchie

Hitchen

1996

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Offshore occurrences of Early Tertiary igneous rocks to the northwest of Britain are allocated to seven major categories using criteria such as geographical location, structure, age and genetic relationship. The categories are: (1) Faeroe Plateau Lava Group; (2) North Rockall Trough-Hebrides Lava Group; (3) central igneous complexes; (4) volcaniclastic rocks; (5) Faeroe-Shetland Intrusive Complex; (6) the Minch; and (7) Wyville-Thomson Ridge. An igneous chronology is presented based on radiometric age dating (mainly K-Ar whole rock), biostratigraphical data and seismic relationships.Most landward central complexes (i.e. Skye, Rhum, Ardnamurchan, Mull, Arran) pre-date those which are more oceanward (i.e. Erlend, Darwin, St Kilda, Rockall). Exceptions to this trend (i.e. Rosemary Bank, Anton Dohrn, Hebrides Terrace) are probably genetically linked to crustal thinning in the Rockall Trough. The age of the Faeroe Plateau Lava Group, and especially the contiguous Rockall Trough-Hebrides Lava Group, are not particularly well constrained.The main intrusive phase on, and to the southeast of, the Faeroe Islands (i.e. Faeroe-Shetland Intrusive Complex) was a relatively late stage magmatic event, coeval with the opening of the North Atlantic between Greenland and NW Europe.

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“…Radiometric dating of a dyke rock initially gave a figure of 70.4 Ma (Durant et al 1976). Although the sample gave a minimum age due to argon loss the figure compared closely with many from the Rockall area (Roberts et al 1974). Subsequently, an age of 57 Ma by Mitchell et al (1976) using dredged basalt samples was published.…”

Section: Igneous Intrusionsmentioning

confidence: 58%

Aspects of the geology of the Malin Sea area

Dobson

Whittington

1992

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A complex of sediment-filled graben and half-graben, separated by acoustic basement, occupy much of the northwest shelf of the British Isles. Some were established in the Late Carboniferous, but most were formed during a post-Hercynian tensional phase that adopted Caledonoid-trending structures in the basement. A major graben complex occurs in the Malin Sea area; flanked by the Coll-Tiree-Skerryvore-Stanton Banks basement ridge to the north and by the lslay-Donegal Platform to the south. Rock samples obtained by divers from the two basement ridges confirm their Precambrian character. Limited commercial multichannel reflection seismic data together with BIRPS WIRE lines and structural information supplied by Texaco suggest that the graben complex consists of three major depocentres: the Inner Hebrides Trough, the Malin Basin and the South Donegal Basin. To the west lies the Main Donegal Basin. This basin, in concert with the South Donegal Basin, evolved during the Carboniferous as a result of dextral strike slip movement between the Stanton Banks in the north and the Islay-Donegal Platform to the south. Sea bed core and dredge material and well data recovered from the graben complex indicate that the basin sediments include Upper Carboniferous, Permo-Triassic, Lower Jurassic, Middle Jurassic, with thick Cretaceous and Lower Tertiary in the far west. Periods of uplift and erosion restricted sedimentation during the late Mesozoic, whilst uplift and erosion in the early Tertiary was accompanied by extensive igneous activity, with the development of two plutonic centres and twelve other smaller intrusive igneous bodies. Tertiary sediments arc inferred for the Blackstones Basin by analogy with similar sequences elsewhere in the Hcbridean area. A thick Quaternary section, dominated by glaciomarine sediments, contains three of the five glacial cycles that constitute the Pleistocene in this area.

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Helen's Reef: a microgabbroic intrusion in the Rockall intrusive centre, Rockall Bank

Cited by 25 publications

References 14 publications

Fission Track Dating of Apatite and Sphene from Paleogene Sediments of Deep Sea Drilling Project Leg 81, Site 555

Fission Track Dating of Apatite and Sphene from Paleogene Sediments of Deep Sea Drilling Project Leg 81, Site 555

Early Paleogene offshore igneous activity to the northwest of the UK and its relationship to the North Atlantic Igneous Province

Aspects of the geology of the Malin Sea area

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