Origin of Pillow Structure in Early Precambrian Lavas of Western Quebec

Wilson, M.

doi:10.1086/626640

Cited by 13 publications

(6 citation statements)

References 21 publications

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“…Variolitic textures commonly result from rapid freezing of basaltic liquids and are usually reported from the pillowed portions of submarine extrusions. However, variolitic textures have been reported from intrusive sills and even from pillows intrusive into soft marine sediments (Wilson, 1960;Garrison, 1972) and thus are unreliable indicators of underwater extrusion.…”

Section: Nature Of Emplacementmentioning

confidence: 99%

Petrology of Volcanic Rocks Recovered on DSDP Leg 19 from the North Pacific Ocean and the Bering Sea

Stewart¹,

Natland²

1973

Initial Reports of the Deep Sea Drilling Project

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Section: Nature Of Emplacementmentioning

confidence: 99%

Petrology of Volcanic Rocks Recovered on DSDP Leg 19 from the North Pacific Ocean and the Bering Sea

Stewart¹,

Natland²

1973

Initial Reports of the Deep Sea Drilling Project

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“…Pillow lavas are generally accepted as having formed in contact with water or water saturated materials (Wilson 1960;Snyder and Fraser 1963;Macdonald 1967) but are not in themselves reliable indicators of water depth. Totally subaqueous eruptions can give rise to both pillow lavas and breccias, and in shallow water to tuff and scoria (Cotton 1969; Moore and Fiske 1969;Jones 1970).…”

Section: F Llyn Y Gafr Formationmentioning

confidence: 99%

Ordovician palaeogeography of the southern and eastern flanks of the Harlech Dome, Merionethshire, North Wales

Ridgway

1976

Geological Journal

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The Arenig to Caradoc palaeogeographic evolution of the Harlech Dome region is interpreted from a study of the volcanic and sedimentary successions on the eastern and southern flanks of the Dome. Acid ignimbrite volcanism is shown to have been associated with periods of uplift and intermediate to basic volcanism with periods of subsidence. The evolution of the region can be compared to that of an island arc.Gaol.

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“…The virtual restriction of olivine to the lower variolitic zone can be attributed to gravitational settling also within a sill. Variolitic textures are usually found in pillow margins, but have been reported from sills (Wilson, 1960;Garrison, 1972). Pilotaxitic texture is a feature usually found in andesites and is uncommon in more mafic volcanics, although it has been reported from other DSDP basalts (Erlank and Reid, 1974;Thompson et al, 1974).…”

Section: Petrographymentioning

confidence: 99%

Petrology and Geochemistry of DSDP Leg 35 Basalts, Bellingshausen Sea

Vennum¹

1976

Initial Reports of the Deep Sea Drilling Project

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Basaltic rocks were recovered from two sites on the abyssal plain of the Bellingshausen Sea during Leg 35 of the Deep Sea Drilling Project. Disoriented basaltic cobbles, some of which have glassy rinds, hyaloclastite fragments, and numerous chips of black glass cored at Site 322 are interpreted to be the upper surface of a brecciated pillow flow. However, high penetration rates (12-13 m/hr) indicate the drilled interval may consist of interbedded lava flows and sediments, and true oceanic basement (layer 2) probably was not reached. Except for an abnormally high K2O content, the mineralogy and chemistry are typical of average mid-ocean ridge tholeiites. Many of the plagioclase microphenocrysts contain irregular to sharply bounded cores of almost pure potassium feldspar, a feature previously reported from Sites 165 (Leg 17) and 192 (Leg 19). This feature probably results from the filling of hollow centers of hopper crystals by potassic-rich solutions produced during alteration. Textural variation, mineralogy, and drilling rates suggest that one and possibly two sills were penetrated at Site 323, and oceanic basement (layer 2) was not reached. The mineralogy and chemistry are also typical of average mid-ocean ridge basalt although the K2O content is abnormally high. The high oxidation index and abnormally low K-Ar age suggest that the apparent alkalinity of these rocks has been increased during alteration. A possible sill with even stronger alkaline tendencies has been cored at Site 170 (Leg 17) in the central Pacific, and the occurrence of sills with alkaline affinities in deep oceanic basins indicates the oceanic crust may be far more "leaky" than was originally assumed.

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Origin of Pillow Structure in Early Precambrian Lavas of Western Quebec

Cited by 13 publications

References 21 publications

Petrology of Volcanic Rocks Recovered on DSDP Leg 19 from the North Pacific Ocean and the Bering Sea

Petrology of Volcanic Rocks Recovered on DSDP Leg 19 from the North Pacific Ocean and the Bering Sea

Ordovician palaeogeography of the southern and eastern flanks of the Harlech Dome, Merionethshire, North Wales

Petrology and Geochemistry of DSDP Leg 35 Basalts, Bellingshausen Sea

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