Petrogenesis of a porphyritic granite east of Oporto (Portugal)

Schermerhorn, L. J. G.

doi:10.1007/bf01128031

Cited by 9 publications

(1 citation statement)

References 5 publications

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“…Growth relations among primary accessory minerals (Fig. 3); broken or incomplete, supposedly primary magmatic minerals, in otherwise undeformed host rocks (protoclasis); preferential distribution of primary accessory minerals among primary biotite and amphibole; relict delicate oscillatory zoning in plagioclase; altered pyroxene cores in primary amphibole; and a zonal arrangement of biotite in potassium feldspar, appear to support the interpretation (Frasl 1954;Schermerhorn 1956;Taubeneck 1967). Age determinations by the University of Alberta on Western granodiorite complex rocks indicate intrusion 1900 m.y.…”

Section: The Western Granodiorite Complexsupporting

confidence: 51%

On the geology and geochronology of northwestern Saskatchewan. I. Tazin lake region

Koster¹,

Baadsgaard²

1970

Can. J. Earth Sci.

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The rocks of the Tazin Lake region, north of Lake Athabasca, have been subdivided into three major complexes: the Northeastern basement complex, mainly composed of a syn-to-late tectonic granodiorite-diorite series ; a central meta-sedimentary and gneissic belt ; and the Western granodiorite complex. Mylonitization, folding, and faulting are common in the centrally located meta-sedimentary and gneissic belt. Twenty new radiometric age determinations by the K-Ar method on biotite and amphibole of the granodiorite-diorite series average 2370 + 40 m.y. Fragmentation of late tectonic basic dikes and remobilization of the granodiorite-diorite series have been provisionally correlated with this established minimum age. The Western granodiorite complex was intruded 1900 m.y. ago. One biotite sample from White Lake granite of the meta-sedimentary and gneissic belt indicates an apparent K-Ar age of 1800 m.y.

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Section: The Western Granodiorite Complexsupporting

confidence: 51%

On the geology and geochronology of northwestern Saskatchewan. I. Tazin lake region

Koster¹,

Baadsgaard²

1970

Can. J. Earth Sci.

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On the torridonian sediments of colonsay and their relationship to the main outcrop in north‐west Scotland

Stewart

1962

Geological Journal

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Colonsay is a small island in the Inner Hebrides, about 100 km. south of Skye. The main part of the succession, which is about 2 km. thick, consists of phyllites, fine dark sandstones and flags, occasionally graded, with major intercalations of coarse current-bedded arkose and, near the top, dolomitic limestone horizons. This series rests with a sharp cuntact (probably a slight unconformity) on a sequence of graded greywackes and mudstones, not less than 2 km. thick, most of which outcrops to the south in Oronsay, and in Islay, where it rests unconformably on the Lewisian basement. The greywackes and arkoses indicate that currents moved mainly northeastwards.

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50 Jahre Granitforschung

Mehnert¹

1987

Geol Rundsch

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ZusammenfassungEs wird versucht, die Entwicklung des Granitproblems in unserem Jahrhundert aus heutiger Sicht zu schildern. Dabei wird die grol~e Diskussion zwischen den Vertretern der magmatischen Granitbildung und den Anh~ingern einer metasomatischen Granitisation in den Mittelpunkt gerfickt. Die Argumente in der einen und anderen Richtung werden diskutiert und vor allem vom petrographisch-geochemischen Standpunkt gegeneinander abgewogen. Es wird darauf hingewiesen, dai~ das Gewicht sich in den letzten Jahrzehnten immer mehr zu Gunsten einer magmatischen Entstehung des Granits und gegen eine weitr~iumige Granitisation verschoben hat. Aber es wird auch betont, dat~ relativ kleinr~iumige Blastesen vor allem im sp~iteren, niedrlg-temperierten TeiI der Granitbildung eine Rolle spielen. AbstractAn attempt is made to follow the complex history of the granite problem in our century. The great discussions between the proponents of the magmatic conception and the followers of a Iong-distance metasomatic granitization are depicted. The arguments advanced in both directions are discussed and compared with each other mainly from the petrographical and geochemical points of view. There can be no doubt that the magmatic concept of granite formation has steadily advanced during the last decades, whilst the arguments in favor of the granitization theory have lost in weight. However, it should be emphasized that the principles supposed to govern the granitization concept are still valid, even if only evident in small scale processes, for instance in short-distance diffusions occurring mainly in the lowgrade postmagmatic stage of granite formation.

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Petrogenesis of a porphyritic granite east of Oporto (Portugal)

Cited by 9 publications

References 5 publications

On the geology and geochronology of northwestern Saskatchewan. I. Tazin lake region

On the geology and geochronology of northwestern Saskatchewan. I. Tazin lake region

On the torridonian sediments of colonsay and their relationship to the main outcrop in north‐west Scotland

50 Jahre Granitforschung

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