La composition chimique d’une roche magmatique dépend de: . roches plutoniques et volcaniques, indique deux maximums, l’un correspondant à des roches. PREMIÈRE. PARTIE. CHAPITRE I. DES QUATRE GRANDES CLASSES DE ROCHES AQUEUSES oU SÉDIMENTAIRES, VOLCANIQUES, PLUTONIQUES ET. les roches volcaniques et plutoniques pdf. Quote. Postby Just» Tue Aug 28, am. Looking for les roches volcaniques et plutoniques pdf. Will be.

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Canadian Journal of Earth Sciences, 6, pp. A rhyolite flow near the top of the formation has yielded a U-Pb zircon age of Ma Dunning et al.

A series of granitic plutons with minor gabbro were emplaced in the Cobequid Shear Zone between — Ma and record progressive dextral transpression with north-vergent thrusting in the shear zone. These ages are consistent with a U-Pb age of Ma on a rhyolite in the lower part of the formation south of New Annan Dunning et al. The distribution of Cumberland Group rocks along the northern margin of the Cobequid Highlands has been mapped by Ryan et al. Late Paleozoic basin formation and deformation along the Avalon-Meguma terrane boundary, Canadian Appalachians.

Tectonic evolution of Fundy basin, Canada: Poor quality U-Pb and Rb-Sr ages of ca. It is lithologically correlated with coastal outcrops of previously unnamed conglomerate east of Squally Point Salas that unconformably overlies the Fountain Lake Group and contains deformed granite clasts. It is manifested by a fundamental change in style of sedimentation between the early and late Devonian. Nd and Pb isotope data show that all the Cobequid Shear Zone granites appear derived from melting of crust compositionally similar to Neoproterozoic granodiorite Pe-Piper and Piper b.

St Julien and J. The Bass River block 8 The Bass River block Nance and Murphy consists of a series of fault slices of Neoproterozoic shelf siliciclastic sedimentary rocks Gamble Brook Formationtectonically juxtaposed with ocean-floor basalt and a thin cover of pelagic sedimentary rocks and fine-grained turbidites Folly River Formation: Les roches magmatiques – PDF ; Les roches volcaniques acides rhyolites sont donc rares.


All these features imply anhydrous melting of lower crust. In contrast, mid Devonian to early Carboniferous rocks of the Murphy Brook Formation, Fountain Lake Group, and Horton Group show rapid changes in facies and thickness, with common occurrence of conglomerate and lacustrine deposits, all suggesting deposition in fault-bound terrestrial basins.

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Rather, there was progressive deformation in the Cobequid Shear Zone, developed along the Minas Geofracture during the convergence of the Avalon and Plutooniques terranes. Devonian — Carboniferous deformation and igneous intrusion in the Cobequid Highlands. Transient cookies are kept in RAM and are deleted either when you close all your browser windows, or when you reboot your computer.

This change in paleogeography resulted from the “Acadian orogeny”, but clear rroches for “Acadian” deformation is lacking. Sedimentologically, the Murphy Brook Formation resembles the lacustrine facies of the Nuttby Formation.

The Falls Formation is older than the late Vis.

The presence of the voluminous Folly Lake gabbro with its associated gravity anomaly and the unusually thick coeval basalt and felsic pyroclastic rocks near the Wentworth pluton both suggest the presence of a major heat source in this area, which resulted in more anhydrous melting here than elsewhere in the Cobequid Shear Zone. We therefore suggest that the Nuttby Formation is of similar age to the type Horton Group, namely latest Devonian to Tournaisian Martel et al.

Elsewhere, such as in Bailey Brook, strata are almost undeformed. Both the Wilson Brook and Portapique River formations are folded and penetratively cleaved to a varying degree. The petrology and geochemistry of an anorthosite suite, Cobequid Highlands, Nova Scotia.

Detailed studies of selected areas are reported in fourteen B.

Microtextures des roches magmatiques et métamorphiques

Similar plutonism in the Antigonish Highlands is regarded as being a little younger — Ma and the — Ma Debert River granodiorite of the Bass River block is younger still. Atlantic Volaniques, 32, pp. Granite and associated mafic phases, North River pluton, Cobequid Highlands. Methods and data 4 This short synopsis of the geology of the Cobequid Highlands is based in part on new 1: Pb and Nd isotope evidence for mantle and lower crustal sources.


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This Neoproterozoic lineament was reactivated in the central Cobequid Highlands, but not in the extreme eastern Cobequid Highlands, where late Paleozoic motion was taken up on the Cobequid and Millsville faults Fig. Smaller intrusive bodies in this area have been termed the River John gabbro, tonalite and granodiorite units Pe-Piper et al. The Neoproterozoic rocks consist of arc volcanic and plutonic rocks and associated sedimentary rocks in two major blocks.

Canadian Journal of Earth Sciences, 35, pp. Il constitue la plus grande Display large image of Figure 5. Geology of the headwaters of the River Philip, Vopcaniques Highlands.

Mylonitic mafic granulite in fault megabreccia at Clarke Head, Nova Scotia: The geology of this area is summarized in Figure 2, showing Upper Paleozoic rocks and Figure 3, showing Neoproterozoic and Lower Paleozoic rocks.

Whether this is plutoniaues result of non-deposition or later erosion is unknown. Email address subscribed successfully. The petrology and geochemistry of iron-oxide deposits within the Cobequid Highlands, Nova Scotia.

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Wilson Brook Formation at Wentworth is almost unde-formed. Display large image of Figure 1 2 The Late Neoproterozoic rocks of the Cobequid Highlands, particularly those of the Jeffers block, show similarities to rocks of comparable age in the Antigonish Highlands Murphy et al. Doig, in Murphy et al. Les roches magmatiques plutoniques Good biostratigraphic and geochronological data are sparse and lateral facies changes are common; hence, correlation between localities is difficult.

Pe-Piper and Murphyand intruded by a series of plutonic rocks Table 1, Fig. Thank you very much. Geology of the Eastern Cobequid Highlands.

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