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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C’est le cas des roches volcaniques. All these features imply anhydrous melting of lower crust.
Géologie du Massif central — Wikipédia
The Bass River block, in the southeast, shows evidence of shear-zone emplacement of a suite of plutonic rocks ranging from gabbro to granodiorite to granite into tectonically juxtaposed ocean floor volcanic and shelf sedimentary rocks.
Mineral occurrences in the Cobequid Highlands. Both the Wilson Brook and Portapique Volcaniqies formations are folded and penetratively plktoniques to a varying degree. All mainstream modern browsers have cookies enabled by default, so if you’ve been directed to this page volcanques probably means you’re uisng a weird and wonderful browser of your own choosing, or have disabled cookies yourself.
The highlands are dominated by E—W trending faults of the Late Paleozoic Cobequid Shear Zone, which developed during oblique convergence between the Avalon and Meguma terranes, and which facilitated the emplacement of gabbro and granite plutons and their extrusive equivalents Fountain Lake Group in the latest Devonian — earliest Carboniferous.
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Jeffers Group rocks are also recognised in the River Philip area Fig. Rather, there was progressive deformation in the Cobequid Shear Zone, developed along the Minas Geofracture during the convergence of the Avalon and Meguma terranes. Such rapid changes in degree of deformation suggest that deformation was related to regional shear. Who could help me? Devonian — Carboniferous deformation and igneous intrusion in the Cobequid Highlands. There is no geochemical or petrological evidence for any dykes of Jurassic age among the dykes for which we have geochemical analyses Piper et al.
These two contrasting formations imply original deposition in distant basins now juxtaposed by thrusting and strike-slip motion. The Silurian Wilson Brook and early Devonian Portapique River formations were deposited regionally over at least km of the Cobequid Highlands and almost identical facies are recognised 50 km farther east at Arisaig.
Geologi cal Survey of Canada Open File90 p. Geological Survey of Canada Bulletin61 p. In the Mount Thom area, the Jeffers block shows a major shear zone contact with the Bass River block that has been unaffected by late Paleozoic deformation Pe-Piper et al.
Chronology of Devonian to early Carboniferous rifting and igneous activity in southern Magdalen Basin based on U-Pb zircon dating. Atlantic Geology, 29, pp. The field notes and plotting sheets of Donohoe and Wallace are available through the N. Much of the Cobequid Highlands is underlain by latest Devonian — earliest Carboniferous granite and gabbro plutons and their extrusive equivalents, the Fountain Lake Group.
Donohoe plutkniques Wallaceidentified two possible Ordovician rock units. The stratigraphic section in the Cobequid Highlands is summarized in Table 1.
Late Devonian — Early Carboniferous plutonic rocks 27 Much of the Cobequid Highlands is underlain by plutonic rocks of latest Devonian to earliest Carboniferous age. L’origine des roches – Province of Manitoba ; Penses-y Early Carboniferous gabbro and basalt in the St.
les roches volcaniques et plutoniques pdf
Earth and Planetary Science Letters,pp. Whether this is the result plhtoniques non-deposition or later erosion is unknown. Geology of the northern Antigonish Highlands, Nova Scotia. 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. A activation email has been sent to you. The Cobequid Highlands thus differ from Avalonian successions in eastern Newfoundland, Cape Breton Island, the Antigonish Highlands and southern New Brunswick in lacking Cambrian—Ordovician overstep shelfal sequences with characteristic Avalonian fossils.
The Jeffers block 11 The Jeffers block consists principally of the Jeffers Group, a series of volcanic and volcaniclastic sedimentary rocks at least several hundred metres thick Pe-Piper and Piper Atlantic Geology, 32, pp.
Faults at a high angle to the E—W master faults generally appear to terminate against them, although in places there may volcaniqurs NNW-trending faults that offset these major faults. The youngest stratified rocks in the Cobequid Highlands comprise fluvial and lacustrine sedimentary rocks of the latest Devonian — Tournaisian Horton Group, which accumulated in fault-bound basins.
Canadian Journal of Earth Sciences, 26, pp. The Jeffers Brook Pluton shows synmagmatic deformation features near its southwestern margin, much of the pluton shows a weak ductile solid-state foliation, and mafic enclaves tend to be flattened.
Sparse inland outcrops north of Advocate of similar conglomerate are also assigned to the Falls Formation. A rhyolite flow near the top of the formation has yielded a U-Pb zircon age of Ma Dunning et al.
The first two units occur principally as sheets tens to hundreds of metres thick within the Gamble Brook Formation, with structures indicating emplacement during shearing Pe-Piper et al. Metamorphism of the Bass River block is of greenschist facies, with sparse evidence locally of higher grades adjacent to mafic and intermediate plutons.
Display large image of Figure 3. Pe-Piper and Murphyand intruded by a series of plutonic rocks Table 1, Fig. 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. The Cobequid Highlands include the only thick early Carboniferous basalt succession in Atlantic Canada, overlying several kilometres of latest Devonian rhyolite.
Unlike other blocks or terranes in eastern Canadian Avalonion, the Bass River block lacks volcanic rocks synchronous with Late Neoproterozoic plutons, suggesting that it represents a deeper crustal level. On its northern side is the large Cape Chignecto pluton in the west and a series of smaller plutons to the east. Detailed studies of selected areas are reported in fourteen B.