Granite batholith radiometric dating gratis dating for unge Høje-Taastrup
The Meguma terrane of southern Nova Scotia is the most outboard terrane of the Canadian Appalachian Orogen.
The terrane is bounded to the north by the east-trending Cobequid-Chedabucto Fault Zone (CCFZ) that separates this terrane from the Neoproterozoic-Cambrian composite Avalon terrane (Fig. The Meguma terrane consists predominantly of Lower Paleozoic metasedimentary and volcanic rocks that are intruded by Late Devonian metaluminous and peraluminous granite (Clarke 1997).
In the case of the larger intrusions, such as batholiths of thousands of km, it is even more important to constrain their time of emplacement and duration of cooling, as they constitute a large component of the thermal ﬂux of an orogen.
In this paper, we present the ﬁrst high-temperature (i.e., Ar mica ages, which provide the time of cooling through 350– 300°C, that being the time at which argon diffusion in mica ceases (Mc Dougall and Harrison 1988). Radioelement mapping of parts of the Musquodoboit Batholith and Liscomb Complex, Meguma Zone, Nova Scotia.
muscovite et biotite, de 363 à 370 Ma), une datation Rb-Sr de roche totale (266 Ma) et une datation minérale (biotite, 370 Ma).
Ces âges plus précoces contrastent avec les nouvelles données du zircon et de la monazite, qui confèrent ensemble un âge de 378 ± 1 Ma par cristallisation à haute température (c.-à-d.
≥ 3– 4 kilobars).[ Granite batholiths form a large part of tectonic terranes (e.g., Cordillera of North and South America, Appalachian Orogen) and, therefore, constitute an important part of their geological history.
The presence of coarse clastic rocks of the Fammenian Horton Group (Martel 1993), representing the basal part of the overlying Carboniferous stratigraphy, resting on granitic rocks of the SMB indicate that uplift, denudation, and unrooﬁng of the granite intrusions of the Meguma terrane occurred by ~360 Ma.
These earlier ages contrast with new data for zircon and monazite which together deﬁne an age of 378 ± 1 Ma for the high-temperature crystallization (i.e., ca.
650– 800°C) and, therefore, provide a more reliable time for emplacement and solidiﬁcation of the batholith.
The results presented here indicate an age signiﬁcantly older than the Ar mica dates and are discussed in the context of the cooling history of the MB. 1 Geological map of southern Nova Scotia showing the general geology of the Meguma terrane and the location of the Musquodoboit Batholith and other intrusions referred to in the text.
Area indicated as Eastern plutons is referred to in the text and some of these intrusions along with their ages (U-Pb) are summarized in Table 1. Preliminary age study and initial Sr of Nova Scotia granitic rocks by the Rb-Sr whole rock method.
10 à 12 kilomètres) et du gradient géothermique potentiellement élevé en raison de la nature riche en radioéléments de certaines parties du complexe.