Title of article :
Time-scales of assembly and thermal history of a composite felsic pluton: constraints from the Emerald Lake area, northern Canadian Cordillera, Yukon
Author/Authors :
Coulson، نويسنده , , Ian M and Villeneuve، نويسنده , , Mike E and Dipple، نويسنده , , Gregory M and Duncan، نويسنده , , Robert A and Russell، نويسنده , , James K and Mortensen، نويسنده , , James K، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2002
Pages :
26
From page :
331
To page :
356
Abstract :
Knowledge of the time-scales of emplacement and thermal history during assembly of composite felsic plutons in the shallow crust are critical to deciphering the processes of crustal growth and magma chamber development. Detailed petrological and chemical study of the mid-Cretaceous, composite Emerald Lake pluton, from the northern Canadian Cordillera, Yukon Territory, coupled with U–Pb and 40Ar/39Ar geochronology, indicates that this pluton was intruded as a series of magmatic pulses. Intrusion of these pulses produced a strong petrological zonation from augite syenite, hornblende quartz syenite and monzonite, to biotite granite. Our data further indicate that multiple phases were emplaced and cooled to below the mineral closure temperatures over a time-scale on the order of the resolution of the 40Ar/39Ar technique (∼1 Myr), and that emplacement occurred at 94.3 Ma. Simple thermal modelling and heat conduction calculations were used to further constrain the temporal relationships within the intrusion. These calculations are consistent with the geochronology and show that emplacement and cooling were complete in less than 100 kyr and probably 70±5 kyr. These results demonstrate that production, transport and emplacement of the different phases of the Emerald Lake pluton occurred essentially simultaneously, and that these processes must also have been closely related in time and space. By analogy, these results provide insights into the assembly and petrogenesis of other complex intrusions and ultimately lead to an understanding of the processes involved in crustal development.
Keywords :
Ar-40/Ar-39 , thermochronology , Emerald Lake pluton , Mid-Cretaceous , U–Pb
Journal title :
Journal of Volcanology and Geothermal Research
Serial Year :
2002
Journal title :
Journal of Volcanology and Geothermal Research
Record number :
2243530
Link To Document :
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