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TitreReport on 1982 temperature gradient drilling on Shovelnose Creek at Mount Cayley, southwestern British Columbia
AuteurReader, J F; Croft, S A S; Nevin Sadlier-Brown Goodbrand
SourceCommission géologique du Canada, Dossier public 1017, 1984, 40 pages (3 feuilles), (Accès ouvert)
ÉditeurCommission géologique du Canada
Documentdossier public
CartesCette publication contient 1 carte
Info. cartelocalisation, 1/50,000
Mediapapier; en ligne; numérique
Lat/Long OENS-123.5000 -123.0000 50.2500 50.0000
Sujetstrous de mine; gradient géothermique; eaux de surface; gaz carbonique; sondage au diamant; trous de forage; plutons; filons rocheux; système hydrothermal; ensembles volcaniques; altération hydrothermale; eau souterraine; Complexe de Mount Cayley ; géochimie; Phanérozoïque; Cénozoïque; Quaternaire
Illustrationslocation maps; columnar sections; drillhole logs; profiles; tables
Diffusé1984 05 01; 2017 03 07
Résumé(Sommaire disponible en anglais seulement)
During August-September, 1982, Nevin Sadlier-Brown Goodbrand Ltd. on behalf of the Geological Survey of Canada, managed a helicopter-supported, geothermal gradient drilling program at the Mount Cayley volcanic Complex in southwestern British Columbia. The drill site was located at elevation 1540m in the upper reaches of Shovelnose Creek which drains the southeastern side of the Complex. Using diamond drilling equipment, one hole (Shovelnose One) was abandoned at 516' ( 15 7. 3m) when rods were stuck in the hole during cementing to alleviate severe hole conditions. After moving the rig by hand, Shovelnose Two was completed uneventfully to 1500' (457.3m). The holes penetrated a quartz diorite of the Coast Plutonic Complex cut by at least three stages of volcanic intrusion. Numerous dykes of dacitic and andesitic composition are visible throughout the core. Alteration and precipitate assemblages are typical of extensive hydrothermal activity similar to that at the Meager Creek volcanic complex to the north. The highest temperature measured was 48 .9°C at total depth in Shovelnose Two. Measured gradients display the influence of a warm water flow which enters the hole at 835' (254.6m). A background thermal gradient of approximately 95°C/km is interpreted from the bottom hole temperatures. Water from the flowing zone was sampled at the surface and is seen to be highly saline with Na , c1-, Mg++, HC03 - being the dominant ions. A clear, colourless, non-flammable gas observed bubbling up the well is assumed to be dominantly carbon dioxide. Geothermometer estimates are variable with the most encouraging being the quartz conductive model which yields temperatures of 85.3°C and 115.7°C in two samples. Chalcedony precipitation and surface groundwater dilution probably yield a lower estimate of equilibrium temperatures.