Airborne gravity, EM and magnetic survey over the Paulatuk gravity anomaly

This entry was posted by Wednesday, 3 March, 2010
Read the rest of this entry »
FacebookTwitterGoogle+Share

Darnley Bay Resources has outlined its 2010 exploration plans for its properties in the Paulatuk NT area. It has completed permitting for airborne surveys to take place in March-April 2010.

Sander Geophysics is preparing to mobilize to Paulatuk for a 5,980 line-km airborne gravity and magnetic survey covering all of the Darnley’s Bay properties where they encompass the Darnley Bay Gravity Anomaly. The purpose of the survey is to significantly improve the resolution of the previous ground gravity surveys over the Anomaly and to locate targets for drilling.
Geotech Ltd.  is preparing to mobilize to Paulatuk for a 2,600 line-km airborne VTEM time-domain electromagnetic and magnetic survey covering all of the eastern and northeastern portion of the Company’s properties, where previous sampling and airborne surveys indicate the presence of gabbro sills and dykes.

outline its 2010 exploration plans for its properties in the Paulatuk NT area. It has completed permitting for airborne surveys to take place in March-April 2010.

Paulatuk gravity anomalyThe Geological Survey of Canada (GSC) conducted a regional gravity survey in 1969 as part of its national gravity coverage providing readings at 2.5 km (1.55 miles) to 20 km (12.4 miles) intervals over and surrounding the area of Paulatuk; it discovered the gravity anomaly. In 1970 the Dominion Observatory published the Inuvik-Horton River map sheet. Northgate Exploration Limited flew a helicopter-borne magnetic survey over the most intensive part of the gravity anomaly and detected a coincident magnetic anomaly. A number of seismic profiles were surveyed in the early 1970’s on the western portion of the AMI, most of these are located on the western sedimentary platform. They identified a deep 6-800 metres trough (NW) along the west margin of the dyke swarm, the significance of which is still unknown. The GSC undertook an aeromagnetic survey over the positive gravity anomaly. The survey was flown along north-south oriented flight lines spaced 2 km apart, at a constant height of 610 metres (2,000 feet) above sea level. It defined the positive magnetic anomaly (detected by Northgate in 1970) at 1200 nT amplitude, coincident with the gravity anomaly. The GSC collected samples from a number of basic sills east of the anomaly that contained minor amounts of nickel, copper, platinum, gold, silver and cobalt. These rocks and metallics may be genetically associated with the anomaly. The GSC suggests that the cause of the anomaly (130mGal) may be an igneous intrusive similar to that in the Sudbury Basin, Ontario (30 mGals), Norilsk in Russia (25 mGals), and the Bushveld Complex in South Africa (65 mGals). Ref: GSC Open File Report 2789. The DBR 1997 aeromagnetic survey indicated that the main intrusive has 4 upward extending feeder pipes. The feeder pipes give way to 9 laterally trending shallow magnetic zones, which are referred to as “offshoots” being drill targets for mineral deposits. The aeromagnetic survey in the central portion of the Anomaly, revealed a number of kimberlite targets. These targets could have conveyed diamonds and also fragments of sulphide mineralization to the surface revealing the composition of the Anomaly and the possible presence of Ni, Cu, PGE. DBR carried out ground geophysical surveys on the Thrasher Zone, which revealed 5 electromagnetic conductors within 250 metres of the surface that have coincident gravity and magnetic responses, 3 of the conductors are horizontal and 2 are vertical. The 2 vertical conductors are along fault structures that represent conductive shear zones and possible associated mineralization. They have strike lengths of 1,500 metres, widths of 450-800 metres and are centered 250 metres below surface. (Source http://www.darnleybay.com)

(Visited 297 times, 1 visits today)

Comments are closed.