The Shamrock occurrence is located on a north facing slope, approximately 900 metres north of Newt Lake.

Regionally, the area is underlain by basaltic volcanic rocks of the Upper Triassic Karmutsen Formation (Vancouver Group), which are overlain sequentially by limestone of the Upper Triassic Quatsino Formation (Vancouver Group); limestone, mudstone and siltstone of the Upper Triassic Parson Bay Formation (Bonanza Group) and mixed volcanic and sedimentary rocks of the Lower Jurassic LeMare Lake volcanic unit (Bonanza Group). The volcanic and sedimentary rocks have been intruded by gabbro to quartz diorite of the Lower to Middle Jurassic Island Plutonic Suite.

At the occurrence a narrow rim of skarned, northwest striking, west dipping Lower Jurassic Bonanza Group volcanics lie between Upper Triassic Vancouver Group, Quatsino Formation limestone and diorite of the Lower to Middle Jurassic Island Plutonic Suite.

Scattered outcrops of massive to disseminated magnetite occur at the limestone-volcanic contact over an area of 366 by 30 metres on the north side of the diorite stock. The magnetite is up to 0.9 metre thick and dips 20 degrees west. Locally it is finely laminated, and pyrite content is sometimes high. The massive magnetite occurs lower in the section, with disseminated magnetite occurring higher up. Jefferey (Minister of Mines Annual Report 1960, page 99) suggests that attitudes of the intrusive, the fold structures and bedding in the layered rocks, controlled the position and attitude of the mineralization.

In 1960 and 1961, diamond drilling identified magnetite stockworks and breccia-skarn styles of mineralization. Diamond-drill hole 13 intersected 16 metres of 51 per cent iron. Unclassified reserves were estimated at 180,000 tonnes grading 26 per cent iron (Property File - J. Lamb, 1961, page 9).

Work History

The area has been explored in conjunction with the Merry Widow (MINFILE 092L 044) deposits since the early 1900’s. In 1968, Quatsino Copper Gold completed a program of airborne magnetic and radiometric geophysical surveys on the area. In 1970, Alice Lake Minerals completed an aeromagnetic survey. During 1989, through 1992, Taywin Resources completed programs of geological mapping, trenching and surface sampling on the area. During 2005 through 2012, Grande Portage Resources completed programs of rock, silt and soil sampling, geological mapping, airborne electromagnetic and magnetic surveys and a ground magnetometer survey on the area. In 2016 and 2017, Bridgeland Minerals completed a radar satellite and LiDAR orthophoto geological interpretation program on the area as the Blue Gold/Merry Widow property. In 2019, Mirva Properties Ltd. completed a rock sampling program on the Merry Widow property. In 2020, Roughrider Exploration Ltd. completed a program of rock, silt and soil sampling on the area as the Empire Mine property.