The Ootsa 1 area is underlain by andesitic rocks of the Eocene Endako Group and rhyolite and felsic rock of the Eocene to Oligocene Ootsa Lake Group. Geology layers on government website MapPlace (for some map sheets) indicate Endako and Ootsa Lake packages as being formations of the Nechako Plateau Group.
The Ootsa 1 mineral occurrence is underlain by Paleocene and Miocene volcanics and sediments of the Ootsa Lake Group and Endako Group. The Paleocene Ootsa Lake Group rocks are characterized by rhyolitic and dacitic tuff, breccia, shales, sandstone and con- glomerate. The Miocene Endako Group is characterized by basalts, andesites, tuffs, breccias, minor shales and greywackes. All the volcanic and sedimentary rock groups of this area are folded to some degree and practically all folds have a northwest trend.
The mineralization and alteration consists of a zone of quartz and fluorite with potash feldspar and specular hematite alteration. These zones average 75 to 100 metres in width and 300 metres long. The quartz and fluorite generally occur together in veins wider than 5 centimetres, with fluorite occupying the centre of the vein. The fluorite is either cubic or octahedral with individual crystals up to 2 centimetres across. The only sulphide mineralization consists of disseminated pyrite, which occurs in a fine-grained, flow banded and locally brecciated rhyolite. The host rock is an andesite which has undergone propylitic alteration and contains calcite veins which are proximal to the quartz-fluorite vein.
Work History
The first recorded work done in the area was a Geological Survey of Canada mapping program, lead by H.W. Tipper in 1949 (GSC MEM 324).
In 1986 to 1987, Newmont Exploration of Canada Limited reported on some work (geological and geochemical) that they had done in the in the Ootsa 1 flourite area (Assessment Report 16581). They had discovered the fluorite zone but the new road that cuts through the showing had not yet been constructed. Newmont reported anomalous mercury and that arsenic is generally highly anomalous.
During a regional prospecting program in the early 1990s a small fluorite occurrence was discovered in a new road cut just south of Lucas Lake. A few samples were taken from the fluorite showings at that time. One of these was slightly elevated in gold and the area was not considered of interest at that time.
A geophysical survey was completed over the entire Nechako property in 2007 by SJ Geophysics Ltd. for Goldmember Ventures Corporation (Assessment Report 29086). The property surrounds, but does not include, the Ootsa occurrence; however, geophysical results for the occurrence are shown.
In 2009, Ron Bilquist spent 2 days prospecting the Ootsa 1 flourite showing (Assessment Report 31170). He reports on the epithermal potential and prospecting. Clastic rocks are silicified with open spaces lined with tiny quartz crystals. Veins and stockworks of fluorite and quartz occur throughout the entire showing area except for the thin band of sediments. Gold and silver values, although not at economic levels, are significantly anomalous and where the gold is highest the antimony values are elevated.
Geochemical soil sampling and ground magnetometer surveying was done on the occurrence in 2014 by John Buckle of Geological Solutions.
In 2016, six outcrop rock samples were collected along the road access within 200 metres south of the occurrence for the DeCoors Mining Corporation (Assessment Report 36532). No significant gold and silver values were found.
