ABSTRACT: Quaternary geology reconnaissance studies 92I/2 and 7.

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Abstract

During the summer of 2001, the British Columbia Geological Survey Branch undertook a 6-day reconnaissance excursion to the Merritt-Logan Lake area of southern British Columbia to evaluate the potential for future regional tillgeochemistry exploration projects. Exploration potential in the area is very attractive, given that this region is already known to host several different types of mineralization including stratiform-base-metal, porphyry and vein targets. The record for previous mining activity in this area includes the prominent Highland Valley Copper and Craigmont mines. More recently, the discovery of ahigh-grade copper-zinc massive sulphide showing on the Fox claims has triggered a minor staking rush in the region. Within a one-year period nearly 1450 claim units had been staked in the vicinity of the Fox claims. Interesting prospects in the proposed study include the LD barite- gold-silver-zinc-lead-copper prospect at Iron Mountain and the Iron King iron prospect south of Nicola Lake. The Quaternary geology of the region has been subject to periodic attention for the last four decades, primarily duringthe process of 1:250,000 scale mapping by the Geological Survey of Canada. Unfortunately, much of the surficial geology work is only relevant at the regional scale and provides minimal insight at a more detailed 1:50,000 scale forthe exploration community. Given the recent economic attraction of this area of the province and the lack of detailed surficial data that is of direct importance to the exploration community, a reconnaissance surficial study was clearlywarranted. A variety of sediment types were observed within the study area at several sites including colluvium, glaciolacustrine, lacustrine, fluvial, glaciofluvial, and numerous till facies. Unequivocally, the dominant material encountered throughout the area is basal till. In this case the basal till is characteristically a well-consolidated, massive, moderately stony matrix supported diamicton. Deposits range in thickness from less than a metre to tens of metres, but typically appear to be about 2-5 metres thick. Clast con-tentvaries from 5% to 35%, and the majority of stones appear to be subangular in shape. Facets and striae are commonly observed on some of the recovered pebbles. Lithologies reflect the surrounding bedrock geology con-firminglocal provenance sources for the entrained debris. Bedrock is exposed in small patches throughout the study, thus facilitating an evaluation of the paleo-ice-flow history for the full region. A few dozen locations yieldedgood evidence for ice flow in the form of striations, rat-tails, grooves, and roche moutonées. Based on the observations conducted in this study it is clear that during the last glaciation ice flowed primarily from the north to the south. Only near the southern margin of the study is there evidence for partial deflection of past ice flow. Little data are currently available for evaluation regardingthe patterns of geochemical distribution in the region. One example of geochemical soil sampling does exist, and is illustrated here to confirm the expected pattern of element dispersion towards the south. Successful long-term historic mining activity and recently discovered exploration targets suggest that this region contains a high potential mineral exploration frame-work. From a Quaternary perspective, the predominance of basal till in the area, the relatively thin nature of the surficial overburden cover and the uniform ice-flow direction over the study area all combine to provide an ideal sampling environment for a regional till geochemistry exploration pro-ject.During the past few decades expanding ranchland and logging activities have opened previously poorly accessible areas between Merritt and Logan Lake to geological exploration. The improved access, good mineral potential andideal surficial nature of the region collectively indicate that a reconnaissance level till geochemistry sampling project in NTS 92I/2 and 92I/7 is both feasible and warranted.

Bibliography of Canadian Geomorphology