Regional Sampling programs across Lena West have recovered widespread KIMs with good diamond association chemistry including 18 diamonds. There is evidence that many of the KIMs recovered in the western side of the Lena West are derived from secondary concentrations at the base of the Cretaceous sediments with a likely primary source to the east, probably outside the basin along the diamond corridor. KIMs both within and outside the Cretaceous basin were redistributed by glaciation.
The regional KIMs across the Lena West differ from those of the Darnley Bay kimberlites, but are similar to those of the Dharma kimberlites. The latter kimberlites are small and have a limited range of KIM compositions so cannot be the source of all the Lena West KIMs. Cluster analysis confirms that KIMs in the Horton area have compositions that cover the full range of those found across Lena West and the differ from those at Darnley Bay and Dharma.
Ferricrete ("Latrite") cobbles occur in tills in Talmora's project area especially down-ice of magnetic anomalies and appear to be of local origin. Together with diagenetic alteration of KIMs and apparent distruction of silicate KIMs they are evidence of a humid and tropical climate in the Talmora area that probably coincides with the Eocene Thermal Maximum (55Ma). A recent surficial map released by the GSC (2013) shows areas of regolith (ferricrete) within in the Talmora area. Located on the flanks of the unglaciated Melville Hills glaciation has not completely removed the weathered zone.
Numerous magnetic targets on the Talmora property show characteristics of weathered kimberlite pipes. Over forty of them have associated KIMs down-ice (mostly chomite and ilmenite). The magnetic anomalies have relatively low amplitude and as expected in deeply weathered kimberlites, in which magnetite alters to hematite and iron-hydroxides show little evidence of remnant magnetism.
The tops of two targets were successfully investigated with a small Packsack drill. The holes penetrated through about 10 vertical metres of glacial overburden and ended 1 to 2 metres in compact rusty coloured clay.
A 25mm section of clay was recovered with a composition similar to weathered kimberlite from Sierra Leone. Drill cuttings from one hole contained thirteen chromites, one picroilmenite , and fourteen altered and five fresh Mn-ilmenites with diamond inclusion chemistry. Chromite compositions lie on a very narrow Fe/Mg crystalization trend line indicating a single population and nearby source.
There is evidence that Talmora could hold the source area of the Lena West KIMs and diamonds. A larger drill is required to obtain fresh kimberlite and sufficient core for microdiamond analysis
(The above project outline was adapted from the abstract and oral presentation entitled: Davies, A,W. and Davies, R. (2016), Talmora Diamond Inc. - Horton River Project Update; in Irwin et al (compilers) 2016 44th Annual Yellowknife Geoscience Forum Abstracts, Northwest Territories Geological Survey, Yellowknife, NT, YKGSF Abstracts Volume 2016)
The original NI43-101 for the project can be found on www.sedar.ca.