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File Created: 22-Feb-2006 by Garry J. Payie (GJP)
Last Edit:  04-Apr-2022 by Karl A. Flower (KAF)

Summary Help Help

NMI
Name CRAGGANMORE, THORN, CUTTY SARK, AMARILLO CREEK Mining Division Atlin
BCGS Map 104K056
Status Showing NTS Map 104K10W
Latitude 058º 33' 30'' UTM 08 (NAD 83)
Longitude 132º 49' 20'' Northing 6492929
Easting 626703
Commodities Gold, Silver, Copper Deposit Types H04 : Epithermal Au-Ag-Cu: high sulphidation
Tectonic Belt Insular Terrane Stikine
Capsule Geology

The Cragganmore zone occurs within a stock (Thorn stock) of feldspar porphyry related to the Late Cretaceous Windy Table Complex. The zone initially was defined as consisting of silicified veins, from 0.1 to 1.0 metre wide, with up to 10 per cent pyrite and enargite. The host porphyry is sericite and clay-altered. One sample over 1 metre yielded 0.78 gram per tonne gold, 37.9 grams per tonne silver and 0.19 per cent copper (Assessment Report 27673).

In 2011, Equity Explorations on behalf of Brixton Metals Corporation reported on the Cragganmore zone. It was first sampled in 2004 during reconnaissance prospecting in La Jaune Creek. More detailed mapping and sampling was completed in 2005 and 2011. This zone comprises a series of small outcrops near the mouth of Amarillo Creek, a large outcrop north and south of Cragganmore Creek, and small outcrops discovered in 2005 exposed within Gossan Creek to the south. Collectively these three areas delineate pyrite-sulphosalt veins over a strike length of 500 metres.

Outcrops at the mouth of Amarillo Creek comprise several silicified vein zones (10 centimetres to 1 metre wide) with up to 10 per cent pyrite and enargite hosted by sericite and clay-altered Thorn Stock. Locally, massive sulphide/sulphosalt (generally with pyrite-enargite) veins are common. Several thinner massive enargite veins are reported but these veins tend to be discontinuous. Sample 276457 was collected near the mouth of Amarillo Creek and returned the highest grade values including 1.19 grams per tonne gold, 198 grams per tonne silver and 12.35 per cent copper (Assessment Report 27673). Although a float sample, this material was derived from a vein in the cliff above.

The main large gossan outcrop was examined again in 2005 and a 15 centimetres wide massive tetrahedrite-enargite-pyrite vein (Cragganmore Vein) was discovered. Sample 378872 of this vein returned 43.6 grams per tonne gold, 519 grams per tonne silver and 24.2 per cent copper (Assessment Report 28151). Adjacent wallrock generally returned only elevated gold and copper. Wallrock adjacent to the vein is strongly altered and PIMA analyses indicate the alteration is characterized by pyrophyllite-dickite-kaolinite. The vein is oriented 321 degrees/62 degrees east and is at an acute angle with the hosting structure. The vein is pod-like within the structure and locally is characterized by siliceous boudins, suggesting that some movement along the fault zone post-dated mineralization and alteration. This vein resembles the veins within the F zone (104K 116).

In Gossan Creek to the south, several thin (<5 centimetres), planar, veins of quartz-pyrite-tetrahedrite-pyrargyrite are hosted in strongly sericite-clay altered Thorn Stock, including sample 378748 (below). A sub-parallel, thin barite vein (0.5 to 3.0 centimetres) was noted in the same outcrop. New mapping at the Cragganmore indicates that the two main Cragganmore outcrops are part of the same 50 m wide fault / vein structure which strikes northwest and dips steeply and is interpreted to be the northern extension of the La Jaune Fault. Locally high-grade veins are present in this structure, highlighted by a 15 centimetres sample of enargite-pyrite which assayed 43.6 grams per tonne gold, 519 grams per tonne silver and 24 per cent copper (Assessment Report 28151).

At the northern Cragganmore outcrop, a wedge of strongly sericite-silica altered and pyritized Stuhini sedimentary rock is caught up in the fault, supporting the idea that this structure was active during the high-sulphidation veining episode.

The Cutty Sark zone is located on the north side of La Jaune Creek, approximately 400 metres northwest of the Cragganmore zone. The zone comprises a triple junction between the Thorn Stock, Stuhini Group mafic volcanic rocks and siltstone, or possible re-sedimented volcaniclastic rocks of the Windy Table Group. Mineralization consists of three main lenses of semi-massive to massive coarse-grained pyrite and silica hosted by strongly sericite-clay-silica altered Thorn Stock. The lenses are up to 0.6-metre wide and have been exposed for approximately 15 metres along strike. The pyritic zones generally dip shallowly (approximately 30 degrees) and strike north- northeast while a planar pyritic replacement zone is oriented at 195 degrees and dips 75 degrees west.

North of the Cragganmore zone in Amarillo Creek float samples containing coarse crystalline, white-grey barite and lesser clear quartz with 1 per cent pyrite, 1 per cent tetrahedrite and traces of visible gold have been identified. The vein was hosted by a medium-grained, feldspar-phyric porphyritic wallrock that is strongly sericitized. In 2004 and 2005, float samples (626650 and 378704) yielded 265 and 250 grams per tonne gold, 631 and 506 grams per tonne silver with 0.233 and 0.204 per cent lead, respectively (Baker, D. (2010-10-28): 2010 Technical Report on the Thorn Property).

Work History

In 2004, Cangold Limited and Rimfire Minerals discovered the Cragganmore occurrence. See Thorn (104K 031) for further details of the larger Thorn property.

Bibliography
EMPR AR 1963-6; 1964-11; 1965-17
EMPR EXPL 1981-242; 1983-546; 1999-19-31; 2000-1-8; 2003-6; 2004-26; 2005-28
MER 2003-16; 2004-13; 2005-7
EMPR OF 1998-8-E, pp. 1-25
EMPR PF (Offering of Rights. Consolidated Inland Recovery Group Ltd.; Rimfire Minerals Corporation Website (Feb.2000))
GSC MAP 6-1960; 1262A
GSC MEM 362, p. 56
GCNL #183, 1968; #57,#139, 1986; #128(Jul.5), #196(Oct.13), 2000
N MINER Aug.12, Dec.2, 2002; Oct.28, Sept.8,25, 2003
PR REL Cangold Limited (First Strategies Au Corp.), Jan.17 2002; Oct.10, 2002; Apr.3, May15, Jun.5; Jun.29, Sept.24, 2003; Rimfire Minerals Corp., Mar.26, Jul.15, Dec.5, 2002; Jun.9, Nov.12,24, Dec.18, 2003; Jun.29, 2005; Rimfire Minerals Corp. and Cangold Limited Oct.10, 2002; Jun.24, Aug.27, Sept.25, Oct.27; Jun.4, Aug.4, Sept.27, Nov.18, 2004; Jan.7, Jun.6, Jul.26, Aug.8, 2005
*Baker, D. (2010-10-28): 2010 Technical Report on the Thorn Property
Burrell, H., Deiss, A.M. (2021-06-23): Thorn Property NI 43-101 Technical Report Sutlahine River Area, British Columbia, Atlin Mining Division

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