Dayohessarah Greenstone Belt

Tags: albitization almandine batholith biotization carbonatization diopsidation dyke granodiorite porphyry greenstone belt monzogranite pluton pyrope quartz monzodiorite quartz monzonite silicification sill tonalit upper archean

Description:

The Dayohessarah Greenstone Belt of late Archean (ca. 2.7 Ga) age is located in the AbitibiWawa Subprovince of the Superior Province. The Dayohessarah Belt is positioned between two larger greenstone belts; the Hemlo Belt to the west and the Kabinakagami Belt to the east. The Dayohessarah Greenstone Belt trends broadly north and forms a narrow, eastward concave crescent. The belt is approximately 36 km in length and varies in width from 1.5 to 5.5 km. Principal lithologies in the belt are moderately to highly deformed metamorphosed volcanics, volcanoclastics and sediments that have been enclosed and intruded by tonalitic to granodioritic quartz-porphyry plutons.

The greenstone belt is bordered to the east by the Strickland Pluton and to the west by the Black Pic Batholith. The Danny Lake Stock borders the south western edge of the Dayohessarah Greenstone Belt. The Strickland Pluton is characterized by a granodioritic composition, quartz phenocrysts, fine-grained titanite, and hematitic fractures. The Black Pic Batholith is similar to the Strickland Pluton, but locally more potassic with monzogranite phases. The Danny Lake Stock is characterized by hornblende porphyritic quartz monzonite to quartz monzodiorite (Stott, 1999).

The Dayohessarah Greenstone Belt has been metamorphosed to upper greenschist to amphibolite facies. The Strickland Pluton seems to have been emplaced into the greenstone belt and imposed a thermal metamorphic event. Most of the mafic volcanics are composed primarily of plagioclase and hornblende. Almandine garnets are widely observed in the clastic metasediments and locally pyrope garnets are present in the mafic metavolcanics (Stott, 1996).

Alteration throughout the belt consists of diopsidation, albitization, weak magnesium biotization, weak carbonatization and moderate to strong silicification that accompanied the emplacement of the porphyry dykes/sills and quartz veining. The belt has been strongly foliated, flattened and strained. Deformation seen in the supracrustal rocks has been interpreted to be related to the emplacement of the Strickland Pluton. Strongly developed metamorphic mineral lineations in the supracrustal rocks closely compare with the orientations of the quartz phenocryst lineations seen in the Strickland Pluton. This probably reflects a constant strain aureole imposed by the pluton upon the belt (Stott, 1996). The strain fabric is best observed a few hundred metres from the Strickland Pluton in the Sugar Zone, which has been characterized as the most intensely strained part of the belt. The Sugar Zone is defined by sets of parallel mineralized quartz veining, quartz flooding of strongly altered wall rock, thin intermediate porphyry lenses and dykes/sills parallel to stratigraphy and foliation, and gold mineralization.

Stratigraphic layering and top indicators define a synclinal fold in the central portion of the belt. The synclinal fold has been strongly flattened and stands upright with the fold hinge open to the south and centered along Dayohessarah Lake.

Regional geology map:

Airborne em/magnetic survey results and priority targets:

Deposits

• Name: Sugar zone

  Phase: Operations

  Mine Type: underground

  Intro:

  Canada. The Sugar Zone Property is located 30 km northeast of the town of White River in northern Ontario. White River is located on Trans-Canada Highway 17 approximately midway between Thunder Bay, 315 km west, and Sault Ste. Marie, 260 km southeast. The Operation is approximately 715 km northwest of Toronto and 68 km east of the Hemlo Gold Camp, Ontario.
  The Sugar Zone Deposit is located in UTM Zone 16UNAD83 at 646,140 m E, 5,406,900 m N or 48° 47' 53" North latitude and 85° 00' 36" West longitude. The overall Property encompasses NTS Zones 42C/ 10, 11, 14 and 15 and covers portions of Odium, Strickland, Gourlay, Tedder, Abraham Bayfield, Cooper, Johns, Nameigos, Mosambik and Hambleton Townships and falls within the Sault Ste.

  detailed

Mineralizations

No mineralizations available.

Placers

No placers available.