Abitibi greenstone belt

Tags: archean gabbro diorite gneiss granite greenstone belt neoarchean schist tonalit

Description:

Abitibi greenstone belt of the Superior province of the Canadian Shield. The area consists mostly of felsic to mafic volcanic rocks of Archean age together with related dioritic sills which are concordant to the regional rock formations. These volcanic and intrusive rocks have generally been metamorphosed to the greenschist facies.

The Superior Province is the largest exposed Archean craton in the world and hosts several world class gold deposits. It has yielded nearly 300 million ounces of gold from hundreds of deposits since the beginning of the twentieth century. One prominent characteristic of all significant gold deposits in the Superior Province is their occurrence within or immediately adjacent to greenstone belts. Another characteristic is their occurrence within major tectonic zones which comprise a series of shear zones (Colvine et al., 1988). The Superior Province is divided into four major subprovince types (Card and Ciesielski, 1986): volcano-plutonic, plutonic, metasedimentary, and high metamorphic grade gneiss. The boundaries of these subprovinces are either major dextral, transcurrent, east-striking faults, or zones of structural and metamorphic transition.

The greenstone belts which host the gold deposits occur as east-north-easterly trending ribbon domains in the volcano-plutonic terrains. They typically consist of mafic to ultramafic and felsic metavolcanic rocks, interlayered with metasedimentary rocks. The supracrustal rocks were intruded by syn-volcanic plutons. Saturated and under saturated felsic to mafic igneous rocks intruded into the greenstone belts in late Archean.

The metamorphic grade of most of the present greenstone terrains ranges from sub-greenschist to greenschist facies in the centre, to lower amphibolite facies at the margin. Amphibolite facies contact metamorphic aureoles occur around intrusions into the greenstones (Jolly 1978, 1980) with the exception of the synvolcanic ones.

The Abitibi Greenstone Belt consists of east–west-trending synclines of felsic to ultramafic volcanic rocks. Intervening domes are cored by syn-volcanic tonalite and gabbro-diorite rocks and alternate with east–west-trending bands of late tectonic turbiditic and conglomeratic sedimentary rocks. Most of the volcanic and sedimentary strata dip vertically and are commonly bound by abrupt, east–west-trending faults with varied dips.

The stratigraphy of the Abitibi Greenstone Belt is subdivided into earlier volcanic-dominated episodes that include the Pacaud assemblage (2770–2736 Ma), the Deloro assemblage (2730–2724 Ma), the Stoughton-Roquemaure assemblage (2723–2720 Ma), the Kidd- Munro assemblage (2719–2711 Ma), the Tisdale assemblage (2710–2704 Ma), and the Blake River assemblage (2704–2695 Ma). These sequences are unconformably overlain by turbidites and calc-alkaline volcanic rocks of the Caopatina assemblage (ca. 2700 Ma) in the north and the Porcupine assemblage (2690–2685 Ma) in the south. These units in turn are unconformably overlain by coarse clastic and alkaline volcanic rocks of the Opemisca assemblage (ca. 2692 Ma) in the north and the Timiskaming assemblage (2676– 2670 Ma) in the south.

Deposits

• Name: Wasamac

  Phase: None

  Mine Type: None

  Intro:

  The Wasamac property is located approximately 15 km west-southwest of Rouyn-Noranda, Quebec, Canada, within the central portion of the Abitibi gold mining district. Rouyn-Noranda is serviced by daily flights to Montreal. The Property is accessed from Provincial Highway 117 that links Rouyn-Noranda and the community of Arntfield. A secondary road (Rang des Cavaliers) leads directly to the property from Provincial Highway 117.

  detailed

• Name: Detour Lake

  Phase: Operations

  Mine Type: Pit

  Intro:

  Canada, Ontario. From the town of Cochrane (population of approximately 5,000 residents), the Project is easily accessible by the Detour Lake Mine road, the northern extension of Highway 652. The first 151 km on Highway 652 is paved surface, followed by 34 km of well-maintained chipseal road to the mine site. Road access is available year-round. An airstrip built in 2021 provides access by air to the site. The closest major airport to the site is at Timmins, Ontario, approximately 61 km to the southeast.

  Site topography is subdued with maximum local relief of approximately 30 m. The elevation ranges from approximately 260–288 metres above sea level. There is a pronounced north/south fluting of the landscape consistent with the general direction of the most recent glaciation in this area.

  Areas of higher relief are sparsely wooded with jack pine, black and white spruce, balsam fir, trembling aspen, and white birch. Areas that are slightly lower in relief are poorly drained
  and characterized by muskeg.

  There is very little bedrock outcrop and much of the Project area is overlain by thick accumulations of glacial material that includes till and glaciofluvial material (poorly sorted sand with lenses of gravel).

  Numerous small streams linking elliptical lakes and ponds, generally oriented parallel to the pattern of glacial fluting. Numerous small and shallow lakes are found within the Project
  area, the largest being Sunday Lake, with a surface area of approximately 2.8 km².

  detailed

Mineralizations

No mineralizations available.

Placers

No placers available.