Most Quebrada de Humahuaca fabrics, from Coctaca, Pucara de Tilcara, Pucara de Perchel and Esquina de Huajra, were very similar, comprising 20-30 per cent generally rounded altered pelites
, rare sandstone grains, abundant quartz and rounded plagioclase (Figure 6a).
In the study area, the outcropping lithologies were grouped into nineteen classes: 1--lower Ordovician sedimentary rocks, 2--Devonian conglomerates, sandstones and pelites
, 3,4,5 and 6--carboniferous marine formations, 7, 10 and 11--granites, 8--granodiorites, 9--rhyolites, 12--mesosilicic and silicic volcanic and igneous complex, 13--multicolor tuff, 14--Miocene intrusive rocks, 15--Miocene argillites, 16 and 17--Pleistocene deposits, 18--silt, and 19--recent deposits.
Drill hole CRE084 has only minor overlying sandstone alteration, but there is significant alteration in the basement within graphitic pelite
A similar situation occurs in the McArthur River deposit where the P2 fault thrusts basement pelites
into the overlying Athabasca Group sediments (Figure 2).
The first drill hole for the winter program, BLK001, went directly into basement and intersected intensely mylonitic graphitic pelites
This is in marked contrast to most anchizone cleavages described in the literature (see Kisch 1991), which are regarded as the precursors to the slaty cleavage that is more fully developed in higher grade anchizonal and greenschist facies pelites
Sedimentary Iron formations (BIF) A A deposits Oolitic iron A A Sedimentary phosphates K K Manganese deposits A A Barite in black shales K K Diagenetic Copper in pelites
K A deposits Uranium sandstones K K Discordant uranium A ?
The fine-grained sedimentary rocks - mudstones, shales and pelites
- occur very widely: it is clear that a number of different sources may have been exploited (see Mandal et al.
The drilling was designed to test a broad zone of low-grade gold mineralization hosted within a sequence of thinly bedded pelites
and lesser phyllites and characterized by finely disseminated arsenopyrite-pyrrhotite-pyrite mineralization and numerous narrow quartz veinlets and stringers.
In the basement rocks the drill hole intersected strongly-graphitic pelites
with one section from 909.
are widely developed in the southeastern part of the area and are locally present within the Cranberry Point Shear Zone.
The Boka Gold Project is a newly discovered area of high-grade gold mineralization occurring within horizontal to gently east dipping calcareous siltstones, carbonacerous pelites
and dolomite breccias belonging to the Middle Proterozoic Heishan Formation.