The areas investigated are in the Tocantins Province, a Neoproterozoic orogenic area, corresponding to the metasedimentary
fold belts known as the Brasilia and Paraguay fold belts (Pimentel et al.
These rocks form the basement on which the Moine Supergroup and Torridonian sediments were deposited The Moine Supergroup consists of a thick and extensive sequence of Neoproterozoic siliciclastic metasedimentary
rocks, dominated by psammites with subordinate pelites (Mendum et al., 2008).
As in most asbestos deposits found in ophiolites, asbestos orebodies occur about 800 meters from the fault contact separating the enclosing ultramafites from the older metasedimentary
In general, pyroxene-bearing rocks, granites, and granodiorites have higher magnetic susceptibilities than metavolcanic and metasedimentary
rocks (except iron formation) and associated tonalites and diatexites (Pilkington and Percival 1999, 2001; Leclair et al.
rocks are mainly interbedded siltstones, shales, phyllite, and slates.
The oldest rocks exposed in the study area are Paleozoic and Mesozoic metasedimentary
, metavolcanic, and plutonic rocks.
The predominant rocks here are those of volcanic origin, including lavas, tuffs and occasional greenstones, interspersed with calcareous metasedimentary
Our geology crew has unearthed several new interesting sulfide-rich structures associated with amphibolite and metasedimentary
rocks as well as iron formations.
Diamond drilling, at IGO's Andromeda prospect, intersected zinc-bearing sulphides in metasedimentary
rocks and opened a new search space for base metals.
The batholith intruded the Lower Palaeozoic metasedimentary
rocks of the Goldenville, Halifax, and Rockville Notch groups (MacDonald 2001; White 2010a, b, 2012).
Altogether with the gradual increase of metamorphism from the Puncoviscana slates to the La Paya schists, the widespread preservation of metasedimentary
layers in schists and migmatites indicates that the La Paya Formation is derived from the Puncoviscana Formation.
Here, the rarely represented whitish scapolite containing marialite component, locally also dravite, may be indicative of evaporite components in metasedimentary
protolith and/or hydrothermal activity (Kadounova, 1987; Kfibek, 1988; Kfibek et al., 1997; Kfiz, 2009).