PorterGeo
SEARCH  GO BACK  SUMMARY  REFERENCES
Palmeiropolis

Tocantins, Brazil

Main commodities: Zn Cu Pb Ag
Our International
Study Tour Series
The last tour was
OzGold 2019
Our Global Perspective
Series books include:
Click Here
Super Porphyry Cu and Au

Click Here
IOCG Deposits - 70 papers
All available as eBOOKS
Remaining HARD COPIES on
sale. No hard copy book more than  AUD $44.00 (incl. GST)
Big discount all books !!!


The Palmeirópolis Zn-Cu-Pb massive sulphide deposits are located in north-central Goias State, Brazil.

The host Palaeoproterozoic Palmeiropolis sequence is part of a north-east trending volcano-sedimentary belt situated along the western border of the major basic-ultrabasic intrusive bodies of the Goias Massif.

Zn-Cu-Pb massive sulphide deposits with underlying zones of hydrothermal alteration embracing stringer type Cu alteration are associated with a thick sequence of basic meta-volcanic rocks (now represented by amphibolites).

The host sequence and alteration in the immediate ore zone may be generalised as follows, from the base:
* Dark green, finely granular, hornblende-plagioclase amphibolite;
* Medium grained, garnet-biotite-amphibolite with pyrrhotite and pyrite developed in the foliation, and variable disseminated chalcopyrite within fractures. This zone may be around 5 m thick.
* Anthophyllite and biotite rock, with variable garnet and staurolite. It is medium grained, with a poorly developed foliation. Disseminated sulphides are found on fractures, largely near the contact with the massive sulphide body. These include chalcopyrite, sphalerite, pyrrhotite and pyrite. This interval may be around 10 to 15 m thick.
* Massive sulphides, which are approximately 2 to 3 m thick in the smaller C-1 and C-2 deposits. Predominantly composed of sphalerite, chalcopyrite, pyrrhotite, pyrite and galena, the massive sulphides are brecciated, and encompass fragments of the enclosing wall rock lithologies.
* Hangingwall amphibolite.

Reserves in the bodies outlined to date total around 5 Mt @ 4.3% Zn, 1.2% Cu, 0.7% Pb, 25 g/t Ag.   The largest deposit, C-3, contains 2 Mt @ 4.05% Zn, 1.38% Cu, 0.28% Pb, while C-1 totals 0.75 Mt @ 5.2% Zn, 1.25% Cu, 1.38% Pb, and C-2 has 0.33 Mt @ 5.8% Zn, 0.46% Cu, 1.178% Pb.

The three known orebodies have a similar ore mineralogy, comprising pyrrhotite and pyrite with associated sphalerite, chalcopyrite and galena. Alteration zones formed by anthophyllite, biotite and cordierite-bearing rocks are apparently related to the massive sulphides. The orebodies are interpreted to have been modified by the deformation which accompanied metamorphism.

The preceding is drawn from Aruajo & Nilson (1988).

For more detail consult the reference(s) listed below.

The most recent source geological information used to prepare this summary was dated: 1999.    
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd.   Unauthorised copying, reproduction, storage or dissemination prohibited.


  References & Additional Information
   Selected References:
Araujo S M  1999 - The Palmeiropolis volcanogenic massive sulfide deposit, Tocantins State: in Silva M G, Misi A (Ed.), 1999 Base Metal Deposits of Brazil CPRM, Brazil    pp 64-74
Araujo S M, Scott S D  1996 - Oxygen isotope composition of alteration zones of highly metamorphosed volcanogenic massive sulfide deposits: Geco, Canada, and Palmeiropolis, Brazil: in    Econ. Geol.   v91 pp 697-712


Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge.   It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published.   While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo takes no responsibility what-so-ever for inaccurate or out of date data, information or interpretations.

Top | Search Again | PGC Home | Terms & Conditions

PGC Logo
Porter GeoConsultancy Pty Ltd
 International Study Tours
     Tour photo albums
 Ore deposit database
 Conferences & publications
 Experience
PGC Publishing
 Our books  &  bookshop
     Iron oxide copper-gold series
     Super-porphyry series
     Porhyry & Hydrothermal Cu-Au
 Ore deposit literature
 
 Contact  
 What's new
 Site map
 FacebookLinkedin