Bass Metals Ltd. (ASX:BSM) is an emerging producer of industrial mineral concentrates, approaching the key strategic milestone of profitable production at its flagship asset; the operating Graphmada Large Flake Graphite Mine in eastern Madagascar.


Madagascar: the geological setting and mineral prospectivity

Madagascar is part of the Mozambique Belt and has a diverse and complex geological setting that resulted from the continental collision between east and west Gondwana.

The eastern two-thirds of the island is dominated by Precambrian (to Archean) rocks that are divided into a series of major tectonic units, some of which are separated by lithospheric-scale shear zones. The major tectonic units are as follows:

  • Anosyan Block
  • Antananarivo Block
  • Antongil Block
  • Bekily Block
  • Bemarivo Belt
  • Betroka Block
  • Betsimisaraka Suture
  • Itremo Sheet
  • Tranomaro Block
  • Tsaratanana Sheet
  • Vohibory Block


The Precambrian rocks are dominated by quartzo-feldspathic gneisses, with a variable but lesser amount of metasedimentary, metavolcanic and metaplutonic rocks. In places, the eastern two-thirds of the island also includes Cretaceous through to Neogene basalts, dolerites and rhyolites.

The western third of the island consists of Phanerozoic (Upper Palaeozoic to recent) sedimentary and volcanic rocks that were deposited in two large basins (the Morondava and Mahajanga basins).

Madagascar contains a diversity of mineral commodities, including aggregates, aluminium, beryllium, chromium, coal, cobalt, copper, gas, gemstones (including emerald, ruby and sapphire), gold, graphite, iron, limestone, nickel, niobium, petroleum, platinum, rare earth elements, titanium and uranium.

(Supplied by Vato Consulting).