Bolivian tin belt

The Bolivian tin belt (Spanish: Cinturón estanifero boliviano, provincia estannifera boliviana[1]) is a mineral-rich region in the Cordillera Oriental of Bolivia.

Peraluminous magmas in turn results from the partial melting (anatexis) of metasedimentary rock and gneiss in the continental crust.

[1] Peraluminous magmas are rare in the Andes but more common in collisional orogens such the Himalayas.

From this it is inferred that the Andean orogeny in Bolivia should have features in common with collisional orogens.

The tectonic mechanism makes the invocation of a long-lived "tin anomaly" beneath the Cordillera Oriental unnecessary.