1 Borate Deposits of Turkey and Argentina; A Summary and Geological Comparison

Abstract: Turkey has the largest borate reserves in the world and Argentina is in third place. Both countries have calcium and sodium borate deposits where colemanite, ulexite and borax are the principal minerals. We present here a comparison of the main borate deposits interlayered in continental Miocene volcaniclastic rocks of the Anatolian plateau (Turkey) and those of the Puna high plateau (Argentina). The main borate deposits of Turkey are at Emet, Bigadiç, Kestelek and K›rka. Emet is in the western part of the Kütahya province. In Emet, a sedimentary lacustrine sequence rich in tuffaceous materials hosts the colemanite section. There are limestones and marl layers at the base and top of the borate section. Arsenic minerals (realgar and orpiment) are very abundant and spatially related to the borates, indicating a common genetic origin. The principal borate mineral is colemanite with minor ulexite, hydroboracite, meyerhofferite, and rarer species such as veatchite-A, tunellite, teruggite and cahnite. Colemanite occurs as nodules of different sizes, agglomerated in thick beds. Bigadiç has borates interbedded with tuffs, clay and limestone layers. The borate minerals are formed in two distinct zones, lower and upper, separated by thick tuff beds. Colemanite and ulexite predominate in both borate zones. Other borates include howlite, probertite and hydroboracite in the lower zone, and inyoite, meyerhofferite, pandermite (priceite), terschite, hydroboracite, howlite, tunellite and rivadavite in the upper borate zone