Variations in F and Cl contents in apatites from magnetite—apatite ores in northern chile, and their ore-genetic implications

Abstract

Magnetite-apatite deposits associated with the Atacama Fault Zone of northern Chile are interpreted here, on field criteria, as being the products either of hydrothermal fluids with a strong magmatic signature, or of latestage Fe-rich magmas mixed with an aqueous fluid. Even in the Chilean iron belt, apatite-rich magnetite deposits are a rarity. Variations in F-and C1-contents in apatites, strongly zoned with respect to halogens, are indicative of primary variations in fHF and fHCI in the hydrothermal fluids. Small variations in halogen fugacities in the aqueous fluid are capable of buffering large variations in halogen content within apatite crystals in equilibrium with that fluid. The recorded halogen zonation profiles are inconsistent with crystallization of the apatites simply from a volatile-rich, late-stage fractionation Fe-rich magma, or its derived magmatic vapour. It is more likely that they are the result of mineral-fluid buffering with a fluid that represents the mixing of a magmatically-derived aqueous fluid with a meteoric fluid that has variably scavenged Ca and C1 from within the country rocks. The source magma of the former is probably an Fe-P enriched acidic magma, derived by fractionation of primary calc-alkaline basic magmas.

Life Origination Hydrate Theory (LOH-Theory) and the Explanation of the Biological Diversification

“…Meanwhile, several localizations of sodium and potassium niters are known over the coastal continental heights of Chile, Bolivia, California, etc. (Frye 1982;Ericksen 1983) and localizations of apatite are available over Northern Chile, Brasil, and Mexico (Treloor and Colley 1996). All these deposits are rather extensive and their origin gives rise to a lot of talk.…”

Testing the apatite-magnetite geochronometer: U-Pb and 40Ar/39Ar geochronology of plutonic rocks, massive magnetite-apatite tabular bodies, and IOCG mineralization in Northern Chile

“…2). Its inferred shape, ascertained from the open pit, is defined by the intersection of W-E subvertical faults and N-S trending sets of dip slip faults (Treloar and Colley, 1996).…”

Multiple Stage Ore Formation in the Chadormalu Iron Deposit, Bafq Metallogenic Province, Central Iran: Evidence from BSE Imaging and Apatite EPMA and LA-ICP-MS U-Pb Geochronology

“…Similar textures have been reported from several other IOA type deposits in the Bafq district, including Se-Chahun (cf. [36]) and Gazestan [48], from Chilean IOA deposits [49], and from Yangtze Valley Mesozoic IOCG-IOA deposits, China [42]. Apatite also occurs as euhedral crystals enclosed in magnetite in the central parts of the veins (Figure 5b).…”