Temperature spectra of zircon crystallization in plutonic rocks

Abstract

The Ti-in-zircon thermometer is a potentially powerful new petrological tool, but conclusions drawn from such data are meaningful only to the extent that the underlying interpretational framework is sound. In the case of interpretation of detrital zircon crystallization temperature spectra, it has been assumed that comparisons can be made with potential host rocks based on calculated bulk zircon saturation thermometry. We show by calculation that most igneous rocks formed at high temperature (>750 °C) will yield Ti-in-zircon temperatures (T Ti zir) well above the wet granite solidus. This prediction is borne out by results from the Dala igneous complex, southeastern Tibet, which show a 300 °C range in T Ti zir beginning >100 °C above the calculated bulk zircon saturation temperature. Thus the dominant T Ti zir peak of >4 Ga zircons at ~680 °C implies a wet, anatectic magma source rather than an origin in intermediate and mafi c magmas. Given that preservation and analytical effects select against, or obscure recognition of, zircons formed at low temperature, the best explanation for the low Hadean T Ti zir peak is that it refl ects derivation from rocks that experienced prograde melting conditions under near-water-saturated conditions.

Paleoarchean Zircons from Quartzite of South Bundelkhand Supracrustal Complex:Origin and Implications for Crustal Evolution in Bundelkhand Craton, Central India

“…It is to be noted that a majority of the discordant zircons show much higher titanium-in-zircon temperatures compared to concordant ones (Table 1), which might be due to inputs from later hydrothermal fluids. The calculated crystallization temperatures from quartzite are similar to average crystallization temperatures of Early Archean detrital zircons, thereby pointing towards granitic parent magma 10,52,54 . This is also corroborated by the presence of zircon inclusions like quartz, muscovite, magnetite and monazite which are characteristic of granitoids (Figure 3).…”

A cirkon (U-Th)/He kormeghatározás módszertani alapjai és alkalmazása fiatal (<1 Ma) vulkánkitörések datálására

“…Adott leányizotóp ásványfüggésére jó példa az apa tit és a cirkon záródási hőmérséklet-tartománya közti eltérés az (UTh)/He rendszer esetében (3. ábra, A és B), míg ugyanazon ásványt vizsgálva az eltérő leányizotópok külön böző diffú -ziós viselkedését jól tükrözi a cirkon (U-Th)/He és U-Pb rendszer (3. ábra, B). Ez utóbbi sokkal magasabb hőmér -sékleten (> 900 °C; LEE et al 1997; 3. ábra, B) záró dik, mint az (U-Th)/He rendszer, és így jól alkalmazható a cirkon kristályosodási korának meghatározására, ami általában 900 °C alatt történik (HARRISON et al 2007).…”

Mecanismos eruptivos y procesos depositacionales del Grupo Choiyoi en el área de Las Caletas, Cordillera Frontal de San Juan, Argentina

“…Las condiciones mencionadas se acercan a las ideales para la aplicación del cálculo. Si bien la obtención de temperaturas de saturación de Zr a partir de la química de roca total puede tender a subvalorar significativamente la temperatura de cristalización de circón, tal como lo demuestran Harrison et al (2007) para granitoides, esta consideración no aplicaría al caso de estudio, ya que el circón fue una fase de cristalización temprana en las muestras consideradas. Además, los resultados del modelo de saturación de Zr aplicados en riolitas han sido sugeridos por Barrie (1995) como razonablemente coincidentes con los de geotermómetros más tradicionales, y han sido validados por Boehnke et al (2013) para temperaturas bajas >700°C.…”