Estimating Influence of Crystallizing Latent Heat on Cooling‐Crystallizing Process of a Granitic Melt and Its Geological Implications

Abstract

Based on the theory of thermal conductivity, in this paper we derived a formula to estimate the prolongation period ( d t~) of cooling-crystallization process of a granitic melt caused by latent heat of crystallization as follows:where TM is initial temperature of the granite melt, TC crystallization temperature of the granite melt, C p specific heat, dtd cooling period of a granite melt from its initial temperature ( T~I ) to its crystallization temperature (Tc), QL latent heat of the granite melt.The cooling period of the melt for the Fanshan granodiorite from its initial temperature (900°C) to crystallization temperature (600°C) could be estimated -210,000 years if latent heat was not considered. Calculation for the Fanshan melt using the above formula yields a At,, value of -190,000 years, which implies that the actual cooling period within the temperature range of 900"-600"C should be 400,000 years. This demonstrates that the latent heat produced from crystallization of the granitic melt is a key factor influencing the cooling-crystallization process of a granitic melt, prolongating the period of crystallization and resulting in the large emplacement-crystallization time difference (ECTD) in granite batholith.

High heat production of the Late Mesozoic Luanchuan granites from East Qinling Orogen, China: Implications for petrogenesis and mineral exploration

“…This might be correlated with the high heat production rate of the Nannihu pluton (Figure 5). Usually, high heat production rate of granites can slowly release a large amount of heat, which prolongs the crystallization process of granite and promotes the migration rate of ore‐forming fluids and materials, further forming the word‐class Mo‐W polymetallic Nannihu deposit (Liu et al, 2023; Mao et al, 2011; Zhang et al, 2008).…”

“…Previous studies reported zircon U-Pb ages (closure temperature more than 900 C) of the Luanchuan granitoids with major age peaks at $147 Ma and $110 Ma, which are all interpreted as the crystallization ages of these granitoids (Xue et al, 2018;Yang et al, 2019) Nannihu deposit (Liu et al, 2023;Mao et al, 2011;Zhang et al, 2008). Han et al (2015), He (2015), Li et al (2012), Meng et al (2012), Qi (2014), Qian et al (2022), Tang et al (2021), Wang et al (2019), Xue (2017), Xue et al (2018), Yang, Wang, et al (2012), Yang, Li, and Chen (2012) Yang et al (2019), Zhang (2014), Zhang (2015), Zhang, Cao, et al (2018).…”