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\subsection{Temperature}  The data for the temperature at which calcite precipitated at Dirtlow Rake are the first measurements made for the southern Pennines using the clumped isotope technique. They show that temperatures varied during vein growth between lower and upper limits of 30 to 100$^{\circ}$C. As seen in Figure 5 these temperature variations are episodic, representing periods during which the temperature evolved followed by sharp breaks in the temperature trends.  It is relevantt relevant  to ask if these temperatures are robust and representative of the likely  hydrothermal fluid temperatures.We find a temperature range of 40$^{\circ}$C to 100$^{\circ}$C.  The most direct comparison that we  can be made make  is with fluid inclusion homogenization temperatures. Several fluid inclusion studies Hollis and Walkden (2002) report a mean temperature of 154$^{\circ}$C with a large range of between 100 and 200$^{\circ}$C for inclusions in zone 4 calcites sampled from the northern margin of the Derbyshire platform. Higher maximum temperatures and a greater temperature range  have been completed, largely using fluorite but also with reported by Kendrick et al. (2002) for fluorites from Hucklow Edge,  a limited number mineralized vein within 10km  of Dirtlow Rake (T_{max}=240$^{\circ}$C, range = 90-240$^{\circ}$C). These authors exclude temperatures as high as 300$^{\circ}$C suggesting the  data points are compromised by stretching of and fluid loss from the inclusions. All these temperatures are significantly higher than the temperature range we report for DLR7 and higher than any temperatures we have recorded elsewhere in the Peak District (unpublished data). The high maxima and large range of temperatures reported by Hollis and Walkden (2002) and Kendrick et al. (2002) are hard to reconcile with the clumped isotope data. They are also hard to understand in relation to current basin evolution models for the Edale Gulf (Colman, 1989, Walkden and Williams, 1991) which suggest maximum depths of burial of five to six km. To achieve temperatures of 240$^{\circ}$C would require geothermal gradients of more than 40$^{\circ}$C.km^{-1}. A possible explanation for the discrepancy between clumped isotope and fluid inclusion homogenization temperatures is that the inclusions are gas rich. Gas rich inclusions have been reported from carbonate phases from MVT districts \citep{Jones_1992}. Homogenization of gas rich inclusions will occur at higher temperatures than  for calcite. a pure water inclusion.  In contrast the clumpoed isotope data is in good agreement with several other fluid inclusion studies.  Overall there is wide variation in the reported homogenization temperatures ranging from 60$^{\circ}$C to greater than 240$^{\circ}$C. Our temperature estimates fall towards the lower end of this range and are consistent with the homogenization temperatures reported for type 2 (62$^{\circ}$-82$^{\circ}$C), type 3 (64.9$^{\circ}$-98.9$^{\circ}$C), type 4 (63.4$^{\circ}$-106$^{\circ}$C) and type 5 (66.3$^{\circ}$-68.3$^{\circ}$C) inclusions in fluorite reported by Atkinson (1983). The type 1 inclusions reported on by Atkinson (1983) have higher homogenization temperatures of 119.5$^{\circ}$ - 157$^{\circ}$C. These are higher than the maximum temperatures we have observed for this part of the orefield. A difficulty in making a comparison is that the different types of inclusions are thought to relate to different stages in the mineral paragenesis and may not directly relate to the calcite veins at Dirtlow Rake. The vein calcite at Dirtlow Rake is from zone 4 of the paragenetic sequence outlined by Walkden and xxxx. Hollis and Walkden have published limited fluid inclusion data for calcites from this zone.