deletions | additions       diff --git a/untitled.tex b/untitled.tex  index a5772e8..18308fd 100644  --- a/untitled.tex  +++ b/untitled.tex 
...
\subsection{Temperature estimation using $\Delta_{47}$}  Using the clumped isotope composition of carbonate minerals as a geothermometer is a relatively immature young and developing  technique. Of particular importance Critical to it's successful application  is the lack of agreement on the a robust  calibration between the deviation from a stochastic distribution of the isotopes $\Delta_{47}$  and temperature. At present there exist several different calibrations (references). These are illustrated in Figure 4.  There exists is  a large number range in both the temperature sensitivity (gradient) and offset  of calibrations the different calibrations. Here we simply point out that for this study we have used the temperature calibration determined at UEA using biogenic carbonates and travertine samples collected from sites with well characterized temperatures:  \[{\Delta _{47}} = \frac{{0.0389 \times {{10}^6}}}{{{T^2}}} + 0.2139\]  where T is in Kelvins. As  with varying degrees most previous studies the calibration has been made over a restricted temperature range (0-56$^{\circ}$C that lies below the temperature range  ofsensitivity. Moreover,  most samples collected in this study.  of these calibrations have been made over a restricted range of temperatures based on the collection of biogenic carbonates from environments with known temperature (e.g. references). More recently calibrations have become available for inorganically precipitated calcites. However these have not served to resolve the origin of the differences. What is clear from these studies is that differences between calibrations are laboratory dependent. i.e. measurements of unknown samples when converted to a temperature only make geological sense when the local Δ47 - T calibration is used. If another laboratories calibration is used then unrealistic temperatures are often estimated. This points to significant methodological issues associated with sample preparation and mass spectrometry that have yet to be resolved. We don’t discuss these here. For this study we have used the UEA determined calibration to translate Δ47 values for carbonates into temperature.    (6)  This calibration is based on (i) biogenic carbonates (bivalves and foraminifera) collected from environments with known environmental temperature; (ii) natural inorganic calcites from travertines precipitated at spring heads with known temperature, and (iii) experimental inorganic carbonates precipitated or recrystallised at known temperatures. A single calibration is consistent across the temperature range covered by the calibration from 0 - 600°C. We note that within measurement error this calibration is indistinguishable with the theoretical line of Guo et al. (2009).