Investigation of a new palaeothermometer: High precision isotope ratio measurement of multi-substituted isotopic molecules in carbonates

我们打算开发一种新的可行的和潜在的非常强大的技术，用于测量许多不同的碳酸钙沉积物，如石笋，凝灰岩，软体动物壳和珊瑚，在过去几十万年的不同时间形成的温度。这将有可能提供大量关于全球范围和长期气候变化性质的信息。重要的是，许多这类地质沉积物可以通过测量它们所含的少量铀和钍来非常精确地确定年代，而且由于可以使用非常小的样品（大约一毫克）进行温度测量，因此应该有可能获得具有非常高的时间分辨率（可能是十年或更少）的温度记录。为了实现这个目标，我们将使用定制的质谱仪，这种仪器能够测量岩石中碳酸钙分子质量的微小差异。这是一个技术上具有挑战性的项目，需要进行大量的实验和校准，然后才能常规使用，而这些技术方面正是该项目的重点。当这项技术完善后，除了研究过去的气候外，还可能有许多其他的地质、矿物和热液应用。

We intend to develop a newly viable and potentially very powerful technique for measuring the temperature at which many different calcium carbonate deposits, such as stalagmites, tufas, mollusc shells and corals, have been formed at various times over the past few hundred thousand years. Potentially this will provide a vast amount of information about the nature of climate change on a global scale and over long time periods. Importantly, many of these types of geological deposits can be very precisely dated by measuring the small amounts of uranium and thorium they contain, and because very small samples (about a milligram) can be used for temperature measurements, it should be possible to obtain temperature records with very high time resolution (probably decadal or less). To achieve the goal we shall use a custom built mass spectrometer, an instrument that is capable of measuring very small differences in the masses of calcium carbonate molecules within the rocks. This is a technically challenging project that will require a lot of experimentation and calibration before it can be used routinely and it is these technical aspects that are the focus of this project. When perfected, this technique will probably have many other geological, mineralogical and hydrothermal applications in addition to investigating past climates.