Early-concept grant for exploratory research (EAGER) proposal: Accessing the potential of clumped isotope thermometry to constrain temperatures in the Arctic during the Pliocene

本研究的具体目标是确定是否碳酸盐？凝聚同位素？温度测量可以应用于软体动物，以准确和精确地重建北极的温度。 以前的工作表明，碳酸盐矿物中发生多个稀有同位素替代，也称为？结块？重同位素相互成键的过程是温度依赖的。该温度代理也独立于水的del-18 O和溶解无机碳的del-13 C。PI和co-PI及其合作者对生物沉淀方解石和文石的初步研究表明，13 C-18 O键丰度的测量应该允许人们对矿物形成的温度进行相对无干扰的测定。虽然这个新的代理看起来很有希望，但在低温下（即，低于15 ℃）。因此，这一代用指标在北极气候重建中的效用尚不清楚。 该项目将确定该技术应用于在北极温度下生长的生物样品时的准确性和精确度，从而确定该技术评估极地地区古海洋温度的能力，温度的仪器记录最多只能追溯到几百年前。 为了了解局部或全球温度的自然变化，我们需要更长的记录。 为了建立这样的记录，我们依赖于温度的代理测量。 使用这种替代指标需要作出假设，而且往往会对估计的温度造成较大的误差。 该项目将确定一个新的代用品在极地地区的效用。

The specific goal of this research is to identify whether carbonate ?clumped isotope? thermometry can be applied to mollusks to accurately and precisely reconstruct temperatures in the Arctic. Previous work has shown that the occurrence of multiple rare isotope substitutions in carbonate minerals, also referred to as the ?clumping? of heavy isotopes into bonds with each other, is temperature dependent. This temperature proxy is also independent of the del-18O of water and the del-13C of dissolved inorganic carbon. Initial studies of biologically-precipitated calcite and aragonite by the PI and co-PI and collaborators indicate that the measurements of 13C-18O bond abundance should allow one to make a relatively assumption-free determination of the temperature at which a mineral formed. Although this new proxy looks promising, calibration of the clumped isotope thermometer at low temperatures (i.e., below 15°C) is limited. Therefore the utility of this proxy for climate reconstructions in the Arctic is unclear. This project will determine the accuracy and precision of the technique when applied to biological samples grown at Arctic temperatures and, consequently, the ability of this technique to assess paleo ocean temperatures in polar regions.The instrumental record of temperature only goes back in time a few hundred years, at most. In order to understand the natural variability of temperature, either locally or globally, we require much longer records. To develop such records, we rely on proxy measurements for temperature. Use of such proxies requires assumptions and often imposes large error bars on the estimated temperature. This project will determine the usefulness of a new proxy in the polar regions.