Seeking new paleotemperature proxies: Noble gases in evaporites

古气候记录为预测复杂气候变率的模式提供了必要的约束条件。然而，在地球温暖的干旱地区，古温度代用物很少。在环境温度下与大气平衡的地表水可能作为流体包裹体被困在矿物中，在这种条件下形成蒸发岩矿物。由于稀有气体在水中的溶解度与温度有关，该项目将研究蒸发岩在稀有气体古测温方面的潜力。活跃的盐场和现代岩盐提供了相对较好控制的露天环境，其中发生了岩盐降水。这些现代环境使我们能够研究短期温度波动如何反映在岩盐中流体包裹体的稀有气体温度中，从而校准代理记录。在本项目中，集合的研究时间将分析在已知地点和已知时期（即已知平均温度）形成的岩盐岩中流体包裹体的稀有气体浓度，以研究稀有气体温度与当地温度记录的关系。一个积极的结果将导致进一步的研究，建立新的古温度代理，并可能对气候模拟具有广泛的意义，通过提供更长时间内干旱地区的温度记录。更广泛的意义和重要性。能够预测地球上的气候变化可以说对地球上的人类至关重要，因为气候可以直接影响农业等重要活动。为了了解我们现代世界的气候，了解地球是很有帮助的。美国的气候贯穿了整个古代。通常我们通过地质记录了解过去的气候。然而，在地球上温暖干燥的地区，保存古代温度记录的地质材料很少，这使得我们很难确定这些地区的气候记录。该奖项为探索一种潜在的非常有用的方法提供了支持，即通过检测天然盐样本来检测这些地区的气候。当这些盐晶体形成时，液体和气体的微小气泡被困在里面。这些被困住的气泡被称为内含物。已经确定，水和卤水中化学惰性（惰性）气体的浓度取决于温度。因此，有可能通过测量包裹体的气体含量来确定古代地球的温度。为了确定这种方法是否真的有用，研究人员计划测量在已知条件下（主要是盐场）形成的盐晶体包裹体中的气体浓度。他们将观察这些现代盐晶体包裹体中的气体浓度得出的温度是否与当地的温度记录相匹配或对应。如果该方法被证明是一种成功的温度测量方法，将进一步研究该方法是否可以应用于古样品的古温度估计。因此，这样的工作可以为现代世界提供更好的气候预测。

Paleoclimate records provide essential constraints for models to predict complex climate variability. However, paleotemperature proxies are scarce in warm, arid regions of the Earth. Surface water equilibrated with the atmosphere at ambient temperatures may be trapped as fluid inclusions in minerals forming evaporite minerals under such conditions. As noble gas solubility in water is temperature-dependent, this project will examine the potential of evaporites for noble gas-based paleothermometry. Active salt farms and modern halite provide relatively well-controlled open-air environments in which halite precipitation occurs. These modern environments allow us to examine how short-term temperature fluctuations are reflected in the noble gas temperatures of fluid inclusions in halite, and thus to calibrate the proxy record. In this project, the assembled research time will analyze noble gas concentrations of fluid inclusions in halite that formed at known locations and during known periods of time (i.e. known average temperature) in order to investigate how the noble gas temperature relates to the local temperature record. A positive result will lead to further studies for establishing this new paleotemperature proxy and may have broad implications on climate modeling by providing temperature records for dry regions over extended time periods. Broader Significance and Importance.Being able to predict climate change on our planet is arguably of critical for humans on this planet, as climate can directly affect important activities such as agriculture. In order to understand climate in our modern world, it is very helpful to know about Earth?s climate throughout the ancient past. Usually we learn about past climates via geological records. However, geological materials that preserve records of ancient temperature are scarce in warm, dry regions of the Earth, which makes it difficult for us to determine the climate record for such areas.This award provides support to explore a potentially very useful method for examining climates of these regions by examining natural salt samples. When these salt crystals form, tiny bubbles of liquid and gas are trapped inside. These trapped bubbles are known as inclusions. It has been established that concentrations of chemically inert (noble) gases in water and brine depend upon temperature. Therefore, it is possible that the gas content of the inclusions could be measured to determine ancient Earth temperatures.To establish whether this method could really be useful, the investigators plan to measure the gas concentrations in inclusions of salt crystals formed under known conditions (mainly salt farms). They will see if the temperatures derived from gas concentrations in these modern salt crystal inclusions actually match or correspond to the local temperature records. If the method proves to be successful way to measure temperature, it will lead to further study on whether the method can be applied to obtain paleotemperature estimates from ancient samples. Consequently such work could enable better climate prediction for the modern world.