Nonlinear processes in geochemical systems

在自然界中，非线性复杂系统经常被驱动远离平衡。生物当然是这样，但许多地球化学系统也是如此，其中化学反应发生在开放环境中。这些系统可能由确定性过程、随机强迫（代表与系统耦合的环境的随机性质）或两者驱动。使用分析和数值方法相结合，拟议的研究的目标是调查各种非平衡非线性地球化学系统，所有的都是由一个共同的线程：它们构成的表现形式的非线性反应输运现象在地球化学相关的设置。更具体地说，我将帮助回答这些问题：“是什么原因导致许多矿床表现出复杂的空间格局，使其化学成分沿沿着核到缘的剖面（振荡环带）或沿矿物集合体（周期性沉淀）发生变化？通过对这些模式的分析，我们可以了解这些矿床的成因条件吗？例如，我们可以开发古气候的情况下，解释存在的周期性沉淀带的黄铁矿在东地中海的沉积物？从航空照片上观察到的北方森林中形成的有趣的大型森林年轮图案的地球化学过程是什么？“火山系统提供了地球化学复杂系统的其他例子，这些系统富含远离平衡的非线性过程。我将有助于解决以下问题：“在岩浆系统中的气泡在剧烈喷发的发展中发挥了什么作用？我们能否用浮岩氧化作用作为估算火山羽流温度历史和冷却速率的代用指标（地质测速法）？"

In nature, nonlinear complex systems are often driven far from equilibrium. This is certainly true of living beings, but it is also the case for many geochemical systems, where chemical reactions occur in open environments. These systems may be driven by deterministic processes, stochastic forcing (representing the random nature of the environment coupled to the system), or both. Using a combination of analytical and numerical methods, the goal of the proposed research is to investigate a variety of non-equilibrium nonlinear geochemical systems that all are linked by a common thread: they constitute manifestations of non-linear reactive transport phenomena in geochemically relevant settings. More specifically, I will contribute to answer these questions: "What causes many mineral deposits to exhibit complex spatial patterns, whereby their chemical composition varies along a core-to-rim profile (oscillatory zoning) or across a mineral aggregate (periodic precipitation)? What can we learn about the genesis conditions of these deposits from the analysis of these patterns? For instance, can we develop paleo-climatic scenarios that explain the presence of periodic precipitation bands of pyrite in sediments of the Eastern Mediterranean? What are the geochemical processes leading to the formation of the intriguing large forest rings patterns, observed in the boreal forest from aerial photographs?" Volcanic systems provide other examples of geochemical complex systems rich in far-from-equilibrium non-linear processes. I will contribute to address the following questions:" What is the role played by gas bubbles in magmatic systems in the development of violent eruptions? Can we use pumice oxidation as a proxy for estimating the temperature history and cooling rate of a volcanic plume (geospeedometry)?"