Thermo‐Hydro‐Chemical Simulation of Mid‐Ocean Ridge Hydrothermal Systems: Static 2D Models and Effects of Paleo‐Seawater Chemistry
Thermo‐Hydro‐Chemical Simulation of Mid‐Ocean Ridge Hydrothermal Systems: Static 2D Models and Effects of Paleo‐Seawater Chemistry
复制标题
大洋中脊热液系统的热氢化学模拟：静态二维模型和古海水化学的影响
DOI：
10.1029/2022gc010524
复制
发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Pester, Nicholas J.
中科院分区：
文献类型：
--
作者：
DePaolo, Donald J.;Sonnenthal, Eric L.;Pester, Nicholas J.
经过几十年的研究，人们已经对大洋中脊(MOR)热液系统的海底现象进行了描述，但考虑到热传递、水文学和地球化学之间的联系的数值模型发展缓慢。热-水-化学程序ToughReact可用于描述MOR系统中流体流动、热传递和流体-岩石化学相互作用的耦合效应。我们描述了具有矿物-流体化学反应的裂隙辉绿岩中稳态流动的二维模拟结果。基础加热和规定渗透率产生的最高温度为400°C。总流体流量和高裂缝流动速度与观测结果一致。流体化学、矿物学变化和~(87)Sr/~(86)Sr比值可以与观测结果相比较，以评估和校准模型。模拟高温压裂液的镁和硫酸接近于零，钙升高，87锶/86锶约为0.7040。对于简单的扩散模型，总改变量为10%-50%。硬石膏主要形成在上升流带底部附近，导致局部裂缝孔隙度大幅降低。一个校准的模型被用来预测在白垩纪(95 Ma)、早元古代(1,800 Ma)和太古宙(3,800 Ma)，当海水可能具有高Ca和Sr浓度、低pH、高温度和低Na、Mg和SO4时，蚀变洋壳的锶同位素和其他特征将如何不同。这些模拟被提供为最终可能需要社区更好地了解MOR热-水-化学系统在地球演化中的作用的长期努力的一个开始。
Decades of research have resulted in characterization of the ocean floor manifestations of mid‐ocean ridge (MOR) hydrothermal systems, yet numerical models accounting for the connections between heat transfer, hydrology and geochemistry have been slow to develop. The Thermo‐hydro‐chemical code ToughReact can be used to describe the coupled effects of fluid flow, heat transfer, and fluid‐rock chemical interactions that occur in MOR systems. We describe the results of 2‐dimensional simulations of steady state flow in fractured diabase with mineral‐fluid chemical reactions. Basal heating and specified permeability yield maximum temperature of 400°C. Total fluid flux and high fracture flow velocities are in accord with observations. Fluid chemistry, mineralogical changes and87Sr/86Sr ratios can be compared to observations to assess and calibrate models. Simulated high temperature fracture fluids have Mg and SO4near zero, elevated Ca and87Sr/86Sr of about 0.7040. Total alteration is 10%–50% for simple models of spreading. Anhydrite forms mainly near the base of the upwelling zone and results in substantial local fracture porosity reduction. A calibrated model is used to predict how Sr isotopes and other features of altered oceanic crust would be different in the Cretaceous (95 Ma) early Proterozoic (1,800 Ma) and Archean (3,800 Ma), when seawater may have had high Ca and Sr concentrations, lower pH, higher temperature, and lower Na, Mg, and SO4. The simulations are offered as a start on what ultimately may require a longer‐term community effort to better understand the role of MOR thermo‐hydro‐chemical systems in Earth evolution.
登录
查看更多内容
DOI：
--
发表时间：
2000
期刊：
影响因子：
--
作者：
A. Halliday
通讯作者：
A. Halliday
影响因子：
--
作者：
T. Bowers;H. Taylor
通讯作者：
T. Bowers;H. Taylor
影响因子：
3.7
作者：
A. Cherkaoui;W. Wilcock;R. Dunn;D. Toomey
通讯作者：
A. Cherkaoui;W. Wilcock;R. Dunn;D. Toomey
影响因子：
5
作者：
D. Syverson;D. Syverson;D. Syverson;Peter P. Scheuermann;J. Higgins;N. Pester;W. Seyfried
通讯作者：
D. Syverson;D. Syverson;D. Syverson;Peter P. Scheuermann;J. Higgins;N. Pester;W. Seyfried
“量化古代洋中脊海洋氧同位素的缓冲”的补充材料
影响因子：
--
作者：
Yoshiki Kanzaki
通讯作者：
Yoshiki Kanzaki