Thermochemical Models of Earth's Mantle Convection: New Insight from Fractionation and Outgassing Processes

地幔对流的热化学模型：来自分馏和放气过程的新见解

基本信息

批准号：
0126281
负责人：
Louise Kellogg
金额：
$ 24.89万
依托单位：
University of California-Davis
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2002
资助国家：
美国
起止时间：
2002-01-01 至 2005-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0126281&HistoricalAwards=false
关键词：
Thermochemical Models Earth Mantle Convection

项目摘要

Basalt geochemistry records information about mantle dynamics, indicating that there are at least five reservoirs in the mantle. However, the dynamical meaning of such reservoirs is ill-constrained. Efforts to reconcile the full range of types of observational data have recently given rise to several new geodynamic models that include layers of different composition in the mantle. The investigators will evaluate these and related models, by using numerical models of thermo-chemical convection in the mantle to determine the geochemical signatures predicted by different dynamical models. Simulations will include tracers to represent various chemical species. Partial melting processes at ridges are taken into account, yielding fractionation between oceanic crust and lithosphere, and outgassing into the atmosphere. These processes have not been included in previous large-scale, fully dynamic, convective models. The simulations keep track of ancient oceanic crust, and include intrinsic density variations between eclogite and peridotite, as well as inhomogeneous heat production rates. The investigators will address the ability of their different models to reproduce some of the features of basalt, and to be in agreement with geodynamical observations such as the heat flow. They will also test the sensitivity of the results to petrologic and geodynamic parameters.

玄武岩地球化学记录了有关地幔动力学的信息，表明地幔中至少存在五个储层。然而，此类储层的动力学意义并没有受到限制。最近，协调各种类型的观测数据的努力产生了几种新的地球动力学模型，其中包括地幔中不同成分的层。研究人员将通过使用地幔中热化学对流的数值模型来评估这些模型和相关模型，以确定不同动力学模型预测的地球化学特征。模拟将包括代表各种化学物质的示踪剂。考虑了海脊处的部分熔化过程，产生洋壳和岩石圈之间的分馏，并释放到大气中。这些过程尚未包含在以前的大规模、完全动态的对流模型中。这些模拟跟踪了古代洋壳，包括榴辉岩和橄榄岩之间的固有密度变化，以及不均匀的产热率。研究人员将解决不同模型重现玄武岩某些特征的能力，并与热流等地球动力学观测结果一致。他们还将测试结果对岩石学和地球动力学参数的敏感性。