상세정보
Export to Refworks부가기능
Geochemical Controls on the Fluid Evolution of Submarine and Subaerial Ore-forming Hydrothermal Systems
상세 프로파일
| 자료유형 | 학위논문 |
|---|---|
| 서명/저자사항 | Geochemical Controls on the Fluid Evolution of Submarine and Subaerial Ore-forming Hydrothermal Systems. |
| 개인저자 | Pierre, Samuel. |
| 단체저자명 | Colorado School of Mines. Geology and Geological Engineering. |
| 발행사항 | [S.l.]: Colorado School of Mines., 2019. |
| 발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
| 형태사항 | 109 p. |
| 기본자료 저록 | Dissertations Abstracts International 81-04B. Dissertation Abstract International |
| ISBN | 9781687984418 |
| 학위논문주기 | Thesis (Ph.D.)--Colorado School of Mines, 2019. |
| 일반주기 |
Source: Dissertations Abstracts International, Volume: 81-04, Section: B.
Advisor: Monecke, Thomas. |
| 이용제한사항 | This item must not be sold to any third party vendors. |
| 요약 | Seafloor hydrothermal venting influences the chemistry of the oceans and crust, is linked to the development of chemosynthetic life, and is associated to the formation of volcanic-hosted massive sulfide (VHMS) deposits. Ore-forming processes related to VHMS deposits are one of the oldest on Earth and account for more than half of the past global production of zinc and lead, 7 percent of the copper, 18 percent of the silver, and a significant amount of gold and other byproduct metals. In this thesis we explore the potential links between the variability of fluid compositions in submarine hydrothermal vents on the modern seafloor and the diversity of hydrothermal alteration mineralogy surrounding VHMS deposits in ancient volcanic terranes. Compiled data of natural vent fluid compositions from the neovolcanic zones of the global oceans, primary-secondary mineralogy occurring in active geothermal systems, and empirical knowledge on VHMS deposits are used to reconstruct the parameters controlling fluid evolution in ore-forming hydrothermal environments. Geochemical modeling using the Gibbs free energy minimization method is employed to evaluate chemical equilibria between fluids and minerals in these complex multicomponent systems.A case study on hydrothermal processes at mid-ocean ridges shows that an excellent agreement can be obtained between numerical simulations and natural vent fluid compositions found in such environment. The study shows that the vent chemistry is primarily controlled by fluid-rock interaction following seawater circulation in the oceanic crust and distinguishes the role of these processes from other mechanisms such as fluid phase separation. It is emphasized that the fluid to rock ratio plays an important role on the mechanisms of mass transfer, in addition to temperature and composition. The diversity of tectonic settings in which submarine hydrothermal systems are documented is then considered to investigate the possible role of crustal composition on the chemistry of hydrothermal fluids. Fluid-rock interaction simulations in peridotite-, basalt-, and rhyolite-hosted environments are compared to a global vent fluid data set to show that hydrothermal fluids retain systematic signatures of the petrogenetic environments they derive from. This work places quantitative major element and pH restrictions on the identity of these fluids. Due to the numerous similarities between submarine and subaerial hydrothermal systems, the thesis finally focuses on the differences of fluid-rock interaction processes responsible for hydrothermal alteration in VHMS and low-sulfidation epithermal deposits on land. Fundamental constraints related to the pH of fluids at hydrothermal conditions are linked to the contrasted alteration mineralogy developing around these deposits. |
| 일반주제명 | Geology. Geochemistry. |
| 언어 | 영어 |
| 바로가기 | 
: 이 자료의 원문은 한국교육학술정보원에서 제공합니다. |
