| Autor: |
Wu, Y.1,2 (AUTHOR) wuyh76@mail.sysu.edu.cn, Xiao, Z.1,3 (AUTHOR), Pan, L.4 (AUTHOR), Yan, P.1 (AUTHOR), Liao, S.3,5 (AUTHOR), Pan, Q.1 (AUTHOR), Li, S.6 (AUTHOR), Li, Y.3,5 (AUTHOR), Hsu, W.3,5 (AUTHOR) wbxu@pmo.ac.cn |
| Předmět: |
|
| Zdroj: |
Journal of Geophysical Research. Planets. Oct2024, Vol. 129 Issue 10, p1-16. 16p. |
| Abstrakt: |
Apatites record crucial information on the origin, composition, and chemical evolution of volatiles on terrestrial planets. As a martian intrusive rock, the gabbroic shergottite Northwest Africa (NWA) 13581 provides key information on the volatile evolution related to magmatic processes in the interior, shedding light on the intricate volatile circulation on Mars. The textural and chemical characteristics of the phosphates in NWA 13581 indicate a complex formation history involving fractional crystallization, degassing, and fluid interaction. Degassing of the NWA 13581 parent melt is capable of exsolving chlorine‐rich fluids, resulting in the formation of notably fluorine‐rich apatite with a high x‐site occupancy of fluorine up to 90%. The degassed/exsolved volatile‐rich fluids could subsequently continue to migrate and interact with surrounding magmatic suites, leading to highly heterogeneous compositions of active fluids. The crystallization of apatite is initiated by the interaction of fluids with merrillite at the late stage of the magmatic process, leading to the formation of phosphate intergrowths. Influenced by the composition and chemical evolution of volatiles in fluids and melts, apatite exhibits notable variability in chlorine compositions both within individual grains and among different grains. Moreover, the presence of magnetite associated with phosphate intergrowth highlights the transportation of metallic components in addition to volatiles from deep layers to shallower depths or to the surface of Mars. This process, which is observed in young shergottites, indicates the persistent presence of hydrothermal systems until recent geological periods, contributing to the generation and circulation of volatiles within the martian interior and on the surface. Plain Language Summary: Understanding the volatile composition of Mars is crucial for assessing its potential habitability. Apatite in the intrusive gabbroic martian meteorite Northwest Africa (NWA) 13581 provides valuable insights into the presence and evolution of halogens in martian magma. The textural and chemical features of phosphates suggest a complex formation process involving fractional crystallization, degassing and fluid interaction. In the case of cumulates such as NWA 13581, degassing could result in the exsolution of fluids, potentially serving as a brine source for the martian surface. Subsequent interaction with chlorine‐rich fluids further modifies the composition of apatite. Moreover, the presence of secondary magnetite indicates that elements like Fe can be extracted from the melt and transported by fluids, implying potential mining resources with a magmatic origin on Mars. The processes observed in NWA 13581 are likely common among different subtypes of shergottites. The diverse composition of apatite in shergottites that have undergone fluid interaction indicates localized and heterogeneous compositions of active fluids. The formation history preserved in NWA 13581 phosphate highlights the ongoing generation and circulation of volatiles on Mars, even in recent geological periods. Key Points: Phosphates in martian meteorite NWA 13581 support the magmatic origin of halogen fluids related to the magmatic process of shergottitesThe presence of magnetite indicates that hydrothermal fluids enable iron transportation and aggregation from the mantle to a shallower depthHydrothermal systems may have been common and active in recent geological periods, contributing to martian volatile generation and circulation [ABSTRACT FROM AUTHOR] |
| Databáze: |
GreenFILE |
| Externí odkaz: |
|
Plný text