Aqueous alteration in Martian meteorite Northwest Africa 11013: an analysis of its extent and origin
(2025) In Dissertations in Geology at Lund University GEOL02 20251Department of Geology
- Abstract
- Nakhlites, which are clinopyroxene-rich cumulate rocks formed from basaltic magma around 1.3 billion years ago, frequently exhibit evidence of aqueous alteration. This study focuses on the extent and origin of aqueous alteration in the nakhlite Martian meteorite Northwest Africa (NWA) 11013, addressing four key research questions: the specific type of alteration, its connection to microstructures, its extent in olivine grains and its connection to Martian geological events. Utilising scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) and 2D-modelling with "Dragonfly 3D World," the mineralogical composition and the extent of alteration were analysed. Results indicate that NWA 11013 is primarily composed of... (More)
- Nakhlites, which are clinopyroxene-rich cumulate rocks formed from basaltic magma around 1.3 billion years ago, frequently exhibit evidence of aqueous alteration. This study focuses on the extent and origin of aqueous alteration in the nakhlite Martian meteorite Northwest Africa (NWA) 11013, addressing four key research questions: the specific type of alteration, its connection to microstructures, its extent in olivine grains and its connection to Martian geological events. Utilising scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) and 2D-modelling with "Dragonfly 3D World," the mineralogical composition and the extent of alteration were analysed. Results indicate that NWA 11013 is primarily composed of augite and feldspar-rich mesostasis, with Fe-rich olivine, Fe-Ti oxides and pyrite also present. Aqueous alteration, characterised by iron-rich silicate phases and calcium sulphates was predominantly observed along microstructures within olivine grains and in association with mesostasis, but not in contact with augite. Quantitative analysis revealed that the iddingsite alteration in olivine ranges from 5-35%, suggesting localised or limited fluid-rock interaction rather than widespread water saturation. This alteration appears to be structurally controlled by fractures which served as conduits for fluid infiltration. The observed alteration patterns, consistent with findings in other nakhlites, suggest a multi-stage process with potential shifts in environmental conditions on Mars, from reducing to oxidising. (Less)
- Abstract (Swedish)
- Nakhliter är kumulatbergarter som är rika på klinopyroxen och bildades från basaltisk magma för cirka 1,3 miljarder år sedan. De uppvisar vanligtvis tecken på vattenhaltig omvandling. Denna studie fokuserar på omfattningen och ursprunget av den vattenhaltiga omvandling i nakhlitiska marsmeteoriten Northwest Africa (NWA) 11013. Studien behandlar fyra centrala frågeställningar: omvandlingstypen, dess koppling till mikrostrukturer, dess utbredning i olivin, samt dess koppling till geologiska händelser på Mars. Genom att använda svepelektronmikroskopi (SEM) med energidispersiv röntgenspektroskopi (EDS) och 2D-modellering med "Dragonfly 3D World", analyserades den mineralogiska sammansättningen och omvandlingens utbredning. Resultaten visar att... (More)
- Nakhliter är kumulatbergarter som är rika på klinopyroxen och bildades från basaltisk magma för cirka 1,3 miljarder år sedan. De uppvisar vanligtvis tecken på vattenhaltig omvandling. Denna studie fokuserar på omfattningen och ursprunget av den vattenhaltiga omvandling i nakhlitiska marsmeteoriten Northwest Africa (NWA) 11013. Studien behandlar fyra centrala frågeställningar: omvandlingstypen, dess koppling till mikrostrukturer, dess utbredning i olivin, samt dess koppling till geologiska händelser på Mars. Genom att använda svepelektronmikroskopi (SEM) med energidispersiv röntgenspektroskopi (EDS) och 2D-modellering med "Dragonfly 3D World", analyserades den mineralogiska sammansättningen och omvandlingens utbredning. Resultaten visar att NWA 11013 huvudsakligen består av augit och en fältspatsrik mesostas, med förekomst av järnrik olivin, järn-titanoxider och pyrit. Den vattenhaltig omvandlingen, kännetecknad av järnrika silikatfaser och kalciumsulfater, observerades framför allt längs mikrostrukturer inom olivin och i samband med mesostasen, men inte i kontakt med augit. Kvantitativ analys visade att iddingsit-omvandlingen i olivin varierar mellan 5-35%, vilket tyder på en lokaliserad eller begränsad fluid-berginteraktion snarare än en utbredd vattenmättnad. Denna omvandling framstås vara strukturellt kontrollerad av sprickor som fungerade som kanaler för vätskeinfiltration. De olika observerade omvandlingar, som stämmer överens med fynd i andra nakhliter, tyder på en flerstegsprocess med potentiella förändringar i miljöförhållandena på Mars, från reducerande till oxiderande. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9202642
- author
- Popa, Alexandra LU
- supervisor
-
- Carl Alwmark LU
- organization
- course
- GEOL02 20251
- year
- 2025
- type
- M2 - Bachelor Degree
- subject
- keywords
- Nakhlite, aqueous alteration, Martian meteorites, olivine, microstructures
- publication/series
- Dissertations in Geology at Lund University
- report number
- 712
- language
- English
- id
- 9202642
- date added to LUP
- 2025-06-19 11:23:00
- date last changed
- 2025-06-19 11:23:00
@misc{9202642, abstract = {{Nakhlites, which are clinopyroxene-rich cumulate rocks formed from basaltic magma around 1.3 billion years ago, frequently exhibit evidence of aqueous alteration. This study focuses on the extent and origin of aqueous alteration in the nakhlite Martian meteorite Northwest Africa (NWA) 11013, addressing four key research questions: the specific type of alteration, its connection to microstructures, its extent in olivine grains and its connection to Martian geological events. Utilising scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) and 2D-modelling with "Dragonfly 3D World," the mineralogical composition and the extent of alteration were analysed. Results indicate that NWA 11013 is primarily composed of augite and feldspar-rich mesostasis, with Fe-rich olivine, Fe-Ti oxides and pyrite also present. Aqueous alteration, characterised by iron-rich silicate phases and calcium sulphates was predominantly observed along microstructures within olivine grains and in association with mesostasis, but not in contact with augite. Quantitative analysis revealed that the iddingsite alteration in olivine ranges from 5-35%, suggesting localised or limited fluid-rock interaction rather than widespread water saturation. This alteration appears to be structurally controlled by fractures which served as conduits for fluid infiltration. The observed alteration patterns, consistent with findings in other nakhlites, suggest a multi-stage process with potential shifts in environmental conditions on Mars, from reducing to oxidising.}}, author = {{Popa, Alexandra}}, language = {{eng}}, note = {{Student Paper}}, series = {{Dissertations in Geology at Lund University}}, title = {{Aqueous alteration in Martian meteorite Northwest Africa 11013: an analysis of its extent and origin}}, year = {{2025}}, }