Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 5 of 5
Full-Text Articles in Earth Sciences
Petrology And Geochemistry Of Evolved Achondrites: Planetesimal Mantles And Crusts, Zoltan Vaci
Petrology And Geochemistry Of Evolved Achondrites: Planetesimal Mantles And Crusts, Zoltan Vaci
Earth and Planetary Sciences ETDs
Melting and differentiation are fundamental to early solar system evolution on planetary bodies that accreted enough material to heat up radioactively or through impacts and breach their solidi. Partially and fully melted material is present in the meteorite record in the form of primitive achondrites and achondrites, which are fragments of planetesimals that underwent heating events in the first few million years of solar system history. Although the vast majority of this material is mafic or ultramafic, new evolved samples, recovered in the last few decades, are pushing the petrologic and geochemical boundaries of planetesimal melting, differentiation, and crust formation. …
Microstructural And Microchemical Studies Of Fluid–Chondrule Interactions In A Pristine Cr Carbonaceous Chondrite And Apatite In Martian Nakhlites, Marina Martínez
Microstructural And Microchemical Studies Of Fluid–Chondrule Interactions In A Pristine Cr Carbonaceous Chondrite And Apatite In Martian Nakhlites, Marina Martínez
Earth and Planetary Sciences ETDs
PROJECT 1: Chondrites are the most primitive objects in the solar system, aggregates of the material that formed in the solar protoplanetary disk during the first 1-5 million years of its formation. However, petrographic observations indicate that most chondrites have been modified by secondary processes, including aqueous alteration, thermal metamorphism, and shock. Fortunately, a few chondrites largely escaped these processes and are considered pristine, such as the CR carbonaceous chondrite Queen Alexandra Range (QUE) 99177. QUE 99177 is an excellent sample for deciphering information about the reactions that took place between unaltered anhydrous solar nebular components and water under highly …
Insights Into Fluid-Rock Interactions On The Cv3 Carbonaceous Chondrite Asteroid: The Complex Record In The Allende-Like Cv3 Chondrite, Nwa 2364., Jessica Marie Johnson
Insights Into Fluid-Rock Interactions On The Cv3 Carbonaceous Chondrite Asteroid: The Complex Record In The Allende-Like Cv3 Chondrite, Nwa 2364., Jessica Marie Johnson
Earth and Planetary Sciences ETDs
The two subgroups of the CV3 chondrites, oxidized and reduced, contain primitive solar system materials that provide many insights into early solar system processes. Both subgroups record significant evidence of secondary alteration that has modified their primary characteristics. In this work, we have studied the petrography, mineralogy, and oxygen isotopic composition of the NWA 2364 CV3OxA chondrite and a large lithic inclusion using SEM, electron microprobe, FIB/TEM, and laser fluorination oxygen isotope analyses in order to characterize their alteration histories in detail. The NWA 2364 host and lithic inclusion consist of chondrules, Calcium-Aluminum-rich Inclusions (CAIs), and fine-grained matrix. In …
Magmatic Hydrothermal Alteration And Secondary Post-Shock Features In Martian Olivine-Phyric Basalt Northwest Africa 10416; Petrology And Geochemistry Of Primitive Achondrite Northwest Africa 11042, Zoltan Vaci
Earth and Planetary Sciences ETDs
The Martian olivine-phyric basalt Northwest Africa (NWA) 10416 contains large olivine xenocrysts whose cores have been stained brown by hydrothermal alteration and whose rims are composed of pristine olivine overgrowths. Microanalysis of these olivine cores reveals various degrees of amorphization, some of which have been overprinted by terrestrial weathering, evident as part of a weathering rind along the exposed surface of the meteorite. Studies of a completely unweathered terrestrial analogue basalt from southern Colorado reveal similar features and indicate that both basalts were altered in a supersolidus magma chamber setting. The alteration features in NWA 10416 thus imply the presence …
Cl In The Early Solar System, Jeffrey Williams
Cl In The Early Solar System, Jeffrey Williams
Earth and Planetary Sciences ETDs
The early solar nebula is thought to have been a turbulent disk of dust and gas. An unknown mechanism caused the disk to collapse, such as a nearby super nova. This collapse led to high temperatures and high particle densities at the mid-plane of the disk. An unknown mechanism caused the temperature in local area to become hot enough to cause some material to melt –creating the first igneous material of the solar system. These melt spherules, called chondrules, cooled and accreted together with dust and ice to form larger bodies called chondrites. Once the chondritic bodies were of sufficient …