Diogenites are orthopyroxenites and harzburgites that are petrogenetically associated with basaltic magmatism linked to the earliest stages of asteroidal melting on the parent body for the howardite–eucrite–diogenite (HED) meteorites. There are several models proposed for their origin: (1) accumulation of orthopyroxene (OPX) + chromite (CHR) ± olivine (OL) during the crystallization of a magma ocean during the initial stages of asteroidal differentiation, (2) accumulation of OPX + CHR ± OL during the crystallization of compositionally distinct basaltic magmas emplaced into the crust of the HED parent body, and (3) the orthopyroxenites formed by the crystallization of basaltic magmas within the HED parent body crust, whereas the harzburgites represent the mantle of the HED parent body. Although OL and OPX experienced varying degrees of subsolidus reequilibration (1100–700 °C), their minor and trace element characteristics appear to partially preserve magmatic signatures that provide insights into distinguishing among different models for the origin of diogenites. The OPX exhibits a continuous and very systematic variation in incompatible elements such as Al, Ti, Zr, Y, and Yb. Polymict diogenites (i.e. Roda, EET 79002) can contain distinct lithologies with both different incompatible element characteristics and different model abundances of OL. There appears to be no relationship between the appearance and abundance of OL and the incompatible element characteristics of the OPX. The OL exhibits a range in Mg# and systematic variations Ni, Co, Ni/Co, and Mn. For examples, low Ni/Co appears to be closely associated with the harzburgites and Ni and Mn exhibit a negative correlation. Surprisingly, incompatible element concentrations in OPX are not negatively correlated to Ni concentrations in OL. The continuous nature of the minor and trace element characteristics of the OPX and OL is consistent with the all the diogenite lithologies forming through a single process such as crystallization within a magma ocean or a series of layered intrusions. Further, the range in incompatible element variability in the OPX, the Ni and Co systematics in the OL, and the association of distinctly different lithologies within polymict diogenites are most consistent with the diogenites representing lithologies from diverse layered intrusions. Alternatively, they may represent crystallization products of a magma ocean much more complex than has been thus far proposed (i.e. multiple MOs). There are some distinct differences between diogenites and the OL-rich achondrite QUE 93148 that was also analyzed during this study. These differences (such as Ni/Co in OL, estimated conditions of fO2) suggest that QUE 93148 is closely related to main-group pallasites rather than the parent bodies for the HED meteorites.

Petrogenetic Relationships Between Diogenites and Olivine Diogenites: Implications for Magmatism on the HED Parent Body

Northwest Africa (NWA) 4255 is a meteorite found in the region of Tindouf (southwestern Algeria), classified as brecciated olivine diogenite. Based on textural observations and orthopyroxene compositions, two different lithologies were determined: harzburgitic and orthopyroxenitic. The orthopyroxenitic lithology contains orthopyroxene (Mg no. 73.99–75.68) and spinel (Cr no. 83.09–85.11, Mg no. 15.57–22.45). On the other hand, the harzburgitic lithology contains orthopyroxene (Mg no. 74.54–77.14) and olivine (Mg no. 70.94–72.57). The iron metal and the sulfides (Troilites) of this sample are present in both lithologies and are low in Ni (Ni < 0.1 wt%). The Fe/Mn ratio of orthopyroxenes ranges from 22.28 to 32.64 and show a large overlap between both lithologies. Lowest ratios are unusual; they are below the defined field for diogenites and olivine diogenites. ∆17O values are − 0.234 ± 0.003 (1σ) and confirm that the NWA 4255 originated from 4Vesta. The results of this study show that there is a genetic linkage between the two lithologies of NWA 4255 and correspond to in situ crystallization processes. This olivine diogenite reflects transition between two major magmatic processes in 4Vesta. The magma ocean of 4Vesta crystallized at equilibrium, allowing the formation of a dunitic and harzburgitic mantle. This late lithology is linked to the peritectic reaction between the olivines formed and the evolved liquid. Our sample then reflects this crucial step of separating this mantle from the residual liquid. This melt evolving on the peritectic allowed the formation of the observed harzburgitic assemblage and then evolves out from the peritectic reaction to proceed to a fractional crystallization process involving the formation of orthopyroxenite.

/pdf/petrology-mineralogy-and-geochemistry-of-the-olivine-1ymx8nao4c.pdf

Petrology, mineralogy, and geochemistry of the olivine diogenite NWA 4255: new insights into the magmatic evolution of asteroid 4 Vesta

Seddiki, B. N. Moine, R.C. Greenwood, J. Y. Cottin and I.A. Franchi, Laboratoire GEOREN, Univ. Oran 2MBA-Oran, Algeria (ratibakared@yahoo.com); Université Clermont Auvergne, CNRS, IRD, OPGC, Laboratoire Magmas et Volcans, F-63000 Clermont-Ferrand, France; Planetary and Space Sciences, Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK; Laboratoire LGL-TPE UMR CNRS 5276 (CNRS, ENS, Université Lyon1, UJM-Saint-Etienne) F-42023, Saint-Etienne Cedex 02, France.

Northwest africa 14091: a new stannern-group eucrite from algeria

Northwest Africa 16273: 4Vesta’s mantle sampled during the giant impact

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Ratiba Kared

Author Tools

Chat about Author

Papers

Petrology, mineralogy, and geochemistry of the olivine diogenite NWA 4255: new insights into the magmatic evolution of asteroid 4 Vesta

Northwest africa 14091: a new stannern-group eucrite from algeria

Northwest Africa 16273: 4Vesta’s mantle sampled during the giant impact