Siderophile-element anomalies in CK carbonaceous chondrites: Implications for parent-body aqueous alteration and terrestrial weathering of sulfides

2006 ◽  
Vol 70 (15) ◽  
pp. 4019-4037 ◽  
Author(s):  
Heinz Huber ◽  
Alan E. Rubin ◽  
Gregory W. Kallemeyn ◽  
John T. Wasson
Keyword(s):  
Parent Body ◽  
Carbonaceous Chondrites ◽  
Aqueous Alteration

scholarly journals Exogenous copper sulfide in returned asteroid Itokawa regolith grains are likely relicts of prior impacting body

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Katherine D. Burgess ◽  
Rhonda M. Stroud
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Temperature ◽  
Copper Sulfide ◽  
Parent Body ◽  
Carbonaceous Chondrites ◽  
Aqueous Alteration ◽  
Thermal Alteration ◽  
Transmission Electron ◽  
Rubble Pile

AbstractSamples from asteroid 25143 Itokawa returned by the Hayabusa mission have been identified as LL4-6 ordinary chondrite materials and have shown it to be a rubble pile that aggregated after break-up of a parent body. Here we investigate particle RB-CV-0038 from the Itokawa regolith using scanning and transmission electron microscopy and energy dispersive spectroscopy. We identify a cubanite-chalcopyrite-troilite-pyrrhotite assemblage, the phases and structure of which are indicative of low-temperature, aqueous alteration. Cubanite is stable only at temperatures below around 250 °C and has thus far only been identified in CI carbonaceous chondrites and the comet 81P/Wild2 sample suite. Chalcopyrite is also very rare in the meteorite record and is found mostly in R chondrites and some CK chondrites. Because the Itokawa parent body experienced significant thermal alteration with little evidence of low-temperature equilibration or aqueous alteration, we propose that the assemblage we identify is most likely exogenous and represents a component of an impacting body.

scholarly journals Constraints on the ice composition of carbonaceous chondrites from their magnetic mineralogy

2021 ◽  
Author(s):  
Sanjana Sridhar ◽  
James Bryson ◽  
Ashley King ◽  
Richard Harrison
Keyword(s):  
Size Range ◽  
Parent Body ◽  
Carbonaceous Chondrites ◽  
Magnetic Mineralogy ◽  
Aqueous Alteration ◽  
First Order ◽  
Direct Replacement ◽  
History Of ◽  
Bulk Chemical ◽  
Weathering Effects

Carbonaceous chondrites experienced varying degrees of aqueous alteration on their parent asteroids, which influenced their mineralogies, textures, and bulk chemical and isotopic compositions. Although this alteration was a crucial event in the history of these meteorites, their various alteration pathways are not well understood. One phase that formed during this alteration was magnetite, and its morphology and abundance vary between and within chondrite groups, providing a means of investigating chondrite aqueous alteration. We measured bulk magnetic properties and first-order reversal curve (FORC) diagrams of CM, CI, CO, and ungrouped C2 chondrites to identify the morphology and size range of magnetite present in these meteorites. We identify two predominant pathways of aqueous alteration among these meteorites that can be distinguished by the resultant morphology of magnetite. In WIS 91600, Tagish Lake, and CI chondrites, magnetite forms predominantly from Fe-sulfides as framboids and stacked plaquettes. In CM and CO chondrites, <0.1 μm single-domain (SD) magnetite and 0.1–5 μm vortex (V) state magnetite formed predominantly via the direct replacement of metal and Fe-sulfides. After ruling out differences in temperature, water:rock ratios, terrestrial weathering effects, and starting mineralogy, we hypothesise that the primary factor controlling the pathway of aqueous alteration was the composition of the ice accreted into each chondrite group’s parent body. Nebula condensation sequences predict that the most feasible method of appreciably evolving ice concentrations was the condensation of ammonia, which will have formed a more alkaline hydrous fluid upon melting, leading to fundamentally different conditions that may have caused the formation of different magnetite morphologies. As such, we suggest that WIS 91600, Tagish Lake, and the CI chondrites accreted past the ammonia ice line, supporting a more distal or younger accretion of their parent asteroids.

scholarly journals Chemical, isotopic and amino acid composition of Mukundpura CM2.0 (CM1) chondrite: Evidence of parent body aqueous alteration

2019 ◽  
Vol 10 (2) ◽  
pp. 495-504 ◽  
Author(s):  
N.G. Rudraswami ◽  
A.K. Naik ◽  
R.P. Tripathi ◽  
N. Bhandari ◽  
S.G. Karapurkar ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Parent Body ◽  
Aqueous Alteration
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