Matches in SemOpenAlex for { <https://semopenalex.org/work/W3209748793> ?p ?o ?g. }
- W3209748793 endingPage "1767" @default.
- W3209748793 startingPage "1751" @default.
- W3209748793 abstract "Abstract Studies of the new growth and re-distribution of Cu-rich phases in chondrites of different petrologic subtypes can potentially provide insights into post-accretionary parent-body processes. We present a systematic study of the distribution of Cu-rich phases and metallic Cu in Ornans-like carbonaceous chondrites (CO3) that underwent little aqueous alteration or shock (most with shock stages of S1) but exhibit a range of thermal metamorphism (subtype 3.0–3.7). A comparison to ordinary chondrites (OCs), which have undergone a larger range of shock levels, allows us to constrain the relative roles of radiogenic and shock heating in the origin of Cu distribution in chondrites. We found that the Cu content of Ni-rich metal and calculated bulk Cu content of CO3 chondrites (based on mass-balance calculations) show an increase from CO3.0 to CO3.2 chondrites. We speculate that some unidentified phases in the matrix account for a significant portion (nearly ~100 ppm) of the Cu budget in bulk samples of CO3.0 chondrites, while Ni-rich metal is the main Cu-carrier for CO3.2–3.7 chondrites. Within CO3.2–3.7 chondrites, Cu and Ni contents of Ni-rich metal are positively correlated, showing a systematic decrease from lower to higher subtype (~0.41 wt% Cu and ~45.0 wt% Ni in CO3.2 Kainsaz; ~0.28 wt% Cu and ~38.8 wt% Ni in CO3.7 Isna). Metallic Cu grains were found in every sample of CO3.2–3.7 chondrites, but not in any CO3.0–3.1 chondrites. Metallic Cu is: (1) present at metallic-Fe-Ni-pyrrhotite interfaces; (2) associated with fine irregular pyrrhotite grains in Ni-rich-metal-pyrrhotite nodules; (3) associated with fizzed pyrrhotite (fine-grained mixtures of irregularly shaped metal grains surrounded by pyrrhotite); (4) present at the edges of metallic Fe-Ni grains; and (5) present as isolated grains. In some metallic-Cu-bearing mineral assemblages, pyrrhotite has higher Cu concentrations than adjacent Ni-rich metal and shows a drop in Cu concentration at the interface between metallic Cu and Cu-rich pyrrhotite. This implies that the precipitation of metallic Cu grains could be related to the local Cu enrichment of pyrrhotite. We consider that radiogenic heating is mainly responsible for the formation of opaque phases in CO chondrites based on the relatively slow metallographic cooling rate (~0.1–5 °C/Ma), the increasing uniformity of Ni contents in Ni-rich metal with increasing CO subtype (44.3 ± 17.3 wt% in CO3.00 to 38.8 ± 3.4 wt% in CO3.7 chondrite), and the relatively narrow range of pyrrhotite metal/sulfur ratios (~0.976–0.999). Metal/sulfur ratios of pyrrhotite grains in most CO3.2–3.7 chondrites (mean = ~0.986–0.997; except Lancé) are slightly higher than those in CO3.0–3.1 chondrites (mean = ~0.981–0.987; except Y-81020), possibly indicative of a release and re-mobilization of sulfur during progressive heating as previously reported for type-3 chondrites. In this regard, we suggest most metallic Cu grains in CO3 chondrites may have precipitated from Cu-rich pyrrhotite due to sulfidation of Fe-Ni metal during parent-body thermal metamorphism. Locally, a few metallic Cu grains associated with fizzed pyrrhotite could have formed during transient shock-heating. Both thermal and shock metamorphism could be responsible for the formation of metallic Cu. Although the systematic decrease in the Ni contents of Ni-rich metal from subtype-3.2 to subtype-3.8 also occurs in OCs, the average Cu contents of Ni-rich metal grains are indistinguishable among type-3 OCs of different subtypes. The paucity of metallic Cu in weakly shocked type-3 OCs could be related to: (1) the relatively low-bulk Cu contents of OCs, and/or (2) the relatively rapid metallographic cooling rates at <500–600 °C (~1–10 °C/Ma for LL chondrites), possibly resulting from early disturbance of OC parent bodies. The intergrowth of metallic Cu and irregular pyrrhotite more commonly occurs in shocked type-4 to type-6 OCs than in CO3 chondrites. This could be due to S in type-4 to type-6 OCs being more mobilized due to shock heating than in unshocked CO3 chondrites. We predict that some other groups of carbonaceous chondrites (e.g., CI and CM) are less likely to produce metallic Cu due to the: (1) relatively low amount of metallic Fe-Ni; (2) relatively low parent-body temperatures of ~100–300 °C; (3) high mobility of Cu in solution for aqueously altered samples; and (4) the short heating duration for metamorphosed samples." @default.
- W3209748793 created "2021-11-08" @default.
- W3209748793 creator A5013973657 @default.
- W3209748793 creator A5034637836 @default.
- W3209748793 creator A5075159980 @default.
- W3209748793 date "2021-11-01" @default.
- W3209748793 modified "2023-10-16" @default.
- W3209748793 title "Formation of metallic-Cu-bearing mineral assemblages in type-3 ordinary and CO chondrites" @default.
- W3209748793 cites W1582517994 @default.
- W3209748793 cites W1637770996 @default.
- W3209748793 cites W1944675387 @default.
- W3209748793 cites W1964943224 @default.
- W3209748793 cites W1967876833 @default.
- W3209748793 cites W1970136411 @default.
- W3209748793 cites W1975205664 @default.
- W3209748793 cites W1979333292 @default.
- W3209748793 cites W1987234791 @default.
- W3209748793 cites W1992585640 @default.
- W3209748793 cites W2001235240 @default.
- W3209748793 cites W2007923596 @default.
- W3209748793 cites W2011740766 @default.
- W3209748793 cites W2012391153 @default.
- W3209748793 cites W2013998167 @default.
- W3209748793 cites W2016393403 @default.
- W3209748793 cites W2016669393 @default.
- W3209748793 cites W2017994269 @default.
- W3209748793 cites W2019143929 @default.
- W3209748793 cites W2019216558 @default.
- W3209748793 cites W2022621216 @default.
- W3209748793 cites W2023284063 @default.
- W3209748793 cites W2026108757 @default.
- W3209748793 cites W2028581564 @default.
- W3209748793 cites W2031509785 @default.
- W3209748793 cites W2033761225 @default.
- W3209748793 cites W2034819694 @default.
- W3209748793 cites W2037035072 @default.
- W3209748793 cites W2038248875 @default.
- W3209748793 cites W2039223788 @default.
- W3209748793 cites W2040279611 @default.
- W3209748793 cites W2040965184 @default.
- W3209748793 cites W2042094094 @default.
- W3209748793 cites W2044960835 @default.
- W3209748793 cites W2046173060 @default.
- W3209748793 cites W2048190638 @default.
- W3209748793 cites W2048781983 @default.
- W3209748793 cites W2051374087 @default.
- W3209748793 cites W2052495933 @default.
- W3209748793 cites W2054666458 @default.
- W3209748793 cites W2056371639 @default.
- W3209748793 cites W2058087180 @default.
- W3209748793 cites W2058616918 @default.
- W3209748793 cites W2060510592 @default.
- W3209748793 cites W2061335819 @default.
- W3209748793 cites W2063092091 @default.
- W3209748793 cites W2063902182 @default.
- W3209748793 cites W2064164839 @default.
- W3209748793 cites W2064840320 @default.
- W3209748793 cites W2064923150 @default.
- W3209748793 cites W2065064375 @default.
- W3209748793 cites W2065692046 @default.
- W3209748793 cites W2066037814 @default.
- W3209748793 cites W2073130108 @default.
- W3209748793 cites W2079116799 @default.
- W3209748793 cites W2081266067 @default.
- W3209748793 cites W2084566156 @default.
- W3209748793 cites W2090305591 @default.
- W3209748793 cites W2091537829 @default.
- W3209748793 cites W2093845085 @default.
- W3209748793 cites W2094580905 @default.
- W3209748793 cites W2096471541 @default.
- W3209748793 cites W2115724600 @default.
- W3209748793 cites W2116092675 @default.
- W3209748793 cites W2117079667 @default.
- W3209748793 cites W2119534587 @default.
- W3209748793 cites W2123537045 @default.
- W3209748793 cites W2125959382 @default.
- W3209748793 cites W2150227951 @default.
- W3209748793 cites W2153638970 @default.
- W3209748793 cites W2160134417 @default.
- W3209748793 cites W2166406131 @default.
- W3209748793 cites W2317215577 @default.
- W3209748793 cites W2409473120 @default.
- W3209748793 cites W2421898184 @default.
- W3209748793 cites W2554968006 @default.
- W3209748793 cites W2559788214 @default.
- W3209748793 cites W2750857236 @default.
- W3209748793 cites W2765341012 @default.
- W3209748793 cites W2932024972 @default.
- W3209748793 cites W2966304454 @default.
- W3209748793 cites W2969690591 @default.
- W3209748793 cites W2971781285 @default.
- W3209748793 cites W2997870472 @default.
- W3209748793 cites W3006420672 @default.
- W3209748793 cites W921771176 @default.
- W3209748793 doi "https://doi.org/10.2138/am-2021-7689" @default.
- W3209748793 hasPublicationYear "2021" @default.
- W3209748793 type Work @default.
- W3209748793 sameAs 3209748793 @default.