Oxygen isotopes in cosmic spherules and the composition of the near Earth interplanetary dust complex

The Extraterrestrial Dust Flux: Size Distribution and Mass Contribution Estimates Inferred From the Transantarctic Mountains (TAM) Micrometeorite Collection

“…Data from these experiments therefore predict that different size fractions of the micrometeorite flux will preferentially sample different parent bodies. This has since been confirmed by empirical study (Cordier & Folco, ; Suavet et al, ; van Ginneken et al, ), and further suggests that we should expect at least one major inflection point in the size distribution of micrometeorite collections between 100 and 300 μm.…”

“…Meanwhile petrological investigation of micrometeorites tends to conclude that asteroidal sources, from fine-grained hydrated CM, CR, and CI-like materials, are dominant (Kurat et al, 1994;Suttle et al, 2019;Taylor et al, 2012;van Ginneken et al, 2012). Finally, O-isotope data collated from multiple studies conclude that 20% of the dust flux is sourced from anhydrous inner solar system asteroids (ordinary chondrites and basaltic HED materials), while 60% are derived from primitive carbonaceous chondrite materials, including both CM/CO/CR/CI chondrites and cometary objects (Cordier & Folco, 2014;Goderis et al, 2019;Suavet et al, 2010;van Ginneken et al, 2017). The problems differentiating primitive asteroids and cometary material may reflect a possible continuum between these objects (Gounelle, 2011).…”

Cosmic spherules from Widerøefjellet, Sør Rondane Mountains (East Antarctica)

“…Micrometeorites (MMs), dust particles within the size range of 10 lm-2 mm (Rubin and Grossman, 2010), dominate the 40,000 ± 20,000 metric tons of extraterrestrial matter accreting to Earth every year (Love and Brownlee, 1993). Due to different production mechanisms in and transportation pathways from their source regions, these microscopic particles sample parent bodies different from those of meteorites (e.g., Fredriksson and Martin, 1963;Ganapathy et al, 1978;Engrand and Maurette, 1998;Flynn et al, 2009;Gounelle et al, 2009;Dartois et al, 2013;Cordier and Folco, 2014;Rubin, 2018). Generally recovered from deep-sea sediments, seasonal lakes in Greenland, ice and snow in Greenland and Antarctica, Antarctic moraines, continental sands and soils, and more recently also urban environments (e.g., Brownlee et al, 1979;Blanchard et al, 1980;Koeberl and Hagen, 1989;Hagen et al, 1989;Engrand and Maurette, 1998;Taylor and Lever, 2001;Genge et al, 2016Genge et al, , 2017Rudraswami et al, 2016;van Ginneken et al, 2017), MMs have also been found concentrated in high-altitude sedimentary traps, i.e., a pits, fissures and cracks of glacially eroded surfaces, in the Transantarctic Mountains (TAM) (e.g., Rochette et al, 2008;Suavet et al, 2009).…”

“…In this work, a new sedimentary MM collection from mount Widerøefjellet in the Sør Rondane Mountains (SRM) of Dronning Maud Land in eastern Antarctica is documented, and the physicochemical characteristics of the deposits and most obvious CSs larger than 200 lm are compared to those of the TAM and other MM collections. As CSs dominate the MM influx in the size fraction larger than 50 lm, constituting a representative subpopulation for the entire MM flux (e.g., Brownlee et al, 1997;Taylor et al, 2012;Cordier and Folco, 2014), a fraction of the largest CSs recovered from Widerøefjellet has been characterized for major (n = 49) and trace (n = 44) element concentrations, as well as for high-precision oxygen isotopic compositions (n = 28), after structural characterization by lCT. While the textures and chemical compositions of extraterrestrial particles are reprocessed by alteration during their terrestrial residence, this work focuses on confirming the primary nature of the MM precursor materials and refining the processes that affected these particles during atmospheric passage.…”

“…While the textures and chemical compositions of extraterrestrial particles are reprocessed by alteration during their terrestrial residence, this work focuses on confirming the primary nature of the MM precursor materials and refining the processes that affected these particles during atmospheric passage. While there is convincing evidence, based on elemental compositions and oxygen isotope ratio studies (e.g., Genge et al, 1997;Noguchi et al, 2002), that a large fraction of the MMs is related to carbonaceous chondrites of various clans and groups, the ratio of MMs related to ordinary as compared to carbonaceous chondrites and their distribution per size fraction, is currently based on only a limited number of analyses, especially for the larger size fractions (e.g., Steele, 1992;Kurat et al, 1994;Brownlee et al, 1997;Engrand and Maurette, 1998;Engrand et al, 2005;Gounelle et al, 2005;Genge et al, 2008;Suavet et al, 2010;Cordier et al, 2011aCordier et al, , 2011bTaylor et al, 2012;Rudraswami et al, 2012Rudraswami et al, , 2015aRudraswami et al, , 2015bRudraswami et al, , 2016van Ginneken et al, 2012van Ginneken et al, , 2017Imae et al, 2013;Cordier and Folco, 2014). The ratio of carbonaceous chondrite relative to ordinary chondrite material decreases as CS diameters increase, from a factor of 10 for small particles (<500 lm in diameter) to a factor of 0.3 for larger particles, indicating that the contribution of ordinary chondrite material to the composition of the micrometeoroid complex increases with MM size, with a possible continuum between meteorites and MMs (Cordier and Folco, 2014).…”