Cometary dust in Antarctic ice and snow: Past and present chondritic porous micrometeorites preserved on the Earth's surface

Sources of cosmic dust in the Earth's atmosphere

“…[], Yang and Ishiguro [], and Rowan‐Robinson and May [] (see section 1). It should be noted, as pointed out by Yang and Ishiguro [], that the analysis of Antarctic micrometeorites and cosmic dust particles collected in the stratosphere has found that less than 50% are “chondritic porous” particles, which are taken to be of cometary origin [ Noguchi et al ., ]. In contrast, the present study indicates that 63% of unmelted micrometeorites and cosmic spherules with diameters > 50 µm (the lower limit for measurements) should be cometary.…”

Novel Experimental Simulations of the Atmospheric Injection of Meteoric Metals

“…Unmelted IDPs (R > 50 m) collected in different studies consist of fine-grained aggregates and are similar to the matrix of carbonaceous chondrites, with a minor population of ordinary chondritic aggregates and anhydrous minerals (Dobric et al 2009;Taylor, et al 2012). Carbonaceous porous S-IDPs and MMs with R < 50 m have also been retrieved (Noguchi, et al 2015;Zolensky & Lindstrom 1992). In order to account for some of the properties of these populations, samples of the Allende (Krinov 1970) (CV3), Murchison (Fuchs, Olsen, & Jensen 1973) (CM2) and Chergach (Weisberg et al 2008) (H5) meteorites, and of terrestrial Mg-rich olivine and Na-rich and Ca-rich plagioclases were used in the MASI experiments (Table 1).…”

“…The current view is that IDPs are of mainly of cometary origin and related to carbonaceous chondrites (Noguchi et al 2015;Taylor, et al 2012), in contrast to terrestrial meteorites, most of which are 2…”

Cometary Isotopic Measurements

“…3) are thought to originate from comets. Such chondritic porous dust particles have also been identified from Antartic snow and ice collections (Noguchi et al 2015).…”