Weathering of ordinary chondrites from Oman: Correlation of weathering parameters with ¹⁴C terrestrial ages and a refined weathering scale

Abstract

We have investigated 128 14 C-dated ordinary chondrites from Oman for macroscopically visible weathering parameters, for thin section-based weathering degrees, and for chemical weathering parameters as analyzed with handheld X-ray fluorescence. These 128 14 C-dated meteorites show an abundance maximum of terrestrial age at 19.9 ka, with a mean of 21.0 ka and a pronounced lack of samples between 0 and 10 ka. The weathering degree is evaluated in thin section using a refined weathering scale based on the current W0 to W6 classification of Wlotzka (1993), with five newly included intermediate steps resulting in a total of nine (formerly six) steps. We find significant correlations between terrestrial ages and several macroscopic weathering parameters. The correlation of various chemical parameters including Sr and Ba with terrestrial age is not very pronounced. The microscopic weathering degree of metal and sulfides with newly added intermediate steps shows the best correlation with 14 C terrestrial ages, demonstrating the significance of the newly defined weathering steps. We demonstrate that the observed 14 C terrestrial age distribution can be modeled from the abundance of meteorites with different weathering degrees, allowing the evaluation of an age-frequency distribution for the whole meteorite population.

Meteorites from the Lut Desert (Iran)

“…High numbers of meteorites have been collected and studied from arid regions such as Atacama (Muñoz et al 2007;Gattacceca et al 2011;Hutzler et al 2016), Sahara (Bischoff and Geiger 1995;Schl€ uter et al 2002;Ouazaa et al 2009), Australian deserts (Bevan and Binns 1989;Bevan 1992;Benedix et al 1999), Arabian Peninsula (Al-Kathiri et al 2005;Gnos et al 2009;Hezel et al 2011;Hofmann et al 2018), central (Rubin and Read 1984;Merriam and Harbaugh 2007) and southwestern United States (Zolensky et al 1990;Rubin et al 2000;Kring et al 2001;Hutson et al 2013), and Xinjiang Province in China (Li et al 2017;Zeng et al 2018). Finding new meteorite dense collection areas (DCAs) is important for (1) discovering new types of meteorites (e.g., Bischoff 2001;Kent et al 2017;Pourkhorsandi et al 2017a), (2) providing more samples for statistical works on the meteorite flux (e.g., Bland et al 1996), (3) studying meteorite fall process by mapping strewnfields resulting from meteorite showers (e.g., Kring et al 2001;Gnos et al 2009), and (4) studying the alteration of extraterrestrial material in the terrestrial environment (Bland et al 2006;Saunier et al 2010;Uehara et al 2012;Zurfluh et al 2016;Pourkhorsandi et al 2017b) also in relation with paleoclimate (Bland et al 1998;Lee and Bland 2003;Pourkhorsandi et al 2017b).…”

Characteristics of the Sahara as a meteorite recovery surface

“…Systematic research applied by Hofmann et al (2003), Zurfluh et al (2016), Gattacceca et al (2011), andHutzler et al (2016) was very successful and allowed us to provide precise and high densities of meteorites in Oman and Chile. This led us to consider field missions in the desert of Morocco and Tunisia.…”

“…) and for Oman (Zurfluh et al. ). Concerning Morocco and Tunisia meteorites data are from this work (Table ).…”

“…In order to estimate the flux of meteorites to the Earth, many studies since 1995 have been undertaken to calculate the recovery density of meteorites in several hot deserts (Bland et al 1997), specifically the deserts of Sahara in Algeria (Bischoff and Geiger 1995), Australia , Libya (Schl€ uter et al 2002), Chile (Gattacceca et al 2011;Hutzler et al 2016), Oman (Hofmann et al 2009;Zurfluh et al 2016), United Arab Emirates (Hezel et al 2011), and Saudi Arabia (Hofmann et al 2018). We have summarized in Table 2 the various studies conducted in hot deserts, densities of meteorites recovered searching by car or on foot applying systematic or random methods.…”

Evaluation of meteorites as habitats for terrestrial microorganisms: Results from the Nullarbor Plain, Australia, a Mars analogue site

“…For petrological classification methods see Tait et al (2014); Van Schmus and Wood (1967), for shock classification see Stoffler et al (1991), and for weathering classification see Wlotzka (1993); Zurfluh et al (2016). Weathering grade in meteorites reflects terrestrial alteration of the original mineralogical composition since falling to Earth.…”