Abstract

Introduction: The principal discrepance of the studies of asteroids and meteorites was the diference between spectra of the most common asteroid S and Q type and the most common meteorites ordinary chondrites (OC)[1]. Spectroscopic observations in visible wave- lenghts of near-Earth asteroids (NEAs) show that more than 50% of them correspond to the S- and Q- types [2].Recent results indicated that the surface materials of this asteroids was char- acterized by ordinary chondrites-like spectra[3]. Some small NEA’s showed Q-type spectra which are similar to those of the ordinary chon- drite, with low degree of space weathering [3]. Otherwise S-type asteroids spectra was modi- fied by space weathering to the present-day darker and redder spectra [3]. Researchers also reported that a spectral transition could occur between S-type and Q-type asteroids [3][4]. The results of Hayabusa mission, the first studie in a asteroids sample, show a direct link be- tween OC and S-type asteroids. The Itokawa’s surface correspond to OC, in particular LL chondrites and provide evidence of space weathering rims and grain abrasion [5]. The OC represent the 87% of the total meteor- ites in the world and the 89% of the meteorites in Chile (Table 1). The systematic search we have been carrying out over the last 10 years has increased the number of official chilean meteorites to 886 until the end of 2016 [6]. This accumulation of meteorites in certain de- sert surfaces has only been possible due to the hyperaridity regime sostained during at least 1,5 My. We will present the chilean collection (ta- ble 1), at present formed by 89% of ordinary chondrites, 7% irons, 2% of carbonaceous chondrites, 1% achondrites and 1% of stony- irons. The 89% of OC correspond to 806 mete- orites from wich ~55% are H-type, ~39 % are L-type and ~6% are LL-type, most of them availables for the scientific community for stud- ies. The low porcent of LL-chondrites in the world and chilean collections could be explaind by the fact that contain less FeNi metal and therefore difficult to detect through magnetic susceptibility or for the hyphotesis that holds the flux of meteorites changed qualitatively over the time, hypothesis supported by several authors [7]. This maintains open the discussion on the parental body of this type of chondrites.