Micrometeorites from Central Antarctic snow: The CONCORDIA collection

We recovered micrometeorites from surface snow layers near the French-Italian station CONCORDIA. The unique weather and isolation conditions of Dome C allowed us to recover micrometeorites that are much better preserved than those extracted from blue ice fields. We have identified a new population of friable fine-grained micrometeorites; the absence of such particles in previous collections can be explained by their destruction by mechanical processes. In contrast to previous collections of micrometeorites, the particles from CONCORDIA Collection are characterized by a high content of Fe-sulfides and an undepleted CI elemental abundance pattern of their fine-grained matrix. These features suggest that micrometeorites from Dome C snow have endured much lower alteration from terrestrial weathering, unlike the micrometeorites recovered from near the margin of the Antarctic ice sheet (Adelie Land). The CONCORDIA particles have well constrained terrestrial ages and, given the low Dome C precipitation rate, the central regions of Antarctica provide a unique opportunity to search for particles from historical meteor showers.