CLAYS BEYOND EARTH

摘要

Even the most casual observer will recognize that rocks transform to clay minerals over time on Earth, and clay minerals have played a particularly important role in the geologic evolution of our planet as well as the evolution of human civilization. Clay minerals, however, have also played an important role elsewhere in our Solar System, and they provide some of the best evidence of aqueous processes during time periods not accessible in Earth's rock record. The wealth of new data acquired using a variety of remote sensing techniques on planetary missions, coupled with detailed laboratory studies of meteorites, have increased awareness of this fact over the past several decades. The recent renewed interest in clay minerals formed beyond Earth led to a session on new developments in the study of extraterrestrial clay minerals during the 14th International Clay Conference in Castellaneta Marina, Italy, in 2009, and this issue of Clays and Clay Minerals presents several papers that resulted from that session.