Radiocarbon dating, microscopy of paleobotanical samples, and analytical pyrolysis of fluvial sediments in Arlington Canyon on Santa Rosa Island by another group found no evidence of lonsdaleite or impact-induced fires. Research published in 2012 has shown that the so-called "black mats" are easily explained by typical earth processes in wetland environments.
Radiocarbon dating, microscopic examination of ancient plant remains, and thermal analysis of riverbank deposits in Arlington Canyon on Santa Rosa Island by another team discovered no proof of lonsdaleite or fire-induced damage. Research published in 2012 revealed that the "black mats" can be easily attributed to natural processes occurring in wetland ecosystems.