A chemostratigraphic method to determine the end of impact-related sedimentation at marine-target impact craters (Chesapeake Bay, Lockne, Tvären)

摘要: Abstract– To better understand the impact cratering process and its environmental consequences at local to global scale, it is important know when in geological record of an crater impact-related processes cease. In many instances, this occurs with end early modification, leaving obvious sedimentological boundary between impactites secular sediments. However, marine-target craters transition from collapse (i.e., water resurge) postimpact sedimentation can appear gradual. With a priori assumption that reworked target materials resurge deposits have different chemical composition sediments we use chemostratigraphy (δ13Ccarb, %Corg, major elements) Chesapeake Bay, Lockne, Tvaren craters, define boundary. We show these cases fairly rapid, does not necessarily coincide visual (e.g., grain size shift). Therefore, some cases, more precisely determined by chemostratigraphy, especially carbonate carbon isotope variations, rather than inspection. It also shown how confirm age were previously biostratigraphy; comparing trends established regional trends.