@article{9, author = {Norman MacLeod and Gerta Keller}, title = {Hiatus distributions and mass extinctions at the Cretaceous/Tertiary boundary}, abstract = {

Much disagreement over the interpretation of data bearing on various Cretaceous/Tertiary (K/T) extinction scenarios results from a failure to view these data within their appropriate stratigraphic context. Combined biostratigraphic and chronostratigraphic analyses of K/T boundary sequences have revealed systematic differences in patterns of sediment accumulation within continental-shelf and deep-sea depositional settings. Although virtually all deep-sea boundary sequences are marked by intervals of nondeposition or hiatus formation during the latest Cretaceous and earliest Tertiary, many continental shelf-slope sequences appear to be temporally complete over this same interval. This differential pattern of sediment accumulation can be related to the latest Maastrichtian-earliest Danian sea-level rise, during which deep-sea sediment- accumulation rates would be expected to drop as the locus of sediment deposition migrated across the continental shelf. Our data suggest that the abrupt shifts in carbon-isotope abundances, single-peak Ir anomalies, and apparently instantaneous mass extinctions of marine plankton{\textemdash}which are routinely reported from deep-sea K/T boundary sequences and used to support a causal relation between Late Cretaceous bolide impacts and K/T mass extinctions{\textemdash}may be artifacts of a temporally incomplete (or extremely condensed) deep-sea stratigraphic record.\  PDF

}, year = {1991}, journal = {Geology}, volume = {19}, pages = {497-501}, url = {http://geology.gsapubs.org/content/19/5/497.abstract}, doi = {10.1130/0091-7613(1991)019<0497:HDAMEA>2.3.CO;2}, language = {eng}, }