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Extraterrestrial Cause for the Cretaceous-Tertiary Extinction
Platinum metals are depleted in the earth's crust relative to their cosmic abundance; concentrations of these elements in deep-sea sediments may thus indicate influxes of extraterrestrial material.… Expand
Tektite-bearing, deep-water clastic unit at the Cretaceous-Tertiary boundary in northeastern Mexico.
The hypothesis of Cretaceous-Tertiary (K-T) boundary impact on Yucatán, Mexico, predicts that nearby sites should show evidence of proximal impact ejecta and disturbance by giant waves. An outcrop… Expand
Iridium Anomalies of Late Eocene Age at Massignano (Italy), and ODP Site 689B (Maud Rise, Antarctic)
Iridium anomalies of Late Eocene age are here reported in sequences from northern Italy and Weddell Sea, Antarctic. We have analyzed 270 samples of marly limestones from the Eocene/Oligocene boundary… Expand
Spherule beds 3.47-3.24 billion years old in the Barberton Greenstone Belt, South Africa: a record of large meteorite impacts and their influence on early crustal and biological evolution.
Four layers, S1-S4, containing sand-sized spherical particles formed as a result of large meteorite impacts, occur in 3.47-3.24 Ga rocks of the Barberton Greenstone Belt, South Africa. Ir levels in… Expand
Basaltic explosive volcanism, but no comet impact, at the Paleocene-Eocene boundary: high-resolution chemical and isotopic records from Egypt, Spain and Denmark
- B. Schmitz, B. Peucker-Ehrenbrink, C. Heilmann-Clausen, G. Åberg, F. Asaro, C. Lee
- 30 August 2004
In the search for a triggering mechanism for the Paleocene-Eocene (P-E) boundary event, 55 Ma, centimeter-resolution chemical (e.g., Ir, Os, Pt) and isotope (e.g., (OS)-O-187/Os-188, He-3/He-4,… Expand
High-resolution iridium, δ13C, δ18O, foraminifera and nannofossil profiles across the latest Paleocene benthic extinction event at Zumaya, Spain
In the expanded upper Paleocene-lower Eocene section (~ 30 m of Zone P5 sediments) at Zumaya, northern Spain, the highest occurrence of many late Paleocene deep-sea benthic foraminifera species (~40%… Expand
Proximal impact deposits at the Cretaceous-Tertiary boundary in the Gulf of Mexico: a restudy of DSDP Leg 77 Sites 536 and 540.
Restudy of Deep Sea Drilling Project Sites 536 and 540 in the southeast Gulf of Mexico gives evidence for a giant wave at Cretaceous-Tertiary boundary time. Five units are recognized: (1) Cenomanian… Expand
The origin of the white beds below the Cretaceous-Tertiary boundary in the Gubbio section, Italy
Abstract Immediately below the Cretaceous-Tertiary (K-T) boundary clay layer in Umbrian pelagic limestone sections is a 0.5 m thick interval of white limestone beds. Geochemical and rock magnetic… Expand
Geological and Geochemical Record of 3400-Million-Year-Old Terrestrial Meteorite Impacts
Beds of sand-sized spherules in the 3400-million-year-old Fig Tree Group, Barberton Greenstone belt, South Africa, formed by the fall of quenched liquid silicate droplets into a range of shallow-to… Expand
Spheroids at the Cretaceous-Tertiary boundary are altered impact droplets of basaltic composition
Sand-size spheroids of K-feldspar in the Cretaceous-Tertiary (C-T) boundary clay at Caravaca, southern Spain, were interpreted by Smit and Klaver as having solidified from a melt resulting from the… Expand