Dark green spherules occur in the lower part of a turbidite in Section 603B-22-3, at the 70 cm level. In all probability these spherules originally consisted of massive glass, but now appear to have become completely altered into smectite. The presence of numerous microscopic fissures in the spherules probably mediated in the alteration process.Judging by the presence of similar spherules at the Cretaceous/Tertiary (K/T) boundary in DSDP Hole 390B, the green spherules are thought to represent diagenetically altered impact ejecta from one large or several smaller extraterrestrial objects at the end of the Cretaceous. The presence of anomalously high concentrations of Ni, Co, and As higher up in the turbidite are in agreement with an expected enrichment of these elements in the K/T boundary clay. However, precise Ir analyses are necessary in order to confirm this.
Analysis of planktonic foraminifers from Section 605-66-1 established the Cretaceous/Tertiary (K/T) boundary between 68 and 73 cm. Comparison with the detailed zonation established at El Kef, Tunisia, indicates that some of the section may be missing, probably because of drilling disturbance. The preservation of the planktonic foraminifers is generally good, particularly in the basal Paleocene section. However, extensive dissolution and the many broken specimens render quantitative estimates unreliable. There were no microtektite-like spherules to suggest a layer rich in extraterrestrial components, as have been found in most complete pelagic K/T boundary sections. The better preservation of Paleocene foraminiferal test in this core and in many other DSDP cores from other basins is probably due to a change in oceanic carbonate chemistry exactly at the K/T boundary. This may have been caused by a temporary and almost complete disappearance of carbonate-fixing organisms at the boundary.
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