Cretaceous foraminifers of Hole 530A, Leg 75, Deep Sea Drilling Project.

Abstract

Most of the 10cm3 samples from Hole 530A were barren of foraminifers. Most of the foraminiferal populations recovered were barren of planktonic specimens. Consequently, no correlation with established planktonic biozones was possible, and correlation with European stages was limited to Maestrichtian-Campanian, Santonian-Coniacian, ?lower Turonian, and Albian. Most of the benthic species were interpreted to be displaced - not reworked or redrilled cavings. Recognition of the displaced faunas helped in recognizing indigenous benthic faunas and in interpreting their paleodepth and provincial implications. Displaced faunas have temporal and paleogeographical value but not paleobathymetric value. The prevalent general properties at Site 530 of sparsity of specimens, rarity of planktonic specimens, low taxonomic diversity of indigenous benthic faunas, and etched, worn, and broken specimens, combined to indicate deposition well below the lysocline and near to, if not below, the carbonate compensation depth, or in the abyssal realm, during most of the Maestrichtian to Albian. The principal event of the sedimentary record is a medial Cretaceous lacuna, which includes most of the Turonian and Cenomanian and some of the Albian.-from Author