Two major transects were drilled across the northeastern Australian margin during Leg 133. The southern transect, consisting of Sites 812 through 818 (and 826), extends from the northern edge of Marion Plateau north to the southern edge of Queensland Plateau. Hemipelagic and pelagic sediments were recovered at all sites from the Holocene back to the upper Miocene sections. Calcareous nannofossils are a major constituent of these sediments. Nearly all of the low-latitude nannofossil biohorizons can be identified in the Pliocene and Pleistocene, which makes it possible to construct a reasonably accurate biochronology for each site. Sites 813 and 814 are similar in sedimentation rate and succession of biohorizons, and both have a hiatus (nondeposition) that straddles the Miocene/Pliocene boundary; much of the lower Pliocene is missing. Site 812 is also similar to the last two, but its biostratigraphic resolution is reduced because of poorer preservation in critical intervals. Sites 815 and 816 are broadly similar in that both have excellent biostratigraphic resolution in the Pleistocene and uppermost Pliocene intervals, even though the sedimentation rate for the two is different. Both sites have an expanded mid-Pliocene section. At Site 815 the expanded Pliocene section has been identified as a contourite; however, there is no evidence in the nannofossils for significant redeposition. Site 815 also has exceptionally good biostratigraphic resolution into the upper Miocene section. The ranges of Amaurolithus tricorniculatus and Amaurolithus amplificus were clearly identified at this site, although the lack of a magnetostratigraphy prevents assigning precise ages to them. Sites 817 and 818 also are similar, although Site 818 is more expanded. Both sites have a hiatus at the Pliocene/Pleistocene boundary.

Supplement to: Gartner, Stefan; Wei, Wuchang; Shyu, Jih-Ping (1993): Neogene calcareous nannofossil biostratigraphy at sites 812 through 818, northeastern Australian Margin. In: McKenzie, JA; Davies, PJ; Palmer-Julson, A; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 133, 3-18