(Table 1) Summary statistics of taxa in samples of ODP Hole 181-1123B, supplement to: Scott, George H; Hall, Ian R (2004): Planktonic foraminiferal evidence on late Pliocene-Quaternary near surface water masses at ODP Site 1123B, northern Chatham Rise, east of New Zealand. Marine Geology, 205(1-4), 127-145

• Main Authors: Scott, George H, Hall, Ian R
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2004
• Subjects: Species; Mean, statistical; Standard deviation; Minimum; Maximum; Drilling/drill rig; Counting >150 µm fraction; Calculated; Leg181; Joides Resolution; Ocean Drilling Program ODP; New Zealand; Neogloboquadrina pachyderma; Planktonic foraminifera
• Online Access: https://dx.doi.org/10.1594/pangaea.734647; https://doi.pangaea.de/10.1594/PANGAEA.734647

Planktonic foraminifera are used to identify late Pliocene-Quaternary near surface water masses on the northeastern flank of Chatham Rise by comparison with faunas in core-tops east of New Zealand. In an overview study, distance measures, ordinations, and discriminant analysis are applied to 32 faunas from Site 1123B to identify similar faunas among 35 core-tops between 35 and 61°S east of New Zealand. Many Site 1123B faunas in the 2.72 myr interval sampled compare with those in core-tops on the northern side of Chatham Rise from a similar latitude, and are identified as transitional zone assemblages now associated with the subtropical gyre. This result is consistent with studies of late Quaternary planktonic foraminifera from this region and suggests that, typically, the Subtropical Front was locked to Chatham Rise through glacial and interglacial periods, at least back to the late Pliocene. However, a fauna at ca. 1.17 Ma compares with subpolar assemblages in core-tops between 44 and 48°S and identifies cooler surface water. Expectedly, closer sampling may reveal additional periods when southern water moved over the northeastern flank of Chatham Rise. Although the dominance of Globorotalia inflata, a species typical of the southern margin of subtropical gyres, is a principal feature of Site 1123B faunas, in a minority it is replaced as the most abundant species by dextral populations of Neogloboquadrina pachyderma, particularly about the time of the middle Pleistocene transition. Close analogues of these variant transitional assemblages are not present in core-tops about Chatham Rise but sediment trap and coretop data from other regions suggest that they identify high fertility in the mixed layer associated with upwelling or mixing of water masses. The proportion of sinistrally coiled Neogloboquadrina pachyderma rises to ca. 0.6 between ca. 2.45 and 2.57 Ma, soon after the intensification of Northern Hemisphere glaciation. Although the coiling data indicate subantarctic near surface water, the species remains rare. As the faunas retain their transitional zone character, only minor entrainment of subantarctic water may have occurred. : Globorotalia inflata includes 19 specimens of Globorotalia puncticuloides and Globorotalia puncticulata? from 4 samples below 8H-5-100. Globorotalia oceanica (no peripheral keel) from 10H-2-100-10H-7-5 is included in Globorotalia crassaformis. Globigerinita glutinata includes Globigerinita juvenilis. Globigerina falconensis includes tentative identifications. Neogloboquadrina dutertrei s.l. comprises forms intermediate between Neogloboquadrina dutertrei and Neogloboquadrina pachyderma; no typical specimens of the former were found.