FN Archimer Export Format
PT J
TI Data report: reconnaissance of bulk sediment composition and clay mineral assemblages: inputs to the Hikurangi subduction system
BT 
AF Underwood, Michael B
AS 1:;
FF 1:;
C1 Department of Earth & Environmental Science, New Mexico Institute of Mining & Technology, Socorro NM 87801, USA
C2 DEPARTMENT OF EARTH & ENVIRONMENTAL SCIENCE, USA
TC 0
UR https://archimer.ifremer.fr/doc/00618/73033/72152.pdf
LA English
DT Article
CR MD 152 / MATACORE
BO Marion Dufresne
AB This report provides a reconnaissance-scale assessment of bulk mineralogy and clay mineral assemblages in sediments and sedimentary rocks that are entering the Hikurangi subduction zone, offshore North Island, New Zealand. Samples were obtained from three sites drilled during Leg 181 of the Ocean Drilling Program (Sites 1123, 1124, and 1125) and 38 piston/gravity cores that are distributed across the strike-length of the margin. Results from bulk-powder X-ray diffraction show large variations in normalized abundances of total clay minerals and calcite. The typical lithologies range from clay-rich hemipelagic mud (i.e., mixtures of terrigenous silt and clay with lesser amounts of biogenic carbonate) to calcareous mud, muddy calcareous ooze, and nearly pure nannofossil ooze. Basement highs (Chatham Rise and Hikurangi Plateau) are dominated by biocalcareous sediment, whereas most deposits in the trench (Hikurangi Trough and Hikurangi Channel) and on the insular trench slope are hemipelagic. Clay mineral assemblages (<2 µm) change markedly as a function of geographic position. Sediment entering the southwest side of the Hikurangi subduction system is enriched in detrital illite (>60 wt%) relative to chlorite, kaolinite, and smectite. Normalized proportions of detrital smectite increase significantly toward the northeast to reach values of 40–55 wt% offshore Hawkes Bay and across the transect area for Expeditions 372 and 375 of the International Ocean Discovery Program. 
PY 2020
PD MAR
SO Proceedings of the International Ocean Discovery Program
SN 2377-3189
PU International Ocean Discovery Program (IODP)
VL 372B/37
DI 10.14379/iodp.proc.372B375.203.2020
ID 73033
ER

EF