Mineralogical association and physical properties of sediments with palaeoclimatic implications (ODP Site 798B, Japan Sea); a comparative study from core and downhole measurements

Author(s): Lauer-Leredde, Christine; Pezard, Philippe A.; Robert, Christian; Dekeyser, Ivan
Author Affiliation(s): Primary:
ODP-NEB, Laboratoire de Mesures en Forage, Aix-en-Provence, France
Université d'Aix-Marseille II, France
Volume Title: Marine Geology
Source: Marine Geology, 150(1-4), p.73-98. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0025-3227 CODEN: MAGEA6
Note: In English
Summary: The aim of our approach is to provide a reliable and continuous mineralogical description derived from downhole logs and constrained by core measurements. This study focuses on a series of 742,000 year drilled during Ocean Drilling Program (ODP) Leg 128 at Site 798 on Oki Ridge (Japan Sea). A linear matrix algebraic procedure has been applied to eight logs (bulk density, neutron porosity, natural gamma-ray, uranium, thorium and potassium concentrations, photoelectric effect and electrical resistivity) to compute the proportions of opal, quartz, clay minerals (illite, chlorite, kaolinite, smectite) and water in the sediment. Similarly, a continuous cation exchange capacity (CEC) log is derived from the natural gamma-ray (CGR). A continuous intrinsic formation factor (FF), which depends on the structure of the pore space, is then computed from the CEC. The log-derived mineralogy and CEC are compared to laboratory analysis on samples. High-resolution mineralogy derived from the logs allows recognition of well-known episodes of climate evolution (development of glaciation and of aeolian processes at 2.5-2.3 Ma), as well as new insights into climate dynamics (occurrences of short, warm excursions and of unstable periods). Periodic oscillations in relation to orbital parameters are also deduced from log-derived mineralogy.
Year of Publication: 1998
Research Program: ODP Ocean Drilling Program
Key Words: 20 Geophysics, Applied; 24 Surficial Geology, Quaternary Geology; Cation exchange capacity; Cenozoic; Chlorite; Chlorite group; Clay mineralogy; Clay minerals; Cores; Density logging; Downhole methods; Electrical logging; Framework silicates; Illite; Japan Sea; Kaolinite; Leg 128; Marine sediments; Mathematical methods; Mineral composition; North Pacific; Northwest Pacific; ODP Site 798; Ocean Drilling Program; Opal; Pacific Ocean; Paleo-oceanography; Paleoclimatology; Physical properties; Pore water; Quartz; Quaternary; Radioactivity; Resistivity; Sediments; Sheet silicates; Silica minerals; Silicates; Smectite; Upper Quaternary; Well-logging; West Pacific
Coordinates: N370218 N370218 E1344759 E1344758
Record ID: 1998045933
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands