Core-seismic correlation and sequence stratigraphy at IODP Expedition 317 drillsites, Canterbury Basin, New Zealand

Author(s): Polat, Faik Ozcan
Source: 82p. Institution: University of Texas at Austin, Austin, TX, United States
Note: In English. 46 refs. Geologic map ; Master's thesis
Summary: High rates of Neogene sediment influx to the offshore Canterbury Basin resulted in preservation of a high-resolution record of seismically resolvable sequences (∼0.1-0.54 my periods). Subsequent sequence development was strongly influenced by submarine currents. This study focuses on correlating seismically interpreted sequence boundaries and sediment drifts architectures beneath the modern shelf and slope with sediment facies observed in cores from shelf Site U1351 and slope Site U1352 drilled by Integrated Ocean Drilling Program (IODP) Expedition 317. A traveltime-depth conversion was created using sonic and density logs and is compared with two previous traveltime-depth conversions for the sites. Eleven large elongate drifts were interpreted prior to drilling. Two new small-scale plastered slope drifts in the vicinity of the IODP sites, together with sediment waves drilled at Site U1352, have been interpreted as part of this study. Lithologic discontinuity surfaces and transitions together with associated sediment packages form the basis of identifying sequences and sequence boundaries in the cores. Contacts and facies were characterized using shipboard core descriptions, emphasizing grain-size contrasts and the natures of the lower and upper contacts of sediment packages. Lithologic surfaces in cores from sites U1351- (surfaces S1-S8) and U1352- (surfaces S1-S6) correlate with early Pleistocene to recent seismic sequence boundaries U12-U19 and U14-U19, respectively. The limited depths achieved by downhole logging, in particular sonic and density logs, together with poor recovery in the deeper section did not allow correlation of older lithologic surfaces. Slope Site U1352 experienced a complex interplay of along-strike and downslope depositional processes and cores provide information about the principal facies forming sediment waves. The general facies are fine-grained mud rich sediment interbedded decimeter-centimeter thick sand and sandy mud. Core evidence for current activity is reinforced at larger scale by seismic interpretations of sediment waves and drifts.
Year of Publication: 2012
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; 20 Geophysics, Applied; Bedding; Canterbury Basin; Cenozoic; Clastic rocks; Correlation; Depositional environment; Depth; Downhole methods; Drilling; Elastic waves; Expedition 317; Geologic map; Geologic maps; Geophysical methods; Geophysical surveys; IODP Site U1352; Integrated Ocean Drilling Program; Lithofacies; Maps; Mudstone; Neogene; Pacific Ocean; Planar bedding structures; Pleistocene; Quaternary; Sedimentary rocks; Sedimentary structures; Seismic methods; Seismic stratigraphy; Sequence stratigraphy; South Island; South Pacific; Southwest Pacific; Surveys; Tertiary; Traveltime; West Pacific
Coordinates: S445615 S445615 E1720122 E1720122
Record ID: 2013032328
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.