Katherine L. Maier, Lorna J. Strachan, Stephanie E. Tickle, A. Orpin, S. Nodder, Jamie Howarth
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引用次数: 0
Abstract
The 2016 Mw7.8 Kaikōura Earthquake in Aotearoa New Zealand provides an opportunity to test widely applied turbidite sedimentation models because it triggered a co-seismic turbidity current. The resultant Kaikōura event bed (KEB), interpreted as a turbidite, is sampled for approx. 1300-km down-flow along the depositional system. Sediment core lithologies, computed tomography (CT), and particle-size data are used to test event-bed thickness, silt content, facies distribution and stacking patterns against the foundations of the turbidite conceptual model of Bouma (1962). KEB thickness is variable to approx. 100 km down-flow distance and attains a maximum thickness at approx. 700 km down-flow distance before thinning distally, similar to the predicted bell-shaped proximal to distal trend. Silt content is high throughout the KEB from canyon to fan. The KEB is dominated by laminated Td facies and Te facies that evolve down-system from laminated, then graded, to homogenous muds. CT and granulometry data ar e key to differentiating subtle density and textural variations within fine-grained deposits and reveal that KEB Td and Te facies in the KEB that are often not preserved or readily observed in older deposits. The KEB highlights a fine-grained sedimentary system that contrasts with more widely studied sandy turbidite basins. In particular, the KEB example reveals that Td and Te facies are ubiquitous in this fine-grained, silt-rich system. A varied conceptual model developed from the KEB may be applicable to many modern deep-sea turbidite systems and crucial for understanding present-day particulate transport to the deep sea and interpreting evidence from the stratigraphic record.
期刊介绍:
The journal is broad and international in scope and welcomes contributions that further the fundamental understanding of sedimentary processes, the origin of sedimentary deposits, the workings of sedimentary systems, and the records of earth history contained within sedimentary rocks.