5:15 PM - 6:45 PM
[MGI31-P06] New ReCoRD Program: The Japan Sea paleoceanography and paleoclimatology during the Miocene (ReC23-03)
Keywords:The Repository Core Re-Discovery Program (ReCoRD), The Japan Sea, The Miocene, ODP Leg 127, IODP Exp. 346, Kochi Core Center (KCC)
The Repository Core Re-Discovery Program (ReCoRD) is new program started in 2023. In the ReCoRD, repository cores stored at Kochi Core Center (KCC) are reanalyzed by the ReCoRD research team, which is similar to science parties of drilling expeditions.
The third ReCoRD project, ReC23-03 “The Japan Sea paleoceanography and paleoclimatology during the Miocene” is accepted and scheduled in this year (https://j-desc.org/en/record/). In this project, we focus on understanding the oceanic environment changes in the warmer-than-today world, which is important for addressing future global warming. We especially focus on reconstructing short time scale oceanographic changes of the Japan Sea during the warm Miocene period. To understand oceanographic condition properly, comparison of sediments deposited at different water depth at the same time is necessary.
We use the Miocene Japan Sea sediments recovered at Sites 794, 795, 797 (drilled by ODP Leg 127 in 1989) and Sites U1425 and U1430 (drilled by IODP Exp. 346 in 2013). Since sediments taken by IODP Exp. 346 provide many scientific results, the Miocene oceanographic reconstruction is limited because comparison of different water depth is available only during short period (Tada et al., 2015; Irino et al., 2018; Kurokawa et al., 2019). During ODP Leg 127, many Miocene sediments were drilled from the deeper part of the Japan Sea (Tamaki, 1990). However, core gap is existed because of single hole drilling, and high-resolution (less than orbital scale) oceanographic reconstruction has not been conducted enough.
Therefore, in this project, our objective is to reconstruct millennial-scale, three dimensional oceanographic changes during the Miocene. We will especially focus on;
1) centennial to millennial scale oceanographic changes recorded in laminated sediments.
2) rapid warming event (~10.8Ma) and subsequent oceanographic condition, and possible relation with meteorite impact.
To achieve these scientific goals, the existing age models of cores are revised by revising biostratigraphy, tephra dating, and correlation of cores to different Sites utilizing chemical composition (XRF core scanner) and physical property (CT and logging data). Since non-destructive measurement will be conducted before sampling party in ReCoRD program, we also utilizing results of XRF core scanner and CT for sampling. For example, although calcareous microfossils are rarely observed in the Miocene Japan Sea sediments (Nomura, 1992; Tada et al., 2015), we select sediment intervals of high Ca contents utilizing XRF core scanner results for calcareous microfossil analysis.
ReC23-03 sample request is already open, and sampling party will be held in July. Since many kinds of analysis will be conducted after the sampling party under the collaboration as a ReC23-03 team, many outcomes are expected to raise from this ReCoRD program.
The third ReCoRD project, ReC23-03 “The Japan Sea paleoceanography and paleoclimatology during the Miocene” is accepted and scheduled in this year (https://j-desc.org/en/record/). In this project, we focus on understanding the oceanic environment changes in the warmer-than-today world, which is important for addressing future global warming. We especially focus on reconstructing short time scale oceanographic changes of the Japan Sea during the warm Miocene period. To understand oceanographic condition properly, comparison of sediments deposited at different water depth at the same time is necessary.
We use the Miocene Japan Sea sediments recovered at Sites 794, 795, 797 (drilled by ODP Leg 127 in 1989) and Sites U1425 and U1430 (drilled by IODP Exp. 346 in 2013). Since sediments taken by IODP Exp. 346 provide many scientific results, the Miocene oceanographic reconstruction is limited because comparison of different water depth is available only during short period (Tada et al., 2015; Irino et al., 2018; Kurokawa et al., 2019). During ODP Leg 127, many Miocene sediments were drilled from the deeper part of the Japan Sea (Tamaki, 1990). However, core gap is existed because of single hole drilling, and high-resolution (less than orbital scale) oceanographic reconstruction has not been conducted enough.
Therefore, in this project, our objective is to reconstruct millennial-scale, three dimensional oceanographic changes during the Miocene. We will especially focus on;
1) centennial to millennial scale oceanographic changes recorded in laminated sediments.
2) rapid warming event (~10.8Ma) and subsequent oceanographic condition, and possible relation with meteorite impact.
To achieve these scientific goals, the existing age models of cores are revised by revising biostratigraphy, tephra dating, and correlation of cores to different Sites utilizing chemical composition (XRF core scanner) and physical property (CT and logging data). Since non-destructive measurement will be conducted before sampling party in ReCoRD program, we also utilizing results of XRF core scanner and CT for sampling. For example, although calcareous microfossils are rarely observed in the Miocene Japan Sea sediments (Nomura, 1992; Tada et al., 2015), we select sediment intervals of high Ca contents utilizing XRF core scanner results for calcareous microfossil analysis.
ReC23-03 sample request is already open, and sampling party will be held in July. Since many kinds of analysis will be conducted after the sampling party under the collaboration as a ReC23-03 team, many outcomes are expected to raise from this ReCoRD program.