| Project/Area Number |
18540451
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Geology
|
|---|
| Research Institution | Shinshu University |
|---|
Principal Investigator |
HOYANAGI Koichi Shinshu University, Fac Science, Associate Professor (30202302)
|
|---|
| Project Period (FY) |
2006 – 2007
|
| Project Status |
Completed (Fiscal Year 2007)
|
| Budget Amount *help |
¥3,790,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥390,000)
Fiscal Year 2007: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2006: ¥2,100,000 (Direct Cost: ¥2,100,000)
|
|---|
| Keywords | Pliocene / Dainenii Formation / shelf / organic matter / climate change / submarine canyon / stable carbon isotope / diatom fossil / 大年寺層 / 金津層 / 環境変動 / テクトニクス / 陸棚の堆積作用 |
|---|
| Research Abstract |
Pliocene Dainenji Formation is distributed in the Pacific side of the Fukushima Prefecture. The Dainenji Formation is deposited on shelf environment and consists mainly of sandy siltstone and sandstone. It includes a number of volcanic ash layers, which serve as good key beds useful for precise correlation. Its depositional age is from 4.18 to 2 Ma. We carried out facies and geochemical analyses, such as total organic carbon (TOC), total sulfur (TS), and stable carbon isotope ratio of organic matter (δ^(13)C_org). The results are as follows: (1) Abundant land-derived organic matter was transported to the shelf and was preserved in the sediment in warm period (3.75-305 Ma). (2) productivity of marine organisms increased in the early cooling period (3.5-3.35 Ma),. (3) The considerable variations in TS, TOC andδ^(13)Corg are seen in cooling stage after 3 Ma, which succeeded to the Quaternary ice age. These considerable variations are shown inδ^(18)O curve of the same age.
Mappable units of submarine canyon-fill sediment are recognized in this area. A valley has a maximum depth of 100 m and is considered to be formed by submarine landslide, which took place after 2.7 Ma. Submarine canyon-fill sediments are composed of siltstone interbedded with thin sandstone layers, thick sandstone beds and slump deposits. Formation and filling of the submarine canyon might be controlled by climate cooling of latest Pliocene age.
|
