| Project/Area Number |
12640451
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Stratigraphy/Paleontology
|
|---|
| Research Institution | Chiba University |
|---|
Principal Investigator |
KOTAKE Nobuhiro Chiba Univ., Faculty of Science, Associate Prof., 理学部, 助教授 (00205402)
|
|---|
| Project Period (FY) |
2000 – 2002
|
| Project Status |
Completed (Fiscal Year 2002)
|
| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2002: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2001: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2000: ¥1,300,000 (Direct Cost: ¥1,300,000)
|
|---|
| Keywords | trace fossil / bioturbation / nest activity / feeding behavior / Mesozoic / 中生代 / 接食活動 / 時代変遷 |
|---|
| Research Abstract |
The principal aim of this research is to understand the mechanism and process of bioturbation induced by the activity of benthic animals throughout the Phanerozoic on the basis of the data from the analysis of trace fossils which represent a fossil record of the ancient marine benthic animals. In addition, to clarify the relationship between the bioturbation phenomena and the change in life style of the progenitors of trace fossils examined herein is another important goal of this research. The following conclusions are obtained :
1) Biogenic disturbance, which was induced by feeding behavior and nest excavation activity, represents a major factor for the vertical mixing of surface sediments deposited under the marine environments.
2) In the present study, it was firstly found that bioturbation of the marine sediments was drastically changed at the time around the boundary between the Jurassic and Cretaceous ages.
3) The drastic change in bioturbation mentioned above seems to be closely related to a phenomenon that the life style of benthic animals has changed in response to the extremely increasing of food flux of phytoplankton origin. In addition, it is very important to discuss on the change in bioturabtion at the Mesozoic that appearance of the ray fish which feeds deep burrowers and prosperity of special group of crustaceans which produced complicated, large-scaled networks deep in the sediment.
|
