2003 Fiscal Year Final Research Report Summary
Testing of the Snowball Earth hypothesis in terms of the cap carbonates, Namibia
| Project/Area Number |
13573003
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
固体地球物理学
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| Research Institution | Gifu University |
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Principal Investigator |
KAWAKAMI Shin-ichi Gifu Universit, Faculty of Education, Professor, 教育学部, 教授 (80183036)
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| Co-Investigator(Kenkyū-buntansha) |
NOHDA Susumu Kumamoto University, Faculty of Science, Professor, 理学部, 教授 (30065841)
OHNO Terufumi The Kyoto University Museum, Professor, 総合博物館, 教授 (40194245)
TAKANO Masao Nagoya University, Graduate School of Environment, Associate Professor, 大学院・環境学研究科, 助教授 (90262849)
SAKAI Hideo Toyama University, Faculty of Science, Professor, 理学部, 教授 (30134993)
KANI Tomomi Kumamoto University, Faculty of Science, Assistant Professor, 理学部, 助手 (60332863)
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| Project Period (FY) |
2001 – 2003
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| Keywords | Snowball Earth hypothesis / Neoproterozoic / Namibia / carbonate / diamictite / climate change / banded iron-formation / Precambrian |
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| Research Abstract |
The purpose of this study is to test the Snowball Earth hypothesis, which suggests that the entire Earth surface was covered with icesheet in several times during Neoproterozoic era. For this purpose, we visited Namibia in winter seasons from 2001 to 2003 and investigated ouccrops of diamictites, cap carbonates, and iron formations associated with diamictites. The rock specimens sampled from Ghaab diamictites near Fransfountain was used for rheological analysis which revealed that the diamicites was compressed by the overburden pressures after deposition. The cap carbonates were used for geochemical analysis. The calcite dolomite cycles found in Rasthof cap carbonates were correlated in several outcrops. A slump strucutes occurring in the cycles suggested that the calcite dolomite cycles existed before the strata was consolidated. This means that the dolomites of cap carbonates were primary origin. The carbonate rocks were also used for geochronological studies. The Ediacaran fossils found in southern Namibia and the White Sea area, Russia were also studied. The results of these studies were discussed in terms of several working hypotheses of the Neoproterozoic glaciation. The testing of the Snowball Earth hypothesis and its relation to the emergence of animal life of the Ediacaran type are still important topics in Earth Science.
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