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09:06
Removal of Exogenous Materials from the Outer Portion of Frozen Cores to Investigate the Ancient Biological Communities Harbored Inside
Published on: July 3, 2016
Isotopes, ice ages, and terminal Proterozoic earth history
A J Kaufman1, A H Knoll, G M Narbonne
1Botanical Museum, Harvard University, Cambridge, MA 02138, USA.
Summary
Ancient glacial deposits reveal four to five ice ages in the Proterozoic Eon. High organic carbon burial likely reduced greenhouse gases, triggering these glaciations and impacting early animal evolution.
Area of Science:
- Paleoclimatology
- Geochronology
- Paleontology
Background:
- The terminal Proterozoic Eon experienced significant climate shifts.
- Understanding the drivers of ancient glaciations is crucial for climate modeling.
- The early fossil record of animals is poorly resolved in time.
Purpose of the Study:
- To correlate ancient glacial deposits with paleoclimatic data.
- To investigate the relationship between carbon cycling and glaciation.
- To refine the timeline of Proterozoic environmental and evolutionary events.
Main Methods:
- Detailed stratigraphic correlation of glacial deposits.
- Analysis of carbon and strontium isotopes in seawater for temporal records.
- Examination of C-isotopic excursions and glaciogenic rock relationships.
Main Results:
- Identification of four to five discrete ice ages in the terminal Proterozoic.
- Strong correlation between carbon-isotopic excursions and glaciogenic rocks.
- Evidence suggesting high organic carbon burial rates preceded glaciations.
Conclusions:
- Reduced atmospheric greenhouse capacity, driven by organic carbon burial, likely facilitated Proterozoic glaciations.
- A refined framework of time and environmental change aids understanding of early animal evolution.
- This study enhances stratigraphic and evolutionary pattern resolution in the early fossil record.
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