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Methods to Increase the Sensitivity of High Resolution Melting Single Nucleotide Polymorphism Genotyping in Malaria

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Calibrating rates of early Cambrian evolution.

S A Bowring¹, J P Grotzinger, C E Isachsen

¹Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge 02139, USA.

Science (New York, N.Y.)

|September 3, 1993

Summary

The Cambrian explosion began around 544 million years ago, with early stages lasting millions of years. New dating methods reveal a compressed timeline for Early Cambrian diversification and faunal turnover.

Keywords:

NASA Discipline Exobiology Non-NASA Center

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Area of Science:

Geology
Paleontology
Geochronology

Background:

The Cambrian period witnessed a rapid diversification of life, known as the Cambrian explosion.
Accurate dating of Cambrian rocks is crucial for understanding evolutionary rates but has been challenging.
High-precision geochronological methods are needed to resolve the timing of Early Cambrian events.

Purpose of the Study:

To precisely date the beginning of the Cambrian period and its early stages.
To quantify evolutionary rates during the Cambrian explosion.
To refine the timeline of Early Cambrian faunal diversification and turnover.

Main Methods:

Uranium-lead zircon geochronology was employed to date lower Cambrian rocks.
Geochronological data were analyzed to establish high-precision ages for Cambrian stages.
Radiometric dating techniques provided constraints on the duration of the Manykaian, Tommotian, and Atdabanian stages.

Main Results:

The Cambrian period commenced approximately 544 million years ago.
The oldest (Manykaian) stage of the Cambrian lasted at least 10 million years.
The Tommotian and Atdabanian stages collectively spanned only 5 to 10 million years.

Conclusions:

The Early Cambrian timeline is compressed, indicating a rapid pace of faunal diversification.
Subsequent Cambrian turnover events also occurred rapidly within a shorter timeframe.
Precise geochronology is essential for accurately interpreting evolutionary dynamics during the Cambrian.