27
The Phanerozoic Climate
Yves Goddéris, Yannick Donnadieu, and Alexandre Pohl
The Phanerozoic period covers the last 542 million years of
Earth’s history, about 12% of the history of our planet. With
regard to the evolution of life, the Phanerozoic experienced
major events such as the rapid diversification of multicellular
organisms which first appeared in the Cambrian (541–
485 Ma), the colonization of continental surfaces by living
organisms during the Ordovician (485–444 Ma) and the
appearance of the first hominids about 8 million years ago.
Over this same period, the appearance of the Earth’s surface
changed considerably: the continental drift during the
Phanerozoic moved all of the continental masses situated in
the southern hemisphere and along the equator since the
Cambrian to join together around 280 million years ago to
form a supercontinent: the Pangea. This would then disintegrate during the Jurassic around 180 million years ago
with the emergence of the Atlantic Ocean.
Our understanding of the Phanerozoic climate, even if it
is still incomplete, has been rapidly evolving in recent years.
Data accumulated over the last few decades has improved
consistently in quality and the numerical models used to
reconstruct past climates have evolved considerably: they
have a better spatial resolution and include an increasing
number of processes. In general, it is true to say our conception of how and why the Earth’s climate evolved during
this key period in the history of life on Earth is now
undergoing a true revolution.
The Proxies for the Phanerozoic Climate
There are no direct indicators of climate conditions in the
geological past. However, qualitative reconstructions can be
produced from sedimentological and paleontological data,
and, in general, are more reliable than they are for the Precambrian. Geochemical data, in particular the isotopic indicators measured in marine sediments, provide some
quantification, but interpretation of them is rarely straightforward. Below we provide a non-exhaustive list of examples of indicators. Finally, we will highlight the indicators
that allow the reconstruction of CO 2 concentration in the
atmosphere over geological time.
Sedimentological Indicators
A compilation of sedimentological data indicative of glacial
climate was carried out in 1992 by Frakes et al. (1992). It
consists of an inventory of tillite-type glacial deposits (clays
formed from erosion products resulting from the friction of
glaciers on their bedrock) and, on the other hand, a reconstruction of the minimum paleolatitude attained by rock
debris carried by sea ice. The result shows a fluctuation of
hot and cold modes over a period of approximately 135 Ma.
The coldest climate mode was identified during the
Permo-Carboniferous glaciation.
A more recent study provides results in agreement with
those of Frakes et al. (1992). Boucot et al. (2004) compiled
data on continental coal deposits, indicators of an arid climate, as a function of paleogeography and time. They constructed a qualitative curve of variations on the equator-pole
climate gradient for the entire Phanerozoic. They interpret
the existence of weak gradients as the sign of a warm
climate.
Y. Goddéris (&)
Géosciences Environnement Toulouse, CNRS-Université de
Toulouse III, UMR 5563, Toulouse, France
e-mail: yves.godderis@gmail.com
Y. Donnadieu Á A. Pohl
Aix-Marseille Université, CNRS, IRD, Coll France, CEREGE,
Aix-en-Provence, France
© Springer Nature Switzerland AG 2021
G. Ramstein et al. (eds.), Paleoclimatology, Frontiers in Earth Sciences,
https://doi.org/10.1007/978-3-030-24982-3_27
359
The Phanerozoic Climate
Yves Goddéris, Yannick Donnadieu, and Alexandre Pohl
The Phanerozoic period covers the last 542 million years of
Earth’s history, about 12% of the history of our planet. With
regard to the evolution of life, the Phanerozoic experienced
major events such as the rapid diversification of multicellular
organisms which first appeared in the Cambrian (541–
485 Ma), the colonization of continental surfaces by living
organisms during the Ordovician (485–444 Ma) and the
appearance of the first hominids about 8 million years ago.
Over this same period, the appearance of the Earth’s surface
changed considerably: the continental drift during the
Phanerozoic moved all of the continental masses situated in
the southern hemisphere and along the equator since the
Cambrian to join together around 280 million years ago to
form a supercontinent: the Pangea. This would then disintegrate during the Jurassic around 180 million years ago
with the emergence of the Atlantic Ocean.
Our understanding of the Phanerozoic climate, even if it
is still incomplete, has been rapidly evolving in recent years.
Data accumulated over the last few decades has improved
consistently in quality and the numerical models used to
reconstruct past climates have evolved considerably: they
have a better spatial resolution and include an increasing
number of processes. In general, it is true to say our conception of how and why the Earth’s climate evolved during
this key period in the history of life on Earth is now
undergoing a true revolution.
The Proxies for the Phanerozoic Climate
There are no direct indicators of climate conditions in the
geological past. However, qualitative reconstructions can be
produced from sedimentological and paleontological data,
and, in general, are more reliable than they are for the Precambrian. Geochemical data, in particular the isotopic indicators measured in marine sediments, provide some
quantification, but interpretation of them is rarely straightforward. Below we provide a non-exhaustive list of examples of indicators. Finally, we will highlight the indicators
that allow the reconstruction of CO 2 concentration in the
atmosphere over geological time.
Sedimentological Indicators
A compilation of sedimentological data indicative of glacial
climate was carried out in 1992 by Frakes et al. (1992). It
consists of an inventory of tillite-type glacial deposits (clays
formed from erosion products resulting from the friction of
glaciers on their bedrock) and, on the other hand, a reconstruction of the minimum paleolatitude attained by rock
debris carried by sea ice. The result shows a fluctuation of
hot and cold modes over a period of approximately 135 Ma.
The coldest climate mode was identified during the
Permo-Carboniferous glaciation.
A more recent study provides results in agreement with
those of Frakes et al. (1992). Boucot et al. (2004) compiled
data on continental coal deposits, indicators of an arid climate, as a function of paleogeography and time. They constructed a qualitative curve of variations on the equator-pole
climate gradient for the entire Phanerozoic. They interpret
the existence of weak gradients as the sign of a warm
climate.
Y. Goddéris (&)
Géosciences Environnement Toulouse, CNRS-Université de
Toulouse III, UMR 5563, Toulouse, France
e-mail: yves.godderis@gmail.com
Y. Donnadieu Á A. Pohl
Aix-Marseille Université, CNRS, IRD, Coll France, CEREGE,
Aix-en-Provence, France
© Springer Nature Switzerland AG 2021
G. Ramstein et al. (eds.), Paleoclimatology, Frontiers in Earth Sciences,
https://doi.org/10.1007/978-3-030-24982-3_27
359