from 645 to 636 Ma and finally the Gaskiers glaciation
around 582 Ma. Marine glacial sedimentary formations at
low latitudes indicate that during the Sturtian and Marinoan
glaciations, the Earth was completely glaciated: these are the
famous episodes of Snowball Earth (Hoffman et al. 2017).
Directly on top of these glacial sedimentary formations we
find carbonate formations (currently, carbonate production is
mainly located in warm tropical seas). The rapidity of this
transition between glacial and carbonate formations (on the
scale of geological time) is a peculiarity in the climate history of the Earth. Numerous studies have been undertaken in
recent years to understand the entry and exit modalities of
these glacial phases (Hoffman et al. 2017; and Chap. 5).
The Precambrian/Cambrian boundary (542 Ma) marked a
new turning point in the Earth’s climate history. According
to oxygen isotopic ratio measurements, the mean global
temperatures of the Phanerozoic climate became stable
within a range comparable to that of the modern day
(Fig. 22.1b). This period was punctuated by three major
glaciations: one at the end of the Ordovician (around
443 Ma), during the Permo-Carboniferous (between 335 and
260 Ma) and at the end of the Cenozoic (the last 40 Myr).
Traces of the Ordovician glaciation are found in Africa,
particularly in the Sahara and South Africa but also on the
Arabian peninsula. This glaciation is estimated to have lasted a little more than one million years, and is marked by at
least three glacial cycles alternating with interglacial periods
(Ghienne et al. 2013). The glaciation is associated with a
major disruption in the carbon cycle but also with one of the
five mass extinctions of the Phanerozoic when close to 86%
of the marine benthic and planktonic species died out.
During the Silurian and Devonian periods, the Earth experienced a warmer global climate. Carbonate platforms,
which develop in warm seas, stretched from 45° S to 60° N.
An expansion of this scale would never be seen again
(Copper and Scotese 2003). The strong latitudinal expansion
of these carbonate platforms suggests weak latitudinal thermal gradients. The widespread evaporite facies suggest a
semi-arid to arid climate at subtropical latitudes.
The Devonian period is also marked by the colonization
of land surfaces by life. The first forests, made up of
Archeopteris, appeared at the end of the Devonian at around
370 Ma (Meyer-Berthaud et al. 1999). During the Silurian,
some plants, including bryophites, were the pioneers of this
land colonization that, until then, had been deserted and
barren. The emergence of the continental biosphere affected
the carbon cycle and probably influenced the climate of the
Earth (Le Hir et al. 2011). The end of the Devonian and the
beginning of the Carboniferous mark the return of glacial
periods and a more contrasted climate latitudinal gradient.
The Earth then underwent a glacial period which started in
the Carboniferous (*335 Ma) and which ended with the
Permian around 260 Ma (Montañez and Poulsen 2013). This
glaciation, which lasted 70 Ma, was punctuated by several
phases of advance and withdrawal of the ice sheets. This is
the longest and most important glacial episode of the entire
Phanerozoic. Sedimentary formations, striated floors and
‘dropstones’ (pieces of rock deposited onto unconsolidated
marine sediments by icebergs when they melted) are proof of
the presence of ice in South America, southern and eastern
Africa, on the Arabian peninsula, the Indian subcontinent
and Australia, that is, the whole southern part of the
Gondwana continent then located in the mid and high latitudes of the southern hemisphere.
At the end of the Carboniferous, while a cold climate
developed at the high and mid latitudes of the southern
hemisphere, paleoclimatic indicators indicate that there was
a tropical and humid climate over a part of Europe and North
America, then located close to the equator. At this time,
there was a strong contrast between the climates of low and
high latitudes.
These conditions disappeared in favor of a warmer and dryer
climate during the Late Permian. Wet climates were limited to
narrow bands around the equator and in the mid-latitudes. The
Paleozoic era ended with two mass extinctions, the first at the
end of the “Guadalupian” (*258 Ma) and the second at the
Permo-Trias boundary (*251 Ma) (Bond et al. 2010; Bond and
Wignall 2014). This last crisis is the most important mass
extinction of the Phanerozoic with the disappearance of 90% of
the fauna and flora (Erwin 1994). During this crisis, climate
indicators show significant warming, a disruption of the carbon
cycle as well as oceanic anoxia. An exceptionally high level of
volcanic activity leading to the contemporaneous formation of
the Siberian large igneous province is considered to be the main
cause of the extinction. Although the relationship between
volcanic activity and this crisis is not fully understood, it should
be noted that every ecological crisis of the Phanerozoic, whatever its magnitude, occurred simultaneously with the establishment of a large basaltic province through particularly intense
volcanic activity. After the Permo-Trias mass extinction, a warm
global climate became established during the Triassic. During
the Late Triassic, sedimentary facies in North America suggest a
strong seasonal precipitation caused by “mega-monsoon” patterns (Dubiel et al. 1991; Bahr et al. 2020). Subsequently, the
Earth experienced a colder global climate during the Jurassic.
The presence of ice caps at high latitudes has been suggested, but
this hypothesis is based on assumptions that have still to be
confirmed (Dromart et al. 2003).
Until the mid-1990s, the Cretaceous (145–65 Ma) was
described as a period with a uniformly warm global climate,
but the accumulation of data from different climate indicators
has completely changed our notions of the climate of this
period. The beginning of the Cretaceous period was cold,
probably with ice sheets, but experienced a particularly warm
period towards the middle of the Cretaceous, before cooling
towards the end of the period. On top of this long-term trend,
258
F. Fluteau and P. Sepulchre
around 582 Ma. Marine glacial sedimentary formations at
low latitudes indicate that during the Sturtian and Marinoan
glaciations, the Earth was completely glaciated: these are the
famous episodes of Snowball Earth (Hoffman et al. 2017).
Directly on top of these glacial sedimentary formations we
find carbonate formations (currently, carbonate production is
mainly located in warm tropical seas). The rapidity of this
transition between glacial and carbonate formations (on the
scale of geological time) is a peculiarity in the climate history of the Earth. Numerous studies have been undertaken in
recent years to understand the entry and exit modalities of
these glacial phases (Hoffman et al. 2017; and Chap. 5).
The Precambrian/Cambrian boundary (542 Ma) marked a
new turning point in the Earth’s climate history. According
to oxygen isotopic ratio measurements, the mean global
temperatures of the Phanerozoic climate became stable
within a range comparable to that of the modern day
(Fig. 22.1b). This period was punctuated by three major
glaciations: one at the end of the Ordovician (around
443 Ma), during the Permo-Carboniferous (between 335 and
260 Ma) and at the end of the Cenozoic (the last 40 Myr).
Traces of the Ordovician glaciation are found in Africa,
particularly in the Sahara and South Africa but also on the
Arabian peninsula. This glaciation is estimated to have lasted a little more than one million years, and is marked by at
least three glacial cycles alternating with interglacial periods
(Ghienne et al. 2013). The glaciation is associated with a
major disruption in the carbon cycle but also with one of the
five mass extinctions of the Phanerozoic when close to 86%
of the marine benthic and planktonic species died out.
During the Silurian and Devonian periods, the Earth experienced a warmer global climate. Carbonate platforms,
which develop in warm seas, stretched from 45° S to 60° N.
An expansion of this scale would never be seen again
(Copper and Scotese 2003). The strong latitudinal expansion
of these carbonate platforms suggests weak latitudinal thermal gradients. The widespread evaporite facies suggest a
semi-arid to arid climate at subtropical latitudes.
The Devonian period is also marked by the colonization
of land surfaces by life. The first forests, made up of
Archeopteris, appeared at the end of the Devonian at around
370 Ma (Meyer-Berthaud et al. 1999). During the Silurian,
some plants, including bryophites, were the pioneers of this
land colonization that, until then, had been deserted and
barren. The emergence of the continental biosphere affected
the carbon cycle and probably influenced the climate of the
Earth (Le Hir et al. 2011). The end of the Devonian and the
beginning of the Carboniferous mark the return of glacial
periods and a more contrasted climate latitudinal gradient.
The Earth then underwent a glacial period which started in
the Carboniferous (*335 Ma) and which ended with the
Permian around 260 Ma (Montañez and Poulsen 2013). This
glaciation, which lasted 70 Ma, was punctuated by several
phases of advance and withdrawal of the ice sheets. This is
the longest and most important glacial episode of the entire
Phanerozoic. Sedimentary formations, striated floors and
‘dropstones’ (pieces of rock deposited onto unconsolidated
marine sediments by icebergs when they melted) are proof of
the presence of ice in South America, southern and eastern
Africa, on the Arabian peninsula, the Indian subcontinent
and Australia, that is, the whole southern part of the
Gondwana continent then located in the mid and high latitudes of the southern hemisphere.
At the end of the Carboniferous, while a cold climate
developed at the high and mid latitudes of the southern
hemisphere, paleoclimatic indicators indicate that there was
a tropical and humid climate over a part of Europe and North
America, then located close to the equator. At this time,
there was a strong contrast between the climates of low and
high latitudes.
These conditions disappeared in favor of a warmer and dryer
climate during the Late Permian. Wet climates were limited to
narrow bands around the equator and in the mid-latitudes. The
Paleozoic era ended with two mass extinctions, the first at the
end of the “Guadalupian” (*258 Ma) and the second at the
Permo-Trias boundary (*251 Ma) (Bond et al. 2010; Bond and
Wignall 2014). This last crisis is the most important mass
extinction of the Phanerozoic with the disappearance of 90% of
the fauna and flora (Erwin 1994). During this crisis, climate
indicators show significant warming, a disruption of the carbon
cycle as well as oceanic anoxia. An exceptionally high level of
volcanic activity leading to the contemporaneous formation of
the Siberian large igneous province is considered to be the main
cause of the extinction. Although the relationship between
volcanic activity and this crisis is not fully understood, it should
be noted that every ecological crisis of the Phanerozoic, whatever its magnitude, occurred simultaneously with the establishment of a large basaltic province through particularly intense
volcanic activity. After the Permo-Trias mass extinction, a warm
global climate became established during the Triassic. During
the Late Triassic, sedimentary facies in North America suggest a
strong seasonal precipitation caused by “mega-monsoon” patterns (Dubiel et al. 1991; Bahr et al. 2020). Subsequently, the
Earth experienced a colder global climate during the Jurassic.
The presence of ice caps at high latitudes has been suggested, but
this hypothesis is based on assumptions that have still to be
confirmed (Dromart et al. 2003).
Until the mid-1990s, the Cretaceous (145–65 Ma) was
described as a period with a uniformly warm global climate,
but the accumulation of data from different climate indicators
has completely changed our notions of the climate of this
period. The beginning of the Cretaceous period was cold,
probably with ice sheets, but experienced a particularly warm
period towards the middle of the Cretaceous, before cooling
towards the end of the period. On top of this long-term trend,
258
F. Fluteau and P. Sepulchre