An Overview of Paleo-Climate Evidence in Egypt
27
as well as some of the benthic groups such as Rugose corals, Trilobites, Ostracods
and Brachiopods [10]. The last around 359 Maand includes extinction of 30% of
Genera including several species of affected Placoderms, ammonoids, conodonts,
stromatoporoids, rugose corals, trilobites and ostracods. The CO 2 levels decreased
from ranges of 3200–5200 ppm to below 500 ppm [57]. In the terrestrial realm, the
development in the plant megaphyll leaves containing high stomata density allowed
vegetation to adapt to the cool low-CO 2 conditions of the fore coming cold periods
[14, 58]. The land had been colonized by plants and insects. In particular, the rapid
rising of Archaeopteris forests during the closing stages of the Devonian [59]. The
sedimentary record includes evidence reveal several environmental changes Such
as exists of widespread anoxia in oceanic bottom waters; the high rate of carbon
burial [59], tropical reef and benthic organisms were devastated. The most important
evidence is the cyclic sea-level changes around the Frasnian–Famennian Kellwasser
event, in which the sea level rise is associated with the onset of anoxic deposits [60].
4.3 Permo-Triassic Mass Extinction
The Great Dying, occurred between 251.941 ± 0.037 and 251.880 ± 0.031 Ma ago,
and lasting for the duration of 60 ± 48 ka [61]. The Earth’s largest mass extinction
event that killed 57% of all families, 83% of all genera and 90–96% of all species
[62]. These percentage includes about 96% of all marine species and about 70% of
terrestrial species and insects [63]. This event is associated with a major eruption
of Siberian volcanism [64, 39, 65]; Fig. 3) with a large asteroid impact (Araguinha,
Brazil, with a diameter of 40 km). The atmospheric CO 2 level is increased to about
3400 ppm [66, 67]. The geochemical investigation across the Permo-Triassic boundary [68] based on isotopic d
13 C and d
34 S indicates that increasing the aridity that led
to dropping in the rate of organic burial starting from late Permian. The aridity led to
a decrease in on land biomass from forests to grassland. An abrupt drop in oxygen
level and increasing both pyrite and organic carbon led to rising of euxinic marine
conditions. The consequence of the previous conditions is to forsees the extinction
of vertebrates and loss of giant insects and amphibians, as well as increase in ocean
acidity, melting of polar ice, change in ocean circulation speed that result in rising anoxia producing a huge amount of H 2 S that released to the atmosphere and
accelerate the sea and land mass extinction [19].
4.4 Triassic- Jurassic Mass Extinction
Took place around 201.3 Ma characterized by the extinction of 70–75% of all species
[69] including Most archosaurs, therapsids, and the large amphibians were vanished,
only dinosaurs were resisted with few terrestrial fauna. The aquatic ecosystems were
27
as well as some of the benthic groups such as Rugose corals, Trilobites, Ostracods
and Brachiopods [10]. The last around 359 Maand includes extinction of 30% of
Genera including several species of affected Placoderms, ammonoids, conodonts,
stromatoporoids, rugose corals, trilobites and ostracods. The CO 2 levels decreased
from ranges of 3200–5200 ppm to below 500 ppm [57]. In the terrestrial realm, the
development in the plant megaphyll leaves containing high stomata density allowed
vegetation to adapt to the cool low-CO 2 conditions of the fore coming cold periods
[14, 58]. The land had been colonized by plants and insects. In particular, the rapid
rising of Archaeopteris forests during the closing stages of the Devonian [59]. The
sedimentary record includes evidence reveal several environmental changes Such
as exists of widespread anoxia in oceanic bottom waters; the high rate of carbon
burial [59], tropical reef and benthic organisms were devastated. The most important
evidence is the cyclic sea-level changes around the Frasnian–Famennian Kellwasser
event, in which the sea level rise is associated with the onset of anoxic deposits [60].
4.3 Permo-Triassic Mass Extinction
The Great Dying, occurred between 251.941 ± 0.037 and 251.880 ± 0.031 Ma ago,
and lasting for the duration of 60 ± 48 ka [61]. The Earth’s largest mass extinction
event that killed 57% of all families, 83% of all genera and 90–96% of all species
[62]. These percentage includes about 96% of all marine species and about 70% of
terrestrial species and insects [63]. This event is associated with a major eruption
of Siberian volcanism [64, 39, 65]; Fig. 3) with a large asteroid impact (Araguinha,
Brazil, with a diameter of 40 km). The atmospheric CO 2 level is increased to about
3400 ppm [66, 67]. The geochemical investigation across the Permo-Triassic boundary [68] based on isotopic d
13 C and d
34 S indicates that increasing the aridity that led
to dropping in the rate of organic burial starting from late Permian. The aridity led to
a decrease in on land biomass from forests to grassland. An abrupt drop in oxygen
level and increasing both pyrite and organic carbon led to rising of euxinic marine
conditions. The consequence of the previous conditions is to forsees the extinction
of vertebrates and loss of giant insects and amphibians, as well as increase in ocean
acidity, melting of polar ice, change in ocean circulation speed that result in rising anoxia producing a huge amount of H 2 S that released to the atmosphere and
accelerate the sea and land mass extinction [19].
4.4 Triassic- Jurassic Mass Extinction
Took place around 201.3 Ma characterized by the extinction of 70–75% of all species
[69] including Most archosaurs, therapsids, and the large amphibians were vanished,
only dinosaurs were resisted with few terrestrial fauna. The aquatic ecosystems were