Mesozoic-Cenozoic climatic history and causes of the glaciation

Frakes, Lawrence A.

doi:10.1029/gd015p0033

Cited by 26 publications

(11 citation statements)

References 51 publications

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“…The early Albian (Lower Cretaceous) also saw at least three flooding events. From the Turonian to the Santonian (90-85 Ma), there was a period of stability when average global temperatures and sea levels stabilized before starting to fall again at the beginning of the Campanian (84-74 Ma) (Frakes 1986;Hancock & Kauffman 1979). The late Maastrichtian (66 Ma) was marked by a significant cooling of the oceans and the Cretaceous-Tertiary (K-T) event was accompanied by a sudden drop in the eustatic sea level and global temperatures.…”

Section: The Palaeoecological Context Of Diatom Originsmentioning

confidence: 99%

“…The late Maastrichtian (66 Ma) was marked by a significant cooling of the oceans and the Cretaceous-Tertiary (K-T) event was accompanied by a sudden drop in the eustatic sea level and global temperatures. Frakes (1986) estimated that the drop in temperature might have been as much as 5ЊC worldwide. The fall in the eustatic sea level led to the disappearance of many epicontinental seas and subsequently some ocean basins (e.g.…”

Section: The Palaeoecological Context Of Diatom Originsmentioning

confidence: 99%

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Evolution of the diatoms: insights from fossil, biological and molecular data

2006

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Molecular sequence analyses have yielded many important insights into diatom evolution, but there have been few attempts to relate these to the extensive fossil record of diatoms, probably because of unfamiliarity with the data available, which are scattered widely through the geological literature. We review the main features of molecular phylogenies and concentrate on the correspondence between these and the fossil record; we also review the evolution of major morphological, cytological and life cycle characteristics, and possible diatom origins. The first physical remains of diatoms are from the Jurassic, and well-preserved, diverse floras are available from the Lower Cretaceous. Though these are unequivocally identifiable as centric diatoms, none except a possible Stephanopyxis can be unequivocally linked to lineages of extant diatoms, although it is almost certain that members of the Coscinodiscophyceae (radial centrics) and Mediophyceae (polar centrics) were present; some display curious morphological features that hint at an unorthodox cell division mechanism and life cycle. It seems most likely that the earliest diatoms were marine, but recently discovered fossil deposits hint that episodes of terrestrial colonization may have occurred in the Mesozoic, though the main invasion of freshwaters appears to have been delayed until the Cenozoic. By the Upper Cretaceous, many lineages are present that can be convincingly related to extant diatom taxa. Pennate diatoms appear in the late Cretaceous and raphid diatoms in the Palaeocene, though molecular phylogenies imply that raphid diatoms did in fact evolve considerably earlier. Recent evidence shows that diatoms are substantially underclassified at the species level, with many semicryptic or cryptic species to be recognized; however, there is little prospect of being able to discriminate between such taxa in fossil material.

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Section: The Palaeoecological Context Of Diatom Originsmentioning

confidence: 99%

Section: The Palaeoecological Context Of Diatom Originsmentioning

confidence: 99%

Evolution of the diatoms: insights from fossil, biological and molecular data

2006

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“…Como contrapartida ao consumo de CO 2 pela produção orgânica nos continentes, há a produção de CO 2 pela evasão marinha e pela oxidação de outros gases atmosféricos como o CO e o CH 4 . O autor postula que o vulcanismo tem importância secundária ao aporte do CO 2 à atmosfera, totalizando um pouco mais que 20% do total liberado pelos continentes e oceanos ( Fig.1) Neste sentido, parece existir consenso de que as modificações termais, pelo menos no Cretáceo foram primordialmente função da pressão de CO 2 atmosférico, embora opiniões divirjam sobre suas causas (Frakes 1986). O efeito estufa que afetou este período tem sido interpretado como resultante da produção orgânica desenvolvida principalmente nos oceanos.…”

Section: Considerações Acerca Da Evolução Climáticaunclassified

Evolução Climática Do Gondwana Na Região Centro-Sul Do Brasil E Seus Registros Geológicos Continentais Durante O Mesozóico, Enfatizando O Arco Do Paranaíba, a Borda Nne Da Bacia Do Paraná E a Porção Meridional Da Bacia Sanfrasciscana, No Oeste Do Estado D

Sgarbi¹,

Dardenne

1996

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Current theories suggest the the main cause of the temperature changes in Earth surface along the geological time, seems to be, as a concensus, the anomalous concentration of CO 2 , CH 4 and other gases in the terrestrial atmosphere. There are however divergences about the origin of these gases which are the main responsables for the greenhouse effect.This study discusses questions about the global climate changes in the geological past, commenting the mass-extinction periods of the Permian-Triassic (P/Tr) and Cretaceous/Tertiary (C/T) boundaries. The relationship between unusual high CO 2 levels in the atmosphere and mass-extinction events is commented. The origin of the greenhouse gases are attributed to: a) extensive outgassing of volatiles through of large volcanic events, or b) asteroid or cometary impact by bodies ranging up to 10 Km in diameters, or c) marine and terrestrial organic production by living organisms.Climatic changes have been detected in all the geological records, from Precambrian to Cenozoic. Tillites and varvites in Gondwana are features of Proterozoic and Paleozoic ice ages. The Mesozoic, on the other hand, had a global warm climate, exhibiting generally high level sea and low thermal variation between the poles and the equator. The Mesozoic continental geologic records in Gondwana are consequence of this arid climate, and the sedimentary rocks are mainly red-beds seguences or other related with arid/ semi-arid environments.The relationship between the climate, geological records and paleogeographical aspects in the Mesozoic Central-South Gondwana are presented, focussing the NNE border of the Paraná and the Southern Sanfranciscana basins, which occur in the western part of Minas Gerais state. The Parecis Basin that occurs in Mato Grosso State is also mentioned.These basins show sequences of varied rock types -volcanic and sedimentary ones -, and exhibit ages ranging from early to late Cretaceous.Other important paleogeographic feature studied occurs as a strip of intensely deformed Precambrian rocks forming a NW-SE tectonic arch, preserved as a succession of thrust slices. This is known as Alto do Paranaíba Arch or Alto do Paranaíba Anteclesis, (Ladeira et al. 1971, Grossi Sad et al 1971, a regional structure related with the emplacement of the Cretaceous Paraná and Sanfranciscana basins. O Mesozóico, tema do presente trabalho, também deixou profundas impressões no Brasil. Como um todo, pode ser caracterizado por uma época de clima predominantemente quente, com níveis marinhos altos e pouca variação térmica entre o equador e os polos, se comparado com as condições atuais. O registro geológico continental observado em parte do Brasil corrobora esta suposição climática, apesar das dificuldades inerentes ao estudo destas rochas, ao contrário daquelas crono-correlatas presentes em nossas bacias costeiras. As dificuldades devem-se, dentre outros fatores, à restrita importância econômica destas rochas, ao seu registro fragmentário, ao geralmente alto grau de alteração intempérica além...

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“…Theorists and experimentalists have come up with a consensus that temperature variations on Earth, since the early Cretaceous at least, were related to atmospheric CO 2 pressure, although opinions differ concerning the timing, the magnitude and the causes of the changes (Frakes, 1986). Budyko & Ronov (1979) had a simplistic model for relating the CO 2 budget to variable output of volcanic degassing, but their conclusion of a warming trend in late Cretaceous and middle Miocene time is contradicted by oxygen isotope data (Fig.…”

Section: Triassic Desert and Cretaceous Oceanmentioning

confidence: 99%

Is Gaia endothermic?

Hsü

1992

Geol. Mag.

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Geological evidence suggests that Gaia is endothermic: her body temperature has varied, but within limits; there has been no runaway greenhouse like Venus, nor deep freeze like Mars. This paper presents a hypothesis that the Earth's climate has been ameliorated by living organisms: they have served either as heaters or air-conditioners, and their ecological tolerance is the sensor of Gaia's thermostat. At the beginning, 3.8 or 3.5 Ga ago, only anaerobic autotrophs capable of tolerating high temperatures thinned out the atmospheric CO 2 through carbon fixation. Fossil organic carbon was utilized by anaerobic heterotrophs to reinforce the effectiveness of the late Archean greenhouse, when solar luminosity was weaker than it is now. With the increasing solar luminosity during early Proterozoic time, new life forms such as cyanobacteria evolved, removing CO 3 from the atmosphere and storing it in stromatolitic carbonates. Over-eager cyanobacteria may have consumed too much greenhouse CO 2 to cause glaciation. Their decline coincided in timing with the rise of the Ediacaran faunas which had no carbonate skeletons. The change in the mode of carbon-cycling may have started the warming trend after the Proterozoic glaciation. The Cambrian explosion was an event when skeletal eukaryotes usurped the function of prokaryotes in removing greenhouse CO 2 through CaCO 3 precipitation. With the evolution of land plants, coal-makers took over the 'air-conditioning' duty. They over-did it, and Permo-Carboniferous glaciation ensued. After a wholesale turnover of the faunas and floras at the end of the Palaeozoic, more CO 2 was released than fixed in early Mesozoic time. The warming trend reached its zenith in the early Cretaceous, when flowering trees and calcareous plankton began to flourish. The decline since then, with a temporary restoration during early Palaeogene time, could be a manifestation of the varying efficiency of extracting and burying carbon dioxide, in the form of inorganic and organic carbon. The relation of atmospheric CO 2 and climatic variation is documented by study of air bubbles in ice cores. Yet there is also correlation to astronomical cycles. The latter seem to have triggered changes which are amplified by feedback mechanisms of carbon cycling.

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Mesozoic-Cenozoic climatic history and causes of the glaciation

Cited by 26 publications

References 51 publications

Evolution of the diatoms: insights from fossil, biological and molecular data

Evolution of the diatoms: insights from fossil, biological and molecular data

Evolução Climática Do Gondwana Na Região Centro-Sul Do Brasil E Seus Registros Geológicos Continentais Durante O Mesozóico, Enfatizando O Arco Do Paranaíba, a Borda Nne Da Bacia Do Paraná E a Porção Meridional Da Bacia Sanfrasciscana, No Oeste Do Estado D

Is Gaia endothermic?

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