Chapter 1 - Chemical Reactions and Equations. Chapter 3 - Metals and Non-metals. Chapter 4 - Carbon and Its Compounds. Chapter 5 - Periodic Classification of Elements. Chapter 6 - Life Processes. Chapter 7 - Control and Coordination.
Polar stratospheric clouds have a great impact on radiative forcing. Due to their minimal albedo properties and their optical thickness, polar stratospheric clouds act similar to a greenhouse gas and traps outgoing longwave radiation. Different types of polar stratospheric clouds occur in the atmosphere: polar stratospheric clouds that are created due to interactions with nitric or sulfuric acid and water Type I or polar stratospheric clouds that are created with only water ice Type II.
Methane is an important factor in the creation of the primary Type II polar stratospheric clouds that were created in the early Eocene. When methane is oxidized, a significant amount of water vapor is released.
Another requirement for polar stratospheric clouds is cold temperatures to ensure condensation and cloud production. Polar stratospheric cloud production, since it requires the cold temperatures, is usually limited to nighttime and winter conditions.
With this combination of wetter and colder conditions in the lower stratosphere, polar stratospheric clouds could have formed over wide areas in Polar Regions. To test the polar stratospheric clouds effects on the Eocene climate, models were run comparing the effects of polar stratospheric clouds at the poles to an increase in atmospheric carbon dioxide. A multitude of feedbacks also occurred in the models due to the polar stratospheric clouds' presence.
Any ice growth was slowed immensely and would lead to any present ice melting. Only the poles were affected with the change in temperature and the tropics were unaffected, which with an increase in atmospheric carbon dioxide would also cause the tropics to increase in temperature. Due to the warming of the troposphere from the increased greenhouse effect of the polar stratospheric clouds, the stratosphere would cool and would potentially increase the amount of polar stratospheric clouds.
While the polar stratospheric clouds could explain the reduction of the equator to pole temperature gradient and the increased temperatures at the poles during the early Eocene, there are a few drawbacks to maintaining polar stratospheric clouds for an extended period of time.
Separate model runs were used to determine the sustainability of the polar stratospheric clouds. In addition, the amounts of ice and condensation nuclei would need to be high in order for the polar stratospheric cloud to sustain itself and eventually expand.
These hyperthermals led to increased perturbations in planktonic and benthic foraminiferawith a higher rate of sedimentation as a consequence of the warmer temperatures. Recent analysis of and research into these hyperthermals in the early Eocene has led to hypotheses that the hyperthermals are based on orbital parameters, in particular eccentricity and obliquity. The Eocene is not only known for containing the warmest period during the Cenozoic, but it also marked the decline into an icehouse climate and the rapid expansion of the Antarctic ice sheet.
Nov 21, Use of Carbon dating to determine the age of the fossil For more detail visit multicoingames.com The Eocene (/ ? i?. ? ? s i? n, ? i?. o?-/ EE-?-seen, EE-oh-) Epoch is a geological epoch that lasted from about 56 to million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic multicoingames.com name Eocene comes from the Ancient Greek ??? (e?s, "dawn") and ?????? (kainos, "new") and refers to the "dawn" of modern ('new') fauna that. Oct 03, A formula to calculate how old a sample is by carbon dating is: t = [ ln (Nf/No) / ] x t1/2. t = [ ln (N f /N o) / ] x t 1/2. where ln is the natural logarithm, N f /N o is the percent of carbon in the sample compared to the amount in living tissue, and t 1/2 is the half-life of carbon (5, years). So, if you had a fossil that had 10 percent carbon compared to.
Isotopes of carbon and oxygen indicate a shift to a global cooling climate. The increased warmth at the poles, the isolated Arctic basin during the early Eocene, and the significantly high amounts of carbon dioxide possibly led to azolla blooms across the Arctic Ocean.
The ability for the azolla to sequester carbon is exceptional, and the enhanced burial of azolla could have had a significant effect on the world atmospheric carbon content and may have been the event to begin the transition into an ice house climate. Cooling after this event continued due to continual decrease in atmospheric carbon dioxide from organic productivity and weathering from mountain building.
This warming event is known as the Middle Eocene Climatic Optimum. The warming is considered to be primarily due to carbon dioxide increases, because carbon isotope signatures rule out major methane release during this short-term warming.
Another possible cause of atmospheric carbon dioxide increase could have been a sudden increase due to metamorphic release during the Himalayan orogeny ; however, data on the exact timing of metamorphic release of atmospheric carbon dioxide is not well resolved in the data.
Cooling continued throughout the rest of the late Eocene into the Eocene-Oligocene transition.
During the cooling period, benthic oxygen isotopes show the possibility of ice creation and ice increase during this later cooling. At the beginning of the Eocene, the high temperatures and warm oceans created a moist, balmy environment, with forests spreading throughout the Earth from pole to pole.
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Apart from the driest desertsEarth must have been entirely covered in forests. Polar forests were quite extensive.
Free download of NCERT Solutions for Class 10 Science (Chemistry) Chapter 4 - Carbon and Its Compounds solved by Expert Teachers as per NCERT (CBSE) Book guidelines. All Chapter 4 - Carbon and Its Compounds Exercise Questions with Solutions . Carbon dating suggests that images were created between 15, and 17, years ago in the caves near Montignac, in the Dordogne region, in south-west France. Whereas the earlier pictographic representations are about 5, years old while the most recent written language is . Free Download - Best collection of CBSE topper Notes, Important Questions, Sample papers and NCERT Solutions for CBSE Class 9 Chemistry Structure of Atom. The entire NCERT textbook questions have been solved by best teachers for you.
Fossils and even preserved remains of trees such as swamp cypress and dawn redwood from the Eocene have been found on Ellesmere Island in the Arctic. Even at that time, Ellesmere Island was only a few degrees in latitude further south than it is today.
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Fossils of subtropical and even tropical trees and plants from the Eocene also have been found in Greenland and Alaska. Tropical rainforests grew as far north as northern North America and Europe. Palm trees were growing as far north as Alaska and northern Europe during the early Eocene, although they became less abundant as the climate cooled.
Dawn redwoods were far more extensive as well. The earliest definitive Eucalyptus fossils were dated from Cooling began mid-period, and by the end of the Eocene continental interiors had begun to dry out, with forests thinning out considerably in some areas.
The newly evolved grasses were still confined to river banks and lake shores, and had not yet expanded into plains and savannas. The cooling also brought seasonal changes. Deciduous trees, better able to cope with large temperature changes, began to overtake evergreen tropical species. By the end of the period, deciduous forests covered large parts of the northern continents, including North America, Eurasia and the Arctic, and rainforests held on only in equatorial South AmericaAfricaIndia and Australia.
Antarcticawhich began the Eocene fringed with a warm temperate to sub-tropical rainforestbecame much colder as the period progressed; the heat-loving tropical flora was wiped out, and by the beginning of the Oligocene, the continent hosted deciduous forests and vast stretches of tundra.
During the Eocene, plants and marine faunas became quite modern. Many modern bird orders first appeared in the Eocene. The Eocene oceans were warm and teeming with fish and other sea life.
The first carcharinid sharks. The oldest known fossils of most of the modern mammal orders appear within a brief period during the early Eocene.
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At the beginning of the Eocene, several new mammal groups arrived in North America. These modern mammals, like artiodactylsperissodactylsand primateshad features like long, thin legsfeet, and hands capable of grasping, as well as differentiated teeth adapted for chewing.
Dwarf forms reigned.
They were also smaller than the mammals that followed them. It is assumed that the hot Eocene temperatures favored smaller animals that were better able to manage the heat. Both groups of modern ungulates hoofed animals became prevalent because of a major radiation between Europe and North America, along with carnivorous ungulates like Mesonyx. Early forms of many other modern mammalian orders appeared, including batsproboscidians elephantsprimates, rodentsand marsupials.
Older primitive forms of mammals declined in variety and importance. Marine fauna are best known from South Asia and the southeast United States. Basilosaurus is a very well known Eocene whalebut whales as a group had become very diverse during the Eocene, which is when the major transitions from being terrestrial to fully aquatic in cetaceans occurred.
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The first sirenians were evolving at this time, and would eventually evolve into the extant manatees and dugongs. Reptile fossils from this time, such as fossils of pythons and turtlesare abundant. The remains of Titanoboaa snake recorded as attaining up to Insects found in Eocene deposits mostly belong to genera that exist today, though their range has often shifted since the Eocene. For instance the bibionid genus Plecia is common in fossil faunas from presently temperate areas, but only lives in the tropics and subtropics today.
Brontotherium Titanotheriidae. From Wikipedia, the free encyclopedia. Second epoch of the Paleogene period. This section needs expansion. Chapter 1 - Chemical Reactions and Equations.
Carbon 14 Dating Problems - Nuclear Chemistry \u0026 Radioactive Decay
Chapter 3 - Metals and Non-metals. Chapter 4 - Carbon and Its Compounds.
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Chapter 5 - Periodic Classification of Elements. Chapter 6 - Life Processes. Chapter 7 - Control and Coordination.
Chapter 8 - How do Organisms Reproduce? Chapter 9 - Heredity and Evolution. Chapter 10 - Light Reflection and Refraction.
Chapter 11 - Human Eye and Colourful World. Potassium is another radioactive element naturally found in your body and has a half-life of 1. The use of various radioisotopes allows the dating of biological and geological samples with a high degree of accuracy. However, radioisotope dating may not work so well in the future. Anything that dies after the s, when Nuclear bombsnuclear reactors and open-air nuclear tests started changing things, will be harder to date precisely.
How Carbon is Made. Dating a Fossil. Lots More Information. Geological Survey's Publication "Geotime". Related Content " ". Is Permafrost Really, Well, Permanent?