Snowball Earth Hypothesis example essay topic

State of research on the 'Snowball Earth Hypothesis " The 'Snowball Earth Hypothesis' also known as the " Varan gia glaciation' is a hypothesis presented in 2001 by Geologist Paul Hoffman. (Wikipedia, 2002) The hypothesis purposes that 540 million years ago during the Neoproterozoic, a meter thick of ice covered the oceans and glaciers the continents for 100 million years. Albedo; when ice and snow reflect solar radiation into space, in absents of greenhouse gases, which don't exist within the atmosphere, heat therefore escapes the planet. A condition of temperature disequilibrium occurs, when freezing cold reaches a state, the climate never warms to normal, and cold freezes the hemisphere and buries it under massive glaciation.

The glaciers begin when a green house gas, carbon dioxide, is depleted from erosion of silicates. Once the atmosphere is depleted of carbon dioxide, it can not absorb solar radiation. The global temperatures drops to cold and glaciation occurs, glaciation continues, temperature gradients drop further to colder, below freezing, cold is irreversible, glaciers reflect solar radiation into space. The lack of atmospheric carbon dioxide prevented greenhouse from occurring, earth is frozen until the hemisphere is totally glaciated.

(Hoffman, 1998) De glaciation can occur when volcanic eruptions saturate the atmosphere with carbon dioxide gas and resume the greenhouse effect on climate. Solar radiation is absorbed by greenhouse gases, rewarming the climate. A dramatic expansion of the biosphere occurred. ('Cold') History of 'Snowball Earth Hypothesis'A tree toppled during a hurricane.

A 700 million year old rock bed was discovered in Appalachia. The rock, consisted of basalt -size cobbles mixed with a slurry of fine silt and sand. The region consisting of Appalachian Blue Ridge range, Sharp Top mountain had once bordered a seaway cutting through Rhodia, a giant continent that included most of the worlds land. Sharp Top contained signs of tides, indicating the glacier had st reached down to the sea. During this time, Virginia was 15' to 30' of the equator.

Scientist wanted to know why ice was on the equator during the Neoproterozoic era. (Monastersky, 1998) The team of scientists consisted of a bio geologist, geochemist, and tectonic geologist with the common goal of understanding the coevolution of life and environments in Earth History. The research centered on three critical intervals of planetary change and major transitions in the co-evolution of life on earth. (Knoll) In 1998 the team of geologists had culled clues from Namibia and fashioned the Snowball hypothesis. (, 1998) Source and Nature of research The research into collecting data proving or disproving Snowball Earth was conducted by geologists who had collected Neoproterozoic rock samples in Australia, China, western U.S., Arctic Islands of Svalbard and the Namibia coast. (Hoffman, et al.

1998) Research included conducting a geologic survey of the Congo craton, facies of Gharb formation fill valleys. Rock specimens were taken from the lower glacial intervals (Chugs Formation) to just beneath the unconformity at the base of Mulder group, Southern Damar a margin of the craton and Koko craton, Kalahari craton, Amadeus basin. These rock specimens were micro drilled and the elements Sr, Mn, Fe, Ca, Mg were measured for abundance using inductively coupled plasma emission spectroscopy to assess dia genetic alteration. These sample were analyzed offline for DELTA 13 CARBON AND DELTA 18 OXYGEN after digestion for 3 hours in H 2 po 4 at 50'C to insure complete reaction of dolomite: the evolved gas was measured on a finnegan mat, other research consisted of fusions sector mass spectrometer, graphite -furnace atomic absorption spectroscopy, leached in NH 4 CH 3 COO, digestion in weak acetic acid. (Hoffman, et. al. 1998) Analysis of 'Snowball Earth Hypothesis " The data obtained from cap carbonates deposited where glaciers melted and sea level climbed, carbonates deposited on glacier submerged karst, forming guyots, other areas, iron rock deposits were found that aged (540 ma?) (Hoffman, et. al.

2002) The cap carbonates are located above glacial strata that form a shape knife edge bound ry. The Namibia cap carbonates formation is a rocky cliff along the Namibia skeleton coast. There superposition of the glacial strata to cap carbonates. The specimens gathered from that strata are uniformity to Neo paleozoic glaciation samples from other excavations. The comprehensive data help scientist conclude Neopaleozic glaciers had existed for 100 million years, it's believed the glaciers formed when animal life radiated and then mass extinction followed. The enormity of the glaciation cover makes a vivid picture of a Earth receiving Sun light without atmosphere to retain heat.

There was no data of Snowball Earth glacial succession. What glaciers and where had the first occurred -- what glaciers had rescinded eventually melting into water. The research had established the initial span of glaciation, the nature of the rock, and perhaps why massive glaciation happened. Scientist established through mathematical models, based on the rock samples, a phenomenon of ice-albedo feedback. Geographic surfaces that reflect the Sun's incoming energy. (Hoffman, et. al.

2000) This model was used to describe atmospheric conditions that can initiate Snowball Earth. Discussion Research concluded that DELTA 13 CARBON of -5% indicated there was no photosynthesis on earth. Thus, no biological life existed in Snowball Earth. (Cold) Iron rock deposits also proved oxygen wasn't present to oxidize iron, Therefore a Snowball earth was glaciated.

(Hoffman, et. al. 2002) The DELTA 13 CARBON further indicated that massive, icy methane hydrate on the sea floor had destabilized, methane a powerful gas, leaked into the atmosphere. limiting carbon dioxide. Methane disappeared quickly, from the atmosphere. If a methane leak had stopped, it would cause a loss of greenhouse, triggering albedo (when ice and snow reflect solar radiation into space and no atmospheric greenhouse gasses exist to trap or hold radiation). Before volcano's would stabilize the atmosphere with carbon dioxide.

(Simpson, 2001) Scientist Martin Kennedy disputes the Snowball Earth conclusion. The carbon levels actually prove iron rock deposits formed beneath a glacier, not from atmosphere void of oxygen. Snowball Earth could not be true, if the oceans were glaciated, there would be no life. (Kennedy, et. al. 2001) This argument was refuted by kennedy, if volcanoes saturated the atmosphere with CO 2, the glaciers didn't freeze through the oceans floor.

Some life survived at the ocean floor around subsurface volcanoes creating geothermal heat. (Hoffman, 2000) Scientist refuted, responding the equatorial region was not glaciated so ocean life went on as usual. (Kennedy, 1998) Conclusion Snowball Earth has established itself as the perfect model of albedo, the mechanism and controls of mechanisms triggering and reversing albedo overload. While it yet can't prove certain events occurring at the biosphere level, it dose explain how might the biosphere survive and flourish. A totally frozen earth with pockets of organisms living around submerged volcanic activity or a equatorial ocean where life continued as usual, organisms awaiting lived in a warm ocean amidst glaciers on the continents. Volcanoes reverse albedo.

Thus. a habitable climate returns to earth. The actions of a volcano here, seem no different to keeping a sacred fire. Since the fire of a volcano merely is the hot earth that could have burned the proterozoic forest... Burning man, a celebration in the high desert of Nevada, a blazing gesture, perhaps humanities answer to replenishing the atmosphere with carbon dioxide without a passive loss of silicate to global warming vis a vis albedo, over freezing. Snowball Earth right now only exist in hypothesis, cap carbonates, methane and carbon dioxide are hotly debated and coolly challenged. Their is no perfect answer yet, though accomplished is a further understanding of time and its mechanisms of change.

Bibliography

Hoffman Pau F. l: Halverson, Galen P. ; Grot zing, John P. (2002) Are Proterozoic cap carbonates and is optic excursions a record of gas hydrate destabilization following Earths coldest intervals? Geology 286-287 Hoffman, Paul F.
Schram, Daniel P. 'Snowball Earth's scientific America 21 Jan 2000 Scientific American Online.
Online 31 Mar 2003 Kennedy, Martin J.
Christie - Blick, Nicholas; Prave, Anthony R. (2001) Carbon isotopic composition of Neoproterozoic glacial carbonates as a test of pale oceanographic models for Snowball Earth phenomena.
Geology 1135-1138 Kennedy, Martin J. ; Run neger, Bruce; Prave, Anthony R. ; Hoffmann, K -H. ; Arthur, Michael A. (1998) Two or four Neoproterozoic glaciations? Geology 1059-1063 Knoll, Andy 'The Planet are Context of Biological Evolution' Lead Teams Online.
NASA Astrobiology Institute 2 Apr 2003 Monastersky, Richard, 'Popsicle Planet, The king of all ice ages may have spurred animal evolution' 22 Aug 1998 Science News Online Online.
Science Service 2 Apr 2003 Simpson, Sarah 'Triggering a Snowball, Did Methane addiction Set Off Earth's Greatest Ice Ages? Scientific America 16 Sept 2001 Scientific American Online.
Online 1 Apr 2003 Wikipedia, the free encyclopedia.
Snowball Earth 29 Sept. 2002.
Online. Wikipedia Internet 31 Mar 2002.