K-T event

greenspun.com : LUSENET : Introductory Geology, Oswego State : One Thread

Ice ages can occur because the earth undergoes a different orbit; however, when the K-T mass extinction event occured earth went through a different ice age. Why and how?

-- Jason Kim (tkd4j@yahoo.com), November 17, 2002


I have a feeling that i can recall a possible suggestion as to the cause of the "ice age" you mention - if i can recall it from the depths of my mind. Whilst it offers a possible method, how accurate or true to life it is i do not know. i cant substantiate it in any way, but it has been given to me as a "consequence" of impacts whilst researching a project last year. the KT event is thought to have been caused 63.5Ma by an impact at Chicxulub on the Yucatan peninsula (coast of mexico).

i am a geology student at University of Bristol, UK. i recall that in some lectures i heard mention of how global warming can lead to increased precipitation (ppt). increase ppt means increased ppt all over earth, not in restricted areas. this means that more precipitation will occur at the poles. if this occurs, then the additional snow falling at the poles could enlarge the icecaps, despite the increased global temp increasing melt rate of ice caps.

I recall the suggestion that a large scale impact such as that at chicxulub, would suspend fine debris in the atmosphere for a prelonged period. this would block sunlight and trap heat. the lack of sunlight leads to a loss of plant life. no plants = no photosynthesis = CO2 build up = global warming = more rain = ice caps grow = global cooling. it was even suggested to me that the decaying corpses of dinosaurs and decaying plant matter was on a sufficiently large scale as to contribute green house gases such as methane to the atmosphere

as i say, this is a schematic idea of how a meteorite impact causing the KT event could lead to global cooling. i have no evidence, just background research and assimilation of ideas. however, i do not recall hearing before that following the KT event there was an ice age. you should also remember that some of the extinction occuring at the Kt event could be due to falling temperatures and that "ice age" you mention is not thought, as far as i am aware, to be the cause of the KT mass extinction.

i hope that this information is useful to you, but i suspect that it wont be as the initial question is dated november 2002

-- Paul Freeman (gingerpaul@hotmail.com), February 04, 2003.

Moderation questions? read the FAQ