[meteorite-list] Oceanic and Atmospheric Cooling Started Before Start of Younger Dryas
From: Paul <etchplain_at_meteoritecentral.com>
Date: Fri, 15 Feb 2019 20:51:29 -0600 Message-ID: <2181d49a-6986-d339-5169-bb5dd7d8b1c0_at_att.net> Hi, While reading on a slow Friday afternoon, I came across the below paper. Levac, E., Sandercombe, S. and Chmura, G.L., 2018. The Younger Dryas in palynological records from the northern Northwest Atlantic: Does the terrestrial record lag the marine and air records?. Palaeogeography, Palaeoclimatology, Palaeoecology, ?490, pp.269-279. https://www.sciencedirect.com/science/article/pii/S0031018217307514 In part the the abstract states: ?Major changes in both pollen and dinocyst assemblages are recorded during the Younger Dryas in Bay of Islands and are associated with large drops in air and sea surface temperatures, and sea surface salinity. The changes in vegetation are similar with those observed at other sites in Newfoundland.? ?Sea-surface and air temperatures started cooling 250 and 110 years before the start of the YD, hence there is a 140 years delay between ocean and atmosphere.? On page 277 of Levac et al. (2018): ?However, we were not expecting a cooling trend (in sea-surface and air temperatures) that started before the recorded YD period.? and ?Not only did sea-surface and air temperatures start to deteriorate before the start of the YD (respectively 250 years and 110 years before the YD), we also see a 110 year-lag between the changes in air temperatures and pollen assemblages.? and ..and we suggest that the decrease in air temperatures in eastern Canada started before the YD period.? Basically, the cooling trend associated with the Younger Dryas (YD) actually started before the official start of the YD period, the time of the hypothesized YD impact. How can an extraterrestrial impact effect climate before it even happens? Yours, Paul H. Received on Fri 15 Feb 2019 09:51:29 PM PST |
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