Professor Jane Francis from Leeds University gave a talk at the SCAR 2012 Open Science Conference on sea ice during the Cretaceous period.
During the Cretaceous (approximately 70 million years ago), the Antarctic continent was much warmer than today, with forests on Seymour Island. Dinosaurs stalked the land and huge sharks lived in the ocean. The ammonites and marine fossils that are now abundant on James Ross Island were swimming around. However, large sea level jumps of up to 25 m have been observed in New Jersey, suggesting that at this time, small ice caps were in existence, causing eustatic sea level fall. However, the evidence for glaciers and ice caps in polar regions is sparse.
Professor Francis demonstrated that the extensive sedimentary outcrops on Seymour Island held many well-preserved marine microfossils, but that there was no clear, comprehensive evidence for climate change. However, she presented evidence of new marine dinoflagellate cysts that could have lived in sea ice, suggesting periodic colder periods. Small glaciers and ice caps may have persisted on the Antarctic Peninsula mountains during this time.
Profesa Jane Francis wa Chuo Kikuu cha Leeds, Uingereza, alitoa hotuba katika mkutano wa sayansi ya wazi wa SCAR 2012 kuhusu barafu ya bahari wakati wa kipindi cha Cretaceous. Katika kipindi cha Cretaceous (karibu miaka milioni 70 iliyopita), bara la Antaktika lilikuwa na joto zaidi kuliko leo, na misitu ilikuwa kwenye Kisiwa cha Seymour. Dinosaur waliishi kwenye nchi kavu na papa wakubwa waliishi baharini. Ammoni na visukuku vya baharini ambavyo sasa viko kwa wingi kwenye Kisiwa cha James Ross vilikuwa vikisafiri. Hata hivyo, ongezeko kubwa la kiwango cha bahari la hadi mita 25 limegunduliwa katika New Jersey, ikidokeza kwamba wakati huo, barafu ndogo zilikuwa zipo, zikisababisha kupungua kwa kiwango cha bahari. Hata hivyo, kuna uthibitisho mdogo wa kuwapo kwa barafu na barafu katika maeneo ya barafu. Profesa Francis alionyesha kwamba mabaki makubwa ya sedimentary kwenye Kisiwa cha Seymour yalikuwa na viumbe wengi wa baharini waliohifadhiwa vizuri, lakini kwamba hakukuwa na ushahidi wa wazi, wa kina wa mabadiliko ya hali ya hewa. Hata hivyo, alitoa ushahidi wa chembe mpya za dinoflagellate za baharini ambazo zingeweza kuishi katika barafu ya bahari, ikidokeza vipindi vya baridi zaidi. Huenda barafu ndogo-ndogo na vigae vya barafu viliendelea kuwapo kwenye milima ya Peninsula ya Antaktika wakati huo.