Ancient wood points to Arctic greenhouse. (Paleobiology).Chemical analyses of wood that grew in an ancient arctic forest suggest that the air there once was about twice as humid as it is now. About 45 million years ago, forests of redwoods grew on what is now Axel Heiberg Island Axel Heiberg Island (ăk`səl hī`bərg), 13,583 sq mi (35,180 sq km), in the Arctic Ocean, N Nunavut Territory, Canada, W of Ellesmere Island. , a Maryland-size landmass land·mass n. A large unbroken area of land. landmass Noun a large continuous area of land landmass Off the northern coast of Canada. At some sites, wood from those trees is exquisitely preserved, apparently changed only by desiccation des·ic·ca·tion n. The process of being desiccated. des  ic·ca and slight compression by surrounding sediments. "It's like driftwood," says A. Hope Jahren, a geochemist at Johns Hopkins University Johns Hopkins University, mainly at Baltimore, Md. Johns Hopkins in 1867 had a group of his associates incorporated as the trustees of a university and a hospital, endowing each with $3.5 million. Daniel C. in Baltimore. By analyzing the ratios of oxygen isotopes and hydrogen isotopes in the wood's cellulose, Jahren and Leonel S.L. Sternberg of the University of Miami This article is about the university in Coral Gables, Florida. For the university in Oxford, Ohio, see Miami University. The University of Miami (also known as Miami of Florida,[2] UM,[3] or just The U could estimate how humid the ancient forest was. On average, they report in the May Geology, the forest's atmosphere held about twice the water vapor found in the region today. The extra humidity would have provided a vital greenhouse effect, trapping outbound heat radiating from the ground during winter periods marked by 24-hour-a-day darkness. Isotope ratios in a carbonate mineral infiltrating other wood samples suggest the region's average annual temperature 45 million years ago was about 13[degrees]C, says Jahren. Overall, these environmental conditions match the springtime climate in today's coastal forests of Oregon.--S.P. |
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