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Wednesday, November 15, 2017

Forests in the Transantarctic Mountains


Researchers have identified two distinct environments at the South Pole at the close of the Permian Period. There was a warm rainforest with tree-ferns, palm trees and baobab trees at the lower elevations, and a cooler mountainous region dominated by beech trees and conifers.



Fossil tree trunk in what was an ancient polar forest
Credit: Erik Gulbranson


During Antarctica's summer, from late November through January, UW-Milwaukee geologists Erik Gulbranson and John Isbell climbed the McIntyre Promontory's frozen slopes in the Transantarctic Mountains. High above the ice fields, they combed the mountain's gray rocks for fossils from the continent's green, forested past.

By the trip's end, the geologists had found fossil fragments of 13 trees. The discovered fossils reveal that the trees are over 260 million years old, meaning that this forest grew at the end of the Permian Period, before the first dinosaurs, when Antarctica was still at the South Pole.

At the Permian Period's end, Antarctica was warmer and more humid than it is today. 

By studying the preserved tree rings, Gulbranson and colleagues have found that these trees transitioned from summer activity to winter dormancy rapidly, perhaps within a month

Read more here



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