{"id":52779,"date":"2017-11-13T08:23:57","date_gmt":"2017-11-13T14:23:57","guid":{"rendered":"https:\/\/uwm.edu\/news\/?p=52779"},"modified":"2024-09-27T09:16:43","modified_gmt":"2024-09-27T14:16:43","slug":"uwm-geologists-uncover-antarcticas-fossil-forests","status":"publish","type":"post","link":"https:\/\/uwm.edu\/news\/uwm-geologists-uncover-antarcticas-fossil-forests\/","title":{"rendered":"51ÁÔÆæ geologists uncover Antarctica\u2019s fossil forests"},"content":{"rendered":"

During Antarctica\u2019s summer, from late November through January, UW-Milwaukee geologists Erik Gulbranson and John Isbell climbed the McIntyre Promontory\u2019s frozen slopes in the Transantarctic Mountains. High above the ice fields, they combed the mountain\u2019s gray rocks for fossils from the continent\u2019s green, forested past.<\/p>\n

By the trip\u2019s 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.<\/p>\n

\u201cPeople have known about the fossils in Antarctica since the 1910-12 Robert Falcon Scott expedition,\u201d said Gulbranson, a paleoecologist and visiting assistant professor in 51ÁÔÆæ\u2019s Department of Geosciences. \u201cHowever, most of Antarctica is still unexplored. Sometimes, you might be the first person to ever climb a particular mountain.\u201d<\/p>\n

The time frame is exactly what they are looking for. The Permian Period ended 251 million years ago in history\u2019s greatest mass extinction, as the Earth rapidly shifted from icehouse to greenhouse conditions. More than 90 percent of species on Earth disappeared, including the polar forests. Because the Antarctic forests grew at polar latitudes where plants\u00a0can\u2019t grow today, Gulbranson believes that the trees were an extremely hearty species\u00a0and is trying to determine why they went extinct.<\/p>\n

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Gulbranson studies a fossil under a microscope. (51ÁÔÆæ Photo\/Troye Fox)<\/figcaption><\/figure>\n

Many scientists now believe that a massive increase in atmospheric greenhouse gases, such as carbon dioxide and methane, caused the Permian-Triassic extinction. It\u2019s likely that over the course of 200,000 years \u2013 a short time, geologically speaking \u2013 volcanic eruptions in Siberia released many tons of greenhouse gases into the atmosphere.<\/p>\n

Isbell, a distinguished professor of geosciences at 51ÁÔÆæ, has previously studied Antarctica\u2019s Permian glacial deposits to determine how the climate changed. On this expedition, he used the rocks around the fossilized trees to determine how the fossils fit into Antarctica\u2019s geologic history.<\/p>\n

\u201cThis forest is a glimpse of life before the extinction, which can help us understand what caused the event,\u201d Gulbranson said. It can also give clues to how plants were different than today.<\/p>\n

\u00a0<\/strong>At the Permian Period\u2019s end, Antarctica was warmer and more humid than it is today. The world\u2019s continents, as we know them, were packed together in two giant landmasses \u2013 one in the north and one in the south. Antarctica was part of Gondwana, the supercontinent spanning the Southern Hemisphere that also included present-day South America, Africa, India, Australia and the Arabian Peninsula.<\/p>\n

There would have been a mixture of mosses, ferns and an extinct plant called Glossopteris<\/em>, and it\u2019s likely that this forest stretched across the entirety of Gondwana.<\/p>\n