Floor of Oldest Fossilized Forest Discovered: 385 Million Years Old
ScienceDaily (Mar. 1, 2012) — Scientists from Binghamton University and Cardiff University, and New York State Museum researchers, and have reported the discovery of the floor of the world’s oldest forest in a cover article in the March 1 issue of Nature.
“It was like discovering the botanical equivalent of dinosaur footprints,” said Dr. William Stein, associate professor of biological sciences at Binghamton University, and one of the article’s authors. “But the most exciting part was finding out just how many different types of footprints there were. The newly uncovered area was preserved in such a way that we were literally able to walk among the trees, noting what kind they were, where they had stood and how big they had grown.”
Scientists are now piecing together a view of this ancient site, dating back about 385 million years ago, which could shed new light on the role of modern-day forests and their impact on climate change.
The recent discovery was made in the same area in Schoharie County where fossils of Earth’s oldest trees — the Gilboa stumps — were discovered in the 1850s, 1920 and again in 2010 and were brought to the State Museum. The Museum has the world’s largest and best collection of Gilboa fossil tree stumps. For decades scientists did not know what the trees connected to the stumps looked like. That mystery was solved when Linda VanAller Hernick, the State Museum’s Paleontology collections manager, and Frank Mannolini, Paleontology collections technician, found fossils of the tree’s intact crown in a nearby location in 2004, and a 28-foot-long trunk portion in 2005. Mannolini, Hernick, and Dr. Christopher M. Berry, a paleobotany lecturer at Cardiff University in Wales, co-authored a Nature article reporting that discovery, as well as the most recent one. Working in conjunction with Stein, Mannolini also developed a sketch of the ancient forest.
“This spectacular discovery and the resulting research provide more answers to the questions that have plagued scientists for more than a century since the first Gilboa stumps were uncovered and brought to the State Museum,” said Hernick, whose passionate interest in the fossils date back to her childhood exposure to the Gilboa fossils. In 2003 Hernick wrote The Gilboa Fossils, a book published by the State Museum, about the history and significance of the fossils and their use in an iconic exhibition about the Earth’s oldest forest that was in the Museum’s former location in the State Education Department building on Washington Avenue. One of the key planners of the exhibition, which influenced generations of paleontologists, was Winifred Goldring, the nation’s first female state paleontologist who was based at the State Museum. She worked tirelessly to study and interpret the Gilboa fossils and named the trees Eospermatopteris, or “ancient seed fern.” In 1924, her paper about the stumps, together with the Museum exhibition, brought the “Gilboa forest” to the attention of the world. One of the Gilboa stumps will be on display in the Museum lobby, beginning March 2. Following the discovery of the tree’s crown, a thorough investigation was conducted by Stein and Dr. Christopher M. Berry, a paleobotany lecturer at Cardiff University in Wales and the other co-author of both Nature articles. They were able to determine that these trees actually resembled modern-day cycads or tree ferns, but interestingly enough, were not related to either one. Many questions still remained about what the surrounding area looked like, whether other plant life co-existed with these trees and how.
In 2010, during ongoing repair of the Gilboa Dam, New York City Department of Environmental Protection (DEP) engineers excavated infill from a quarry in Schoharie County. They agreed to allow researchers to re-examine the site where the fossils had been found when the dam was built in the 1920s. What they found this time was a large, substantially intact portion of the ancient forest horizon, complete with root systems. As they had expected, Eospermatopteris root systems of different sizes were the most abundant. But what they didn’t expect to find was the level of detail of the overall composition of the forest.
The first glimpse of the unexpected complexity of this ancient forest came when Stein, Berry, Hernick and Mannolini found the remains of large scrambling tree-sized plants, identified as aneurophytaleans. These plants were likely close ecological associates to the original trees, living among them on the forest floor like modern ferns, possibly scrambling into the forest canopy much as tropical vines do today. The aneurophytes are the first in the fossil record to show true “wood” and the oldest known group in the lineage that lead to modern seed plants.
Work on the new discoveries also pointed to the vital importance that the State Museum’s collections have played in the paleontological research. “Discovery of scrambling aneurophytaleans at Gilboa was a complete surprise, but pointed to the likelihood that similar material had already been found at the site, but was unrecognized,” said Hernick. “Sure enough in the State Museum collections a wonderful specimen, originally collected in the 1920s, provided additional key evidence.”
The team also came across a tree belonging to the class Lycopsida, or club mosses, which predates an earlier discovery made in Naples, NY and an ecologically important group in the history of land plants. The lycopsids are an ancient group of non-seed plants represented today by low growing forms such as the “running pines” of the northern hardwood forests of New York. They also inhabited swamps and ended up being much of the Pennsylvanian coal we burn today.
Based on the new research, the team now believes that the area probably enjoyed a wetland environment in a tropical climate. It was filled with large Eospermatopteris trees that resembled weedy, hollow, bamboo-like plants, with roots spreading out in all directions, allowing other plants to gain a foothold. Scrambling among these roots on the forest floor were aneurophytaleans, acting much like ferns do today, and possibly climbing into the forest canopy as vines. The lycopsids, although seemingly rare, may also have been very important in certain places although perhaps not yet as specialized inhabitants of swamps.
But what the research team believes is most important about this particular site is what it was doing to impact the rest of the planet. At the time the Gilboa forest began to emerge — during the Middle Devonian period, about 385 million years ago — Earth experienced a dramatic drop in global atmospheric carbon dioxide levels and the associated cooling led ultimately to a period of glaciation.
“Trees probably changed everything,” said Stein. “Not only did these emerging forests likely cause important changes in global patterns of sedimentation, but they may have triggered a major extinction in fossil record.”
For Stein, it all comes down to one thing — how much we don’t know but need to understand about our ancient past. “The complexity of the Gilboa site can teach us a lot about the original assembly of our modern day ecosystems,” said Stein. “As we continue to understand the role of forests in modern global systems, and face potential climate change and deforestation on a global scale, these clues from the past may offer valuable lessons for managing our planet’s future.”
300-Million-Year-Old Forest Discovered Preserved in Volanic Ash
ScienceDaily (Feb. 20, 2012) — Pompeii-like, a 300-million-year-old tropical forest was preserved in ash when a volcano erupted in what is today northern China. A new study by University of Pennsylvania paleobotanist Hermann Pfefferkorn and colleagues presents a reconstruction of this fossilized forest, lending insight into the ecology and climate of its time.
Pfefferkorn, a professor in Penn’s Department of Earth and Environmental Science, collaborated on the work with three Chinese colleagues: Jun Wang of the Chinese Academy of Sciences, Yi Zhang of Shenyang Normal University and Zhuo Feng of Yunnan University.
Their paper was published this week in the Early Edition of the Proceedings of the National Academy of Sciences.
The study site, located near Wuda, China, is unique as it gives a snapshot of a moment in time. Because volcanic ash covered a large expanse of forest in the course of only a few days, the plants were preserved as they fell, in many cases in the exact locations where they grew.
“It’s marvelously preserved,” Pfefferkorn said. “We can stand there and find a branch with the leaves attached, and then we find the next branch and the next branch and the next branch. And then we find the stump from the same tree. That’s really exciting.”
The researchers also found some smaller trees with leaves, branches, trunk and cones intact, preserved in their entirety.
Due to nearby coal-mining activities unearthing large tracts of rock, the size of the researchers’ study plots is also unusual. They were able to examine a total of 1,000 m2 of the ash layer in three different sites located near one another, an area considered large enough to meaningfully characterize the local paleoecology.
The fact that the coal beds exist is a legacy of the ancient forests, which were peat-depositing tropical forests. The peat beds, pressurized over time, transformed into the coal deposits.
The scientists were able to date the ash layer to approximately 298 million years ago. That falls at the beginning of a geologic period called the Permian, during which Earth’s continental plates were still moving toward each other to form the supercontinent Pangea. North America and Europe were fused together, and China existed as two smaller continents. All overlapped the equator and thus had tropical climates.
At that time, Earth’s climate was comparable to what it is today, making it of interest to researchers like Pfefferkorn who look at ancient climate patterns to help understand contemporary climate variations.
In each of the three study sites, Pfefferkorn and collaborators counted and mapped the fossilized plants they encountered.In all, they identified six groups of trees. Tree ferns formed a lower canopy while much taller trees — Sigillaria and Cordaites — soared to 80 feet above the ground. The researchers also found nearly complete specimens of a group of trees called Noeggerathiales. These extinct spore-bearing trees, relatives of ferns, had been identified from sites in North America and Europe but appeared to be much more common in these Asian sites.
They also observed that the three sites were somewhat different from one another in plant composition. In one site, for example, Noeggerathiales were fairly uncommon, while they made up the dominant plant type in another site. The researchers worked with painter Ren Yugao to depict accurate reconstructions of all three sites.
“This is now the baseline,” Pfefferkorn said. “Any other finds, which are normally much less complete, have to be evaluated based on what we determined here.”
The findings are indeed “firsts” on many counts.
“This is the first such forest reconstruction in Asia for any time interval, it’s the first of a peat forest for this time interval and it’s the first with Noeggerathiales as a dominant group,” Pfefferkorn said.
Because the site captures just one moment in Earth’s history, Pfefferkorn noted that it alone cannot explain how climate changes affected life on Earth. But it helps provide valuable context.
“It’s like Pompeii: Pompeii gives us deep insight into Roman culture, but it doesn’t say anything about Roman history in and of itself,” Pfefferkorn said. “But on the other hand, it elucidates the time before and the time after. This finding is similar. It’s a time capsule and therefore it allows us now to interpret what happened before or after much better.”
The study was supported by the Chinese Academy of Science, the National Basic Research Program of China, the National Natural Science Foundation of China and the University of Pennsylvania.
University of Pennsylvania (2012, February 20). 300-million-year-old forest discovered preserved
Central Africa’s Tropical Congo Basin Was Arid, Treeless In Late Jurassic
The Congo Basin — with its massive, lush tropical rain forest — was far different 150 million to 200 million years ago. At that time Africa and South America were part of the single continent Gondwana. The Congo Basin was arid, with a small amount of seasonal rainfall, and few bushes or trees populated the landscape, according to a new geochemical analysis of rare ancient soils.
The geochemical analysis provides new data for the Jurassic period, when very little is known about Central Africa’s paleoclimate, says Timothy S. Myers, a paleontology doctoral student in the Roy M. Huffington Department of Earth Sciences at Southern Methodist University in Dallas.
“There aren’t a whole lot of terrestrial deposits from that time period preserved in Central Africa,” Myers says. “Scientists have been looking at Africa’s paleoclimate for some time, but data from this time period is unique.”
There are several reasons for the scarcity of deposits: Ongoing armed conflict makes it difficult and challenging to retrieve them; and the thick vegetation, a humid climate and continual erosion prevent the preservation of ancient deposits, which would safeguard clues to Africa’s paleoclimate.
Myers’ research is based on a core sample drilled by a syndicate interested in the oil and mineral deposits in the Congo Basin. Myers accessed the sample — drilled from a depth of more than 2 kilometers — from the Royal Museum for Central Africa in Tervuren, Belgium, where it is housed. With the permission of the museum, he analyzed pieces of the core at the SMU Huffington Department of Earth Sciences Isotope Laboratory.
“I would love to look at an outcrop in the Congo,” Myers says, “but I was happy to be able to do this.”
The Samba borehole, as it’s known, was drilled near the center of the Congo Basin. The Congo Basin today is a closed canopy tropical forest — the world’s second largest after the Amazon. It’s home to elephants, great apes, many species of birds and mammals, as well as the Congo River. Myers’ results are consistent with data from other low paleolatitude, continental, Upper Jurassic deposits in Africa and with regional projections of paleoclimate generated by general circulation models, he says.
“It provides a good context for the vertebrate fossils found in Central Africa,” Myers says. “At times, any indications of the paleoclimate are listed as an afterthought, because climate is more abstract. But it’s important because it yields data about the ecological conditions. Climate determines the plant communities, and not just how many, but also the diversity of plants.”
While there was no evidence of terrestrial vertebrates in the deposits that Myers studied, dinosaurs were present in Africa at the same time. Their fossils appear in places that were once closer to the coast, he says, and probably wetter and more hospitable.
The Belgium samples yielded good evidence of the paleoclimate. Myers found minerals indicative of an extremely arid climate typical of a marshy, saline environment. With the Congo Basin at the center of Gondwana, humid marine air from the coasts would have lost much of its moisture content by the time it reached the interior of the massive continent.
“There probably wouldn’t have been a whole lot of trees; more scrubby kinds of plants,” Myers says.
The clay minerals that form in soils have an isotopic composition related to that of the local rainfall and shallow groundwater. The difference in isotopic composition between these waters and the clay minerals is a function of surface temperature, he says. By measuring the oxygen and hydrogen isotopic values of the clays in the soils, researchers can estimate the temperature at which the clays formed.
Myers presented his research, “Late Jurassic Paleoclimate of Central Africa,” at a scientific session of the 2009 annual meeting of The Geological Society of America in Portland, Ore., Oct. 18-21.
The research was funded by the Roy M. Huffington Department of Earth Sciences at SMU, and the Institute for the Study of Earth and Man at SMU.
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