Sat, Jul 12, 2014 - Page 4 News List

Rare plant fossil cluster found in south

By Chen Yen-ting and Jason Pan  /  Staff reporter, with staff writer

A plant fossil discovered on the Hengchun Peninsula, believed to be part of the nation’s most complete fossil cluster, is pictured next to a ruler in Pingtung County last week.

Photo courtesy of Li Ching-yao

Local researchers have discovered the nation’s most complete plant fossil cluster on the Hengchun Peninsula (恆春半島), providing scientific evidence that the area in southern Taiwan had a warm climate similar to the present when it was formed about 5 million years ago.

It was a rare find in Taiwan as the plant fossils were well-preserved in the sandstone strata, containing detailed imprints of leaves and seeds, said Li Ching-yao (李慶堯), an assistant professor at the Tungfang Design Institute in Greater Kaohsiung, who led the fossil search on the peninsula’s Lilong Mountain (里龍山).

Li said the mountain is the highest land mass in the peninsula and the region is a treasure trove for paleontologists and geologists.

A more than 10km area of Lilong and its offshoot, Wenjhao Mountain (蚊罩山), house the nation’s most complete and the widest outcrop exposure of plant fossils, he said.

“Plants, with their soft structures, are not easily preserved in fossil records, but harder seeds are more easily preserved,” Li said on Sunday of the team’s fossil find earlier this year. “Most of what we found were imprint fossils, where you can clearly see the shape and veins of the leaves.”

The team has so far collected 14 fossils of seeds, which have a thin film of carbon on the outside while their interior is filled with sandstone.

“As the internal structure was not preserved, I was able to identify only seven species from the seeds,” he said.

As for the imprint fossils of leaves, Li identified 23 species, some of which are still extant in Taiwan, including the camphor tree family, and the Fagaceae family of oak, chestnut and beech trees.

“Plant materials buried in rock strata can be fossilized as imprints only under abiotic conditions. The plant species found can be directly correlated with the prevailing climate at the time. This fossil group also contains a wide variety of plant species,” he added.

Li said that fossils record the rock strata’s geological age.

“From fossil dating, we can determine that the Hengchun Peninsula in the south rose above the sea in the late Miocene Epoch, or between 8.5 million to 5 million years ago,” he said.

Li has also found fossils of the Formosan gum tree, Asian melastome shrub and other plants in the Lilong Mountain area.

Using these fossils, together with those from the camphor tree and the Fagaceae family, he said that climate conditions were similar to the present time.

“We are looking to find more complete fossils of the original plant species to prove that plant growth was taking place. We will investigate further to gain a better understanding of the paleobotany and paleoclimate conditions,” Li said.

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