City-sized fossilized forest found
Apr 27,2007 00:00 by Bend_Weekly_News_Sources

Re­search­ers have found a cit­y-sized fos­sil­ized for­est in an Il­li­nois coal mine, and they say it trans­forms our un­der­stand­ing of the Earth’s first rain­for­ests.

No­where else, sci­en­tists say, can one lit­er­al­ly walk through such a huge swath of rain­for­est from the Car­bon­if­er­ous era. That was a time 360 mil­lion to 290 mil­lion years ago when true rep­tiles ap­peared, gi­ant dra­gon­flies buzzed and vast swamps spread, which lat­er formed coal.

De­tail of a pter­i­do­sperm, an ex­tinct seed-pro­duc­ing fern-like plant. The im­age shows an area about six cm (2.4 inch­es) in height. (Cour­te­sy How­ard Fal­con-Lang)

Mod­ern club moss. Its an­ces­tors reached the height of trees dur­ing the Car­bon­if­er­ous. (Cour­te­sy Na­tion­al Park Serv­ice)

A huge earth­quake 300 mil­lion years ago caused the whole re­gion around this for­est to col­lapse be­low sea lev­el, ac­cord­ing to the sci­en­tists. Mud then bur­ied the ter­rain and pre­served it for­ev­er.

The for­est offers a bi­zarre med­ley of ex­tinct plants. They in­clude plen­ti­ful club mosses, or pri­mi­tive moss-like plants, more than 40 me­tres (131 feet) high. These tow­ered over mixes of tree ferns, shrubs and tree-sized horse­tails.

The for­est was found by How­ard Falcon-Lang of the Uni­ver­si­ty of Bris­tol, U.K., and U.S. col­leagues. The find­ings are pub­lished on­line Ap­ril 23 in the re­search jour­nal Ge­ol­o­gy.

“It was an amaz­ing ex­pe­ri­ence. We drove down the mine in an ar­moured ve­hi­cle un­til we were a hun­d­red me­tres” or 109 yards un­der­ground, Fal­con-Lang said. 

The for­est was root­ed a­top the coal bed, “so where the coal had been mined away the fos­sil­ized for­est was vis­i­ble in the ceil­ing of the mine,” he added.

“We walked for miles and miles along pitch-black pas­sages with the fos­sil for­est just above our heads. We were able to make a map of the for­est by the light of our min­er’s lamps.”

The larg­est fos­sil for­est known, it co­vers an ar­ea 10 km by 10 km (six miles by six miles), he said. This would co­ver the city of Bris­tol, U.K. The fos­sils pre­serve a unique snap­shot of what trop­i­cal rain­for­ests were like 300 mil­lion year ago, he re­marked.

“As there is noth­ing like it around to­day, be­fore our work we knew very lit­tle about the ec­o­log­i­cal pref­er­ences and com­mu­ni­ty struc­ture of these an­cient plants,” Fal­con-Lang said. 

“This spec­tac­u­lar disco­very al­lows us to track how the spe­cies make-up of the for­est changed across the land­scape, and how that spe­cies make-up is af­fect­ed by sub­tle dif­fer­ences in the lo­cal en­vi­ron­ment.”

The study re­con­structs a Car­bon­if­er­ous rain­for­est on the larg­est scale ev­er at­tempted. The fos­sils show that the Earth’s first rain­for­ests were high­ly di­verse and that the types of trees changed across the an­cient land­scape, he said.

Courtesy ESO and World Science staff