Featured Research

from universities, journals, and other organizations

Dinosaurs' Climate Shifted Too, Reports Show

Date:
September 28, 2006
Source:
Indiana University
Summary:
Ancient rocks from the bottom of the Pacific Ocean suggest dramatic climate changes during the dinosaur-dominated Mesozoic Era, a time once thought to have been monotonously hot and humid.

U Bloomington geochemist Simon Brassell (right), Penn State sedimentologist Michael Arthur (middle), and Tohoku Univ. sedimentologist Harumasa Kano (left) inspect an ancient shale aboard the JOIDES Resolution research vessel.
Credit: Ocean Drilling Program

Ancient rocks from the bottom of the Pacific Ocean suggest dramatic climate changes during the dinosaur-dominated Mesozoic Era, a time once thought to have been monotonously hot and humid.

In this month's Geology, scientists from Indiana University Bloomington and the Royal Netherlands Institute for Sea Research present new evidence that ocean surface temperatures varied as much as 6 degrees Celsius (about 11 degrees Fahrenheit) during the Aptian Epoch of the Cretaceous Period 120 million years ago.

The finding is relevant to the ongoing climate change discussion, IUB geologist Simon Brassell says, because it portrays an ancient Earth whose temperatures shifted erratically due to changes in carbon cycling and did so without human input.

"Combined with data from the Atlantic, it appears clear that climate changes were taking place on a global scale during this time period," said Brassell, who led the study.

A previous study from an Atlantic Ocean site had suggested a changeable climate around the same time period. But it was not known whether the Atlantic data indicated regional climate change unique to the area or something grander.

"We had virtually no data from the middle of the largest ocean at that time period," Brassell said. "The data we collected suggest significant global fluctuations in temperature."

As part of the National Science Foundation's Ocean Drilling Project, the geoscientists voyaged in 2001 to Shatsky Rise, a study site 1,600 kilometers (1,000 miles) east of Japan and 3,100 meters below the ocean surface. Shatsky Rise is known to have formed at the end of the Jurassic Period immediately prior to the beginning of the Cretaceous, the last period of the Mesozoic Era.

The scientists' vessel, the JOIDES Resolution, is specially outfitted with a drill that can be lowered to the sea floor for the collection of rock samples.

The drill bit was driven 566 meters into Shatsky Rise. Rocks freed by the drill were transported directly to the surface for analysis. The rocks corresponding to early Aptian time were extremely rich in organic material. By analyzing the carbon and nitrogen content of the samples, the geochemists found evidence for changes in carbon cycling and in nitrogen fixation by ocean biological communities associated with changing climate. A special analysis method targeting certain complex carbon-containing molecules provided values for a measurement called TEX86 that revealed mean temperature variations between 30 deg C (86 deg F) and 36 deg C (97 deg F) with two prominent cooling episodes of approximately 4 deg C (7 deg F) in tropical surface temperatures during the early Aptian. By comparison, today's tropical sea surface temperatures typically lie between 29 and 30 deg C.

Brassell says that findings of a changeable climate during the Cretaceous, a time period dominated by dinosaurs and noted for the spread of flowering plants, could influence the current climate change debate.

"One of the key challenges for us is trying to predict climate change," Brassell said. "If there are big, inherent fluctuations in the system, as paleoclimate studies are showing, it could make determining Earth's climatic future even harder than it is. We're learning our climate, throughout time, has been a wild beast."

IU Bloomington Geological Sciences graduate student Mirela Dumitrescu and Royal Netherlands Institute for Sea Research scientists Stefan Schouten, Ellen Hopmans and Jaap Sinninghe Damstι also contributed to the report. It was funded with grants from the Geological Society of America and the IU Bloomington Department of Geological Sciences, with ongoing research support from the National Science Foundation, the United States Science Advisory Committee, and the American Chemical Society. A related paper by Mirela Dumitrescu and Simon Brassell recently won the 2006 Best Paper Award from the Organic Geochemistry Division of the Geochemical Society.

More information about the Ocean Drilling Program can be found at http://www.oceandrilling.org/.


Story Source:

The above story is based on materials provided by Indiana University. Note: Materials may be edited for content and length.


Cite This Page:

Indiana University. "Dinosaurs' Climate Shifted Too, Reports Show." ScienceDaily. ScienceDaily, 28 September 2006. <www.sciencedaily.com/releases/2006/09/060923104311.htm>.
Indiana University. (2006, September 28). Dinosaurs' Climate Shifted Too, Reports Show. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2006/09/060923104311.htm
Indiana University. "Dinosaurs' Climate Shifted Too, Reports Show." ScienceDaily. www.sciencedaily.com/releases/2006/09/060923104311.htm (accessed September 1, 2014).

Share This




More Earth & Climate News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Washington Wildlife Center Goes Nuts Over Baby Squirrels

Washington Wildlife Center Goes Nuts Over Baby Squirrels

Reuters - US Online Video (Aug. 30, 2014) — An animal rescue in Washington state receives an influx of orphaned squirrels, keeping workers busy as they nurse them back to health. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Raw: Volcano Erupts on Papua New Guinea

Raw: Volcano Erupts on Papua New Guinea

AP (Aug. 29, 2014) — Several communities were evacuated and some international flights were diverted on Friday after one of the most active volcanos in the region erupts. (Aug. 29) Video provided by AP
Powered by NewsLook.com
Raw: Small Volcanic Eruption in Iceland

Raw: Small Volcanic Eruption in Iceland

AP (Aug. 29, 2014) — Icelandic authorities briefly raised the aviation warning code to red on Friday during a small eruption at the Holuhraun lava field in the Bardabunga volcano system. (Aug. 29) Video provided by AP
Powered by NewsLook.com
As Drought Continues LA "water Police" Fight Waste

As Drought Continues LA "water Police" Fight Waste

AFP (Aug. 29, 2014) — In the midst of a historic drought, Los Angeles is increasing efforts to go after people who waste water. Five water conservation "cops" drive around the city every day educating homeowners about the drought. Duration: 02:17 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins