New research helps to identify ancient droughts in China

Mar 07, 2012

Drought events are largely unknown in Earth's history, because reconstruction of ancient hydrological conditions remains difficult due to lack of proxy. New GEOLOGY research supported by China's NNSF and MS&T uses a microbial lipid proxy of highly alkaline conditions to identify enhanced aridity in Miocene sediments on the Tibetan Plateau. This enhanced aridity is associated with significant uplift of the Tibetan Plateau nine million years ago.

According to the study's lead author, Xie Shucheng of the University of Geosciences at Wuhan, the identification of ancient droughts and associated alkaline soils is particularly challenging at the regional or local level, and is beyond the predictive capabilities of available general circulation models (GCMs). GCMs, which are used to understand physical processes in the surface system, are advanced tools for simulation of long-term temperature change.

This new research proposes a microbial lipid proxy of highly alkaline conditions and enhanced aridity on the basis of investigation of modern Chinese soils. In modern Chinese soils, more abundant archaeal lipids known as iGDGTs (isoprenoid glycerol dialkyl glycerol tetraethers) relative to bacterial branched GDGTs were found to be associated with alkaline conditions and enhanced aridity. As a consequence, the ratio of archaeal GDGTs to bacterial GDGTs is indicative of the occurrence of ancient alkalinity and enhanced aridity.

Xie and colleagues also used the microbial lipid proxy to identify the enhanced aridity and alkalinity of Late Miocene sediments from the Zhada basin, which is located in the southwestern Tibetan Plateau, ~1000 km west of Lhasa. They find that the highly alkaline conditions and enhanced aridity identified in these sediments are associated with the most significant uplift of the Tibetan Plateau nine million years ago. The study's findings suggest that abrupt uplifts in the Tibetan can cause enhanced aridity in central Asia and a consequential development of alkaline soils.

Explore further: NASA sees intensifying typhoon Phanfone heading toward Japan

More information: Microbial lipid records of highly alkaline deposits and enhanced aridity associated with significant uplift of the Tibetan Plateau in the Late Miocene; Shucheng Xie et al., State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China. Posted online 28 Feb. 2012; doi: 10.1130/G32570.1

Provided by Geological Society of America

5 /5 (2 votes)
add to favorites email to friend print save as pdf

Related Stories

Tibetan glaciers melting, says Dalai Lama

Apr 02, 2011

(AP) -- The Dalai Lama said Saturday that India should be seriously concerned about the melting of glaciers in the Tibetan plateau as millions of Indians use water that comes from there.

Geologists search for prehistoric high

Aug 20, 2007

Not all areas of the Tibetan Plateau rose at the same time, according to researchers who are determining the past elevation of plateau locations by studying the remains of terrestrial plants that once grew there.

Solving the mystery of the Tibetan Plateau

Nov 03, 2005

A University of Alberta physicist who helped solve the age-old mystery of what keeps afloat the highest plateau on earth has added more pieces to the Tibetan puzzle. Dr. Martyn Unsworth has uncovered new research about the ...

Recommended for you

Sculpting tropical peaks

14 hours ago

Tropical mountain ranges erode quickly, as heavy year-round rains feed raging rivers and trigger huge, fast-moving landslides. Rapid erosion produces rugged terrain, with steep rivers running through deep ...

Volcano expert comments on Japan eruption

15 hours ago

Loÿc Vanderkluysen, PhD, who recently joined Drexel as an assistant professor in Department of Biodiversity, Earth and Environmental Science in the College of Arts and Sciences, returned Friday from fieldwork ...

User comments : 0