Atmospheric composition and climate on the early Earth

被引:107
作者
Kasting, James F. [1 ]
Howard, M. Tazewell [1 ]
机构
[1] Penn State Univ, Dept Geosci, University Pk, PA 16802 USA
关键词
palaeoclimate; oxygen isotopes; sulphur isotopes; mass-independent fractionation; seawater composition;
D O I
10.1098/rstb.2006.1902
中图分类号
Q [生物科学];
学科分类号
07 ; 0710 ; 09 ;
摘要
Oxygen isotope data from ancient sedimentary rocks appear to suggest that the early Earth was significantly warmer than today, with estimates of surface temperatures between 45 and 85 degrees C. We argue, following others, that this interpretation is incorrect-the same data can be explained via a change in isotopic composition of seawater with time. These changes in the isotopic composition could result from an increase in mean depth of the mid-ocean ridges caused by a decrease in geothermal heat flow with time. All this implies that the early Earth was warm, not hot. A more temperate early Earth is also easier to reconcile with the long-term glacial record. However, what triggered these early glaciations is still under debate. The Paleoproterozoic glaciations at approximately 2.4 Ga were probably caused by the rise of atmospheric 02 and a concomitant decrease in greenhouse warming by CH4. Glaciation might have occurred in the Mid-Archaean as well, at approximately 2.9 Ga, perhaps as a consequence of anti-greenhouse cooling by hydrocarbon haze. Both glaciations are linked to decreases in the magnitude of mass-independent sulphur isotope fractionation in ancient rocks. Studying both the oxygen and sulphur isotopic records has thus proved useful in probing the composition of the early atmosphere.
引用
收藏
页码:1733 / 1741
页数:9
相关论文
共 82 条
[1]  
[Anonymous], THESIS J COOK U N QU
[2]  
[Anonymous], [No title captured]
[3]  
[Anonymous], SETTING STAGE EARLY
[4]   IMPACT MELTING OF FROZEN OCEANS ON THE EARLY EARTH - IMPLICATIONS FOR THE ORIGIN OF LIFE [J].
BADA, JL ;
BIGHAM, C ;
MILLER, SL .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1994, 91 (04) :1248-1250
[5]   THE CRITICAL-POINT AND 2-PHASE BOUNDARY OF SEAWATER, 200-500-DEGREES-C [J].
BISCHOFF, JL ;
ROSENBAUER, RJ .
EARTH AND PLANETARY SCIENCE LETTERS, 1984, 68 (01) :172-180
[7]   AN INTEGRATED CHEMICAL AND STABLE-ISOTOPE MODEL OF THE ORIGIN OF MIDOCEAN RIDGE HOT-SPRING SYSTEMS [J].
BOWERS, TS ;
TAYLOR, HP .
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH AND PLANETS, 1985, 90 (B14) :2583-2606
[8]  
BURDETT JW, 1990, GEOLOGY, V18, P227, DOI 10.1130/0091-7613(1990)018<0227:DMCITS>2.3.CO
[9]  
2
[10]  
Burke K.C., 1976, In the Early History of Earth, P113