Details

Autor(en) / Beteiligte

• Herman, Alexei B.
• Spicer, Robert A.
• Aleksandrova, Galina N.
• Yang, Jian
• Kodrul, Tatiana M.
• Maslova, Natalia P.
• Spicer, Teresa E.V.
• Chen, Gang
• Jin, Jian-Hua

Titel

Eocene–early Oligocene climate and vegetation change in southern China: Evidence from the Maoming Basin

Ist Teil von

• Palaeogeography, palaeoclimatology, palaeoecology, 2017-08, Vol.479, p.126-137

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2017

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Although the Eocene-Oligocene climate transition marks a critical point in the development of the ‘icehouse’ global climate of the present little is known about this important change in the terrestrial realm at low latitudes. Our palynological study of the Shangcun Formation shows it to be early Oligocene in age: palyno-assemblages in the lower part of the formation indicate a cool interval dominated by conifer pollen in the earliest Oligocene followed by a warmer regime in the second half of the early Oligocene. To quantify middle Eocene to late early Oligocene climate conditions at low (~20°N) palaeolatitudes in southern Asia several thousand leaf fossil specimens from the Maoming Basin, southern China, were subjected to a multivariate (CLAMP) analysis of leaf form. For terrestrial palaeoclimate comparisons to be valid the palaeoaltitude at which the proxy data are obtained must be known. We find that leaves preserved in the Youganwo (middle Eocene), Huangniuling (late Eocene) and Shangcun (early Oligocene) formations were likely to have been deposited well above sea level at different palaeoelevations. In the Youganwo Formation fine-grained sediments were deposited at an altitude of ~1.5km, after which the basin dropped to ~0.5km by the time the upper Huangniuling sediments were deposited. The basin floor then rose again by 0.5km reaching an altitude of approximately 1km in which the Shangcun Formation fine-grained sediments were accumulated. Within the context of these elevation changes the prevailing climates experienced by the Youganwo, Lower Huangniuling, Upper Huangniuling and Shangcun fossil floras were humid subtropical with hot summers and warm winters, but witnessed a progressive increase in rainfall seasonality. By the early Oligocene rainfall seasonality was similar to that of the modern monsoonal climate of Guangdong Province, southern China. All floras show leaf physiognomic spectra most similar to those growing under the influence of the modern Indonesia-Australia Monsoon, but with no evidence of any adaptation to today's South or East Asia Monsoon regimes. The Upper Huangniuling Flora, rich in dipterocarp plant megafossils, grew in the warmest conditions with the highest cold month mean temperature and at the lowest altitude. •Eocene and Oligocene plant fossils from southern China were subjected to a multivariate analysis of leaf form.•Using CLAMP technique, we estimated that leaves were deposited at different palaeoelevations.•The prevailing climates experienced by the fossil floras were humid subtropical with hot summers and warm winters.•During middle Eocene–early Oligocene a progressive increase in rainfall seasonality is observed.•By the early Oligocene rainfall seasonality was similar to that of the modern monsoonal climate of southern China.