Paleosol carbonate multiple isotopologue signature of active East Asian summer monsoons during the late Miocene and Pliocene

An Early Pleistocene atmospheric CO2 record based on pedogenic carbonate from the Chinese loess deposits

“…Previous studies provide some helpful information on the temperature variation of soil carbonate formation on the CLP. Suarez et al (2011) used the carbonate clumped isotope thermometer, with pedogenic carbonates collected in Lantian and Baode on the CLP, to reconstruct formation temperatures of samples found between 7-3 Myr. The resulting variations of temperatures from both localities are within 2 • C, suggesting small changes of nodule formation temperature over Miocene-Pliocene.…”

Climatic and tectonic controls on sedimentation and erosion during the Pliocene-Quaternary in the Qaidam Basin (China)

“…The change to a cooler (i.e., glacial or stadial) climate likely caused increased erosion, which resulted in the observed increase in sedimentation rates and grain size within many depocenters in central Asia (Métivier et al, 1999;Zhang et al, 2001). Alternatively, sedimentation rate and grain-size increases could also be caused by rapid uplift along the northern margin of the Tibet-Qinghai Plateau in the absence of precipitation changes (Sun and Liu, 2000;Zheng et al, 2000;Pares et al, 2003;Fang et al, 2007;Liu et al, 2010;Suarez et al, 2011). Orographic blocking by the Tibetan Plateau is widely regarded as the major forcing mechanism for the observed global climate change between 3.6 and 2.6 Ma (Ruddiman and Kutzbach, 1989;Raymo and Ruddiman, 1992;Hsu and Liu, 2003;Li et al, 2011;Kapp et al, 2011), although direct links between tectonic uplift and climate change remain debated (Molnar, 2005).…”

Small mammal tooth enamel carbon isotope record of C4 grasses in late Neogene China

“…Incidentally, a contemporaneous change in climatic regime is also observed on the Loess Plateau and Inner Mongolia. In Lingtai and Lantian, the δ 13 C sequences of pedogenic carbonate display a peak between 3.4 and 2.7 Ma (Ding and Yang, 2000;An et al, 2005;Kaakinen et al, 2006;Suarez et al, 2011) suggesting transient improved conditions for C 4 growth during that time. In Inner Mongolia moderate levels of C 4 grasses are still observed at 3.9 Ma in Gaotege, while presently, they account for an insignificant amount of the local biomass ) suggesting a retreat or at least a significant reduction of C 4 vegetation in the area.…”

“…Accumulating evidence from paleosol carbonate δ 13 C values from several localities in northern China (Ding and Yang, 2000;Jiang et al, 2002;An et al, 2005;Kaakinen et al, 2006;Passey et al, 2009;Suarez et al, 2011) indicates the presence of a spatial climatic gradient defined by northward increasing δ 13 C values and, thus, abundance of C 4 grasses, in the late Miocene and Pliocene (~7-2.7 Passey et al, 2009;Suarez et al, 2011) as a contrast to the late Pleistocene and present-day spatial pattern of southward increasing abundance of C 4 grass on the loess Plateau.…”

“…A subsequent weakening of the moisture-laden summer monsoons during 3.5-2.5 Ma caused a southward retreat of the forest-steppe-desert transition, moving the C 4 maximum steppe zone further away from the northern localities in Inner Mongolia, through the central and southern Loess Plateau localities Lingtai and Lantian. This shift might have been related to the establishment of the present state of focused summer rains with little spring, autumn, and winter precipitation (Suarez et al, 2011).…”