TY  - JOUR
A1  - Zhang Chengjun, 
A1  - Fan Rong, 
A1  - Li Jun, 
A1  - Mischke, Steffen
A1  - Dembele, Blaise
A1  - Hu Xiaolan, 
T1  - Carbon and oxygen isotopic compositions - how lacustrine environmental factors respond in northwestern and northeastern China
JF  - Acta geologica Sinica : english edition
N2  - Surface lake sediments, 28 from Hoh Xil, 24 from northeastern China, 99 from Lake Bosten, 31 from Ulungur and 26 from Heihai were collected to determine C-13 and O-18 values. Considering the impact factors, conductivity, alkalinity, pH, TOC, C/N and carbonate-content in the sediments, Cl, P, S, and metal element ratios of Mg/Ca, Sr/Ca, Fe/Mn of bulk sediments as environmental variables enable evaluation of their influences on C-13 and O-18 using principal component analysis (PCA) method. The closure and residence time of lakes can influence the correlation between C-13 and O-18. Lake water will change from fresh to brackish with increasing reduction and eutrophication effects. Mg/Ca in the bulk sediment indicates the characteristic of residence time, Sr/Ca and Fe/Mn infer the salinity of lakes. Carbonate formation processes and types can influence the C-13-O-18 correlation. O-18 will be heavier from Mg-calcite and aragonite formed in a high-salinity water body than calcite formed in freshwater conditions. When carbonate content is less than 30%, there is no relationship with either C-13 or O-18, and also none between C-13 and O-18. More than 30%, carbonate content, however, co-varies highly to C-13 and O-18, and there is also a high correlation between C-13 and O-18. Vegetation conditions and primary productivity of lakes can influence the characteristics of C-13 and O-18, and their co-variance. Total organic matter content (TOC) in the sediments is higher with more terrestrial and submerged plants infilling. In northeastern and northwestern China, when organic matter in the lake sediments comes from endogenous floating organisms and algae, the C-13 value is high. C-13 is in the range of -4%o to 0 parts per thousand when organic matter comes mainly from floating organisms (C/N<6); in the range of -4 parts per thousand to 8 parts per thousand when organic matter comes from diatoms (C/N=6 to 8); and -8 parts per thousand to -4 parts per thousand when organic matter comes from aquatic and terrestrial plants (C/N>8).
KW  - Limnology
KW  - isotopic analysis
KW  - carbonates
KW  - organic matter
KW  - PCA
KW  - Tibet
KW  - Xinjiang
KW  - Northeastern China
Y1  - 2013
U6  - https://doi.org/10.1111/1755-6724.12133
SN  - 1000-9515
SN  - 1755-6724
VL  - 87
IS  - 5
SP  - 1344
EP  - 1354
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Foerster, Verena
A1  - Asrat, Asfawossen
A1  - Ramsey, Christopher Bronk
A1  - Brown, Erik T.
A1  - Chapot, Melissa S.
A1  - Deino, Alan
A1  - Düsing, Walter
A1  - Grove, Matthew
A1  - Hahn, Annette
A1  - Junginger, Annett
A1  - Kaboth-Bahr, Stefanie
A1  - Lane, Christine S.
A1  - Opitz, Stephan
A1  - Noren, Anders
A1  - Roberts, Helen M.
A1  - Stockhecke, Mona
A1  - Tiedemann, Ralph
A1  - Vidal, Celine M.
A1  - Vogelsang, Ralf
A1  - Cohen, Andrew S.
A1  - Lamb, Henry F.
A1  - Schaebitz, Frank
A1  - Trauth, Martin H.
T1  - Pleistocene climate variability in eastern Africa influenced hominin evolution
JF  - Nature geoscience
N2  - Despite more than half a century of hominin fossil discoveries in eastern Africa, the regional environmental context of hominin evolution and dispersal is not well established due to the lack of continuous palaeoenvironmental records from one of the proven habitats of early human populations, particularly for the Pleistocene epoch. Here we present a 620,000-year environmental record from Chew Bahir, southern Ethiopia, which is proximal to key fossil sites. Our record documents the potential influence of different episodes of climatic variability on hominin biological and cultural transformation. The appearance of high anatomical diversity in hominin groups coincides with long-lasting and relatively stable humid conditions from similar to 620,000 to 275,000 years bp (episodes 1-6), interrupted by several abrupt and extreme hydroclimate perturbations. A pattern of pronounced climatic cyclicity transformed habitats during episodes 7-9 (similar to 275,000-60,000 years bp), a crucial phase encompassing the gradual transition from Acheulean to Middle Stone Age technologies, the emergence of Homo sapiens in eastern Africa and key human social and cultural innovations. Those accumulative innovations plus the alignment of humid pulses between northeastern Africa and the eastern Mediterranean during high-frequency climate oscillations of episodes 10-12 (similar to 60,000-10,000 years bp) could have facilitated the global dispersal of H. sapiens.
KW  - Evolutionary ecology
KW  - Limnology
KW  - Palaeoclimate
Y1  - 2022
U6  - https://doi.org/10.1038/s41561-022-01032-y
SN  - 1752-0894
SN  - 1752-0908
VL  - 15
IS  - 10
SP  - 805
EP  - 811
PB  - Nature Publ. Group
CY  - London
ER  -