Loess; paleosols; lipid biomarkers; isotopes; paleoclimatology; glacial cycles; Loess; paleosols; biomarkers; isotopes; paleoclimatology; Quaternary; glacial cycles; alkanes; fatty acids; GDGTs
Zech Michael, Tuthorn Mario, Detsch Florian, Rozanski Kazimierz, Zech Roland, Zoeller Ludwig, Zech Wolfgang, Glaser Bruno (2013), A 220 ka terrestrial delta O-18 and deuterium excess biomarker record from an eolian permafrost paleosol sequence, NE-Siberia, in CHEMICAL GEOLOGY
, 360, 220-230.
Zech Roland, Zech Michael, Markovic Slobodan, Hambach Ulrich, Huang Yongsong (2013), Humid glacials, arid interglacials? Critical thoughts on pedogenesis and paleoclimate based on multi-proxy analyses of the loess-paleosol sequence Crvenka, Northern Serbia, in PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
, 387, 165-175.
Suter I., Zech R., Anet J., Peter T. (2013), Impact of geomagnetic events on atmospheric chemistry and dynamics, in Climate of the Past Discussion
, 9, 6605-6633.
Häggi C., Zech R., McIntyre C., Eglinton T. (2013), On the stratigraphic integrity of leaf-wax biomarkers in loess-paleosols, in Biogeosciences Discussion
, 10, 16903-1692.
Zech Roland (2012), A permafrost glacial hypothesis – Permafrost carbon might help explaining the Pleistocene ice ages, in Quaternary Science Journal - Eiszeitalter & Gegenwart
, 61, 84-92.
Zech R, Gao L, Tarozo R, Huang Y (2012), Branched glycerol dialkyl glycerol tetraethers in Pleistocene loess-paleosol sequences: Three case studies, in ORGANIC GEOCHEMISTRY
, 53, 38-44.
Zech Roland, Huang Yongsong, Zech Michael, Tarozo Rafael, Zech Wolfgang (2011), High carbon sequestration in Siberian permafrost loess-paleosols during glacials, in Climate of the Past
, 7, 501-509.
Zech Michael, Zech Roland, Buggle Björn, Zöller Ludwig (2011), Novel methodological approaches in loess research – interrogating biomarkers and compound-specifc stable isotopes, in Eiszeitalter & Gegenwart - Quaternary Science Journal
, 60, 170-187.
Loess-paleosol sequences (LPS) are unique terrestrial archives for Quaternary (~2 Ma) climate and environmental reconstruction. By analogy to the findings from the famous Chinese Loess Plateau, LPS in Europe, Central Asia and Siberia have often been interpreted to document the succession of warm, humid interglacials and cold, arid glacials. However, the value of LPS has not yet been fully exploited, in part because quantitative paleoclimatic information, particularly regarding temperature and precipitation, has been difficult to obtain. Recent innovations in organic biogeochemistry made possible by methodological developments are poised to catalyze a new era of terrestrial paleoclimate research.The aim of the proposed research project was to reconstruct climate and environmental changes from key LPS in southeast Europe, Central Asia, southern and northern Siberia applying various novel molecular proxies:(i) Lipid biomarkers derived from soil bacteria (GDGTs),(ii) leaf wax biomarkers (long-chain n-alkanes and fatty acids), and(iii) compound-specific deuterium analyses on the leaf waxes. Results: Leaf wax biomarkers in the LPS Darai Kalon (Tajikistan), Igetei, Kurtak, and Iskitim (Siberia) indicate a variable, but constant presence of deciduous trees during the last glacial. The general notion of pronounced glacial aridity and predominance of grasses over trees is not fully supported. Mean annual temperatures (MAT) inferred from GDGT lipids don’t reflect the expected glacial-interglacial changes, and GDGTs should be interpreted with caution. Compound-specific deuterium analyses reveal more depleted values during glacials and more enriched values during interglacials, documenting the dominant temperature control and the great potential of these analyses for climate reconstructions in Siberia. Topsoil samples corroborate the usefulness of leaf wax biomarkers for the reconstruction of past vegetation, and compound-specific radiocarbon dating showed the stratigraphic integrity of these compounds, i.e. no significant post-sedimentary overprint related to roots or microorganisms. The combination of compound-specific deuterium and oxygen isotope analyses has great potential for quantitative paleoclimatic reconstructions in LPS and lacustrine sediments.