Dear All,
next week, we’ll have a joint session with the LTCC (Long Term Climate Change) seminar. Kay Beets and Maarten Prins (VU University Amsterdam) will giva a talk about
Past seasonality changes in the East Asian Monsoon inferred from dust, biomarkers and isotopes as recorded in Chinese loess-paleosol sequences
(LTCC seminar invitation and abstract below)
Time & Loc.:
16.00, 15.10.2013, C108 Physicum, Kumpula
Welcome,
Allu
Welcome!
***
Dear all,
The first Long Term Climate Change (LTCC) seminar of this autumn will take
place next TUESDAY 15.10. at 16.00 o’clock (together with Kurten club) in
lecture room C108 at the Department of Geosciences and Geography, Physicum.
The first seminar will be given by assistant professors Kay Beets and
Maarten Prins (VU University Amsterdam): Past seasonality changes in the
East Asian Monsoon inferred from dust, biomarkers and isotopes as recorded
in Chinese loess-paleosol sequences (see the abstract below)
The following LTCC seminars will take place roughly every second THURSDAY at
14.15. The upcoming seminars are:
7.11.2013 Tiina Ronkainen (Environmental Change Research Unit (ECRU)
Department of Environmental Sciences): Biomarkers – a new potential method
to study highly humified peat components
21.11.2013 Minna Väliranta:
5.12.2013 Outi Hyttinen ja Aarno Kotilainen: IODP Expedition 347 in
the Baltic Sea
Students will get credit points for attending the ECO and LTCC seminar
series and keeping a seminar journal / summary. The seminar journal consists
of a series of (at least) one-page summaries of each seminar you attend,
detailing the motivating questions, methods, key results and main
conclusions of the presented research. Writing and submitting 5 well-written
summaries is good for 1 cp and 10 summaries will earn 2 cp (maximum of 2 cp
total). The journals can be written in English or in Finnish, and credits
can be collected by any combination of ECO/LTCC seminars.
All welcome!
Anu Kaakinen
***
PAST SEASONALITY CHANGES IN THE EAST ASIAN MONSOON INFERRED FROM DUST,
BIOMARKERS AND ISOTOPES AS RECORDED IN CHINESE LOESS-PALEOSOL SEQUENCES
Kay Beets & Maarten Prins
VU University Amsterdam, Faculty of Earth and Life Sciences, Department of
Earth Sciences, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
(e-mail: c.j.beets@vu.nl, m.a.prins@vu.nl)
The grain-size distributions of Chinese loess–paleosol sequences provide
information on sediment provenance, transport pathways and East Asian
monsoon variability. Previous studies have indicated that a genetically
meaningful decomposition of grain-size distributions can be accomplished
with the end-member modelling algorithm EMMA. The unmixing results reveal
that two dust supply patterns were active over northern China during the
Late Quaternary: (i) background sedimentation of fine-grained dust, (ii)
episodic, highly variable input of coarse-grained dust. The coarse dust
fraction is supplied by modified saltation and short-term suspension
processes during major dust outbreaks in spring. Characterisation of the
coarse dust component allows for a reconstruction of winter monsoon
variability.
Especially the Mangshan loess-paleosol sequence, deposited on the south bank
of the Yellow River near Zhengzhou, provides an interesting opportunity to
unravel variations in monsoon seasonality, because of its high accumulation
rate and the predominance of the river floodplain as a nearby sediment
source.
Here we present our first results obtained with the innovative dynamic image
analysis sensor QICPIC (Sympatec). The QICPIC combines particle size and
shape analysis of non-spherical suspended sediment particles with high
precision and accuracy. The high performance camera supports the grabbing of
up to 500 images per second, resulting in the storage of size and shape data
of a few million individual particles in a few minutes time. The QICPIC
seems especially promising for the high-precision identification of
paleo-dust storm events in loess-paleosol sequences.
With the use of stable isotopic composition of the growth increments of
fossil land snail shells and of bulk rhizoliths, we can distinguish the
seasonal contrast changes over millennial-scale climate variations during
the last glacial-interglacial cycle. New biomarker data, the MBT-CBT
paleothermometer, provide additional constraints on past climate. The
combination of aforementioned techniques allows a more robust reconstruction
of how local conditions responded to large-scale climate reorganisation over
the last ~130 kyr.