![Hier klicken, um den Treffer aus der Auswahl zu entfernen](images/unchecked.gif) |
Titel |
Influence of HCl pretreatment on laser diffraction measurements |
VerfasserIn |
Philipp Schulte, Florian Steininger, Gregori Lockot, Frank Lehmkuhl, Georg Stauch, Jens Protze, Peter Fischer |
Konferenz |
EGU General Assembly 2014
|
Medientyp |
Artikel
|
Sprache |
Englisch
|
Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 16 (2014) |
Datensatznummer |
250091742
|
Publikation (Nr.) |
EGU/EGU2014-6052.pdf |
|
|
|
Zusammenfassung |
Sample pretreatment methods in grain size (GS) analyses differ and their influence on GS
distributions has been subject of controversial discussions. The standard sample preparation
usually comprises the disaggregation into single primary particles. The organic binding
material is oxidized by hydrogen peroxide (H2O2) and the containing carbonates are
dissolved by hydrochloric acid (HCl). However, laser diffraction measurements of calcified
sediment sequences or sediments with high contents of organic matter show non-reproducible
changes in the GS distribution.
To investigate variations of the GS distribution, selected samples from two different
sections in different stages of weathering and sedimentary genesis were measured using a
Beckman Coulter LS13320 laser particle size analyser. A high-resolution Holocene
sandy loess-paleosol sequence, the Suohuduo section on the eastern margin of the
Tibetan Plateau, was investigated. The results were compared with a Pleistocene loess
sequence from the Lower Rhine Embayment, the Düsseldorf-Grafenberg section.
The entire sample set includes samples of siliciclastic, barely weathered material
and sediments from paleosols. The paleosols in the Suohudo section are strongly
influenced by steppe fires and are rich in organo-mineral associations and pyrogenic
carbon.
All samples were pretreated with hydrogen peroxide and sodium pyrophosphate. In order
to investigate the influence of HCl on the GS distribution, the samples were subsequently
prepared with and without the addition of HCl.
The results show that the sample preparation has a significant influence on the detected
GS distribution. Hence, prior to the measurement of a sample set, the effectiveness of the
pretreatment argents HCl and H2O2 should be evaluated. In order to generate a valid GS
distribution, the sample pretreatment must be matched to the aim of the study and the
composition of the sample. Paleoclimatic and environmental interpretation based on
improper GS results due to sample handling and pretreatment may be misleading. |
|
|
|
|
|