Christian Laag

Christian Laag
Institut de Physique du Globe de Paris · Paleomagnetism Research Group

PhD candidate M.Sc.

About

40
Publications
7,848
Reads
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73
Citations
Citations since 2016
40 Research Items
73 Citations
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Introduction
My current research interest centers on chronology and stratigraphy of terrestrial sedimentary archives, of the Middle and Lower Danube-Basins, India, and Cameroon. I apply and combine in-depth enviro- and palaeomagnetic approaches, colorimetry (VIS), ATR-FTIR (MIR), granulometry, tephrostratigrapy, cyclostratigraphy, etc..., to detect Quaternary environmental changes for the last 1 millon years. Hence I apply in-depth GIS analysis for volcanic regions e.g., the Cameroon Volcanic Line.

Publications

Publications (40)
Method
Enhance and visualise stratigraphic colour profiles and decipher hidden features in loess-palaeosol records.
Conference Paper
Full-text available
Eastern European loess-paleosol sequences (LPS) are excellent archives of past climate change. Millennial-timescale climate change is successfully evidenced in loess of the last and penultimate glacial periods. However, study designs with similar or lower sampling resolution strategies and/or single proxy investigations do not favor their identific...
Article
Loess Paleosol Sequences (LPS) are valuable archives of climatic and environmental change in terrestrial systems and contribute to local and global dust systems. Due to their widespread occurrence across continents, LPS are well suited to study the interface of climate subsystems, on different time scales. Yet, high-resolution investigations of LPS...
Article
Loess-paleosol sequences (LPS) from the Lower Danube area are valuable terrestrial archives of environmental change in SE Europe during the Pleistocene. A twenty-seven meters thick sequence has been sampled in Central North Bulgaria near the city of Pleven within the Suhia Kladenetz (SK) quarry. The sedimentary sequence consists of seven loess unit...
Article
Full-text available
Volcanic eruptions represent hazards for local communities and infrastructure. Monogenetic volcanoes (usually) erupt only once, and then volcanic activity moves to another location, making quantitative assessment of eruptive hazards challenging. Spatio-temporal patterns in the occurrence of these eruptions may provide valuable information on locati...
Conference Paper
Full-text available
Loess-paleosol sequences of the Lower Danube region are valuable terrestrial archives of past climate change, up to about 1 Myrs in certain locations. Previous studies on these archives have provided insightful views of past environmental changes but sometimes limited by low-resolution sampling, hiatus or short time coverage, or mono-disciplinary a...
Poster
Full-text available
Loess-paleosol sequences (LPS) of the Lower Danube region provide high resolution records of Pleistocene climate change. Tephra layers (volcanic ashes) are valuable chronological marker horizons in sedimentary sequences and overcome issues of correlative age models and e.g., limitations of absolute dating methods. Tephra occurrences observed within...
Conference Paper
Full-text available
Loess-paleosol sequences (LPSs) are aeolian terrestrial paleoclimate archives able to conserve several hundreds of thousands years of climate history. Loess deposits cover at least 10 % of the northern hemisphere continental masses (Pécsi, 1990) and provide adequate properties to conserve climate changes imprinted in the stratigraphically analyzabl...
Conference Paper
Full-text available
Terrestrial climate archives like loess-paleosol sequences (LPSs) located in Eastern Europe are known to cover long periods of time and record climate fluctuations over the last hundreds of thousands of years (e.g. 1). Glacial cold and dry conditions, leading to loess accumulation, alternate with interglacial, warm and humid episodes, leading to th...
Article
Full-text available
Abstract Luminescence phenomena of insulators and semiconductors (e.g., natural minerals such as quartz) have various application domains. For instance, Earth Sciences and archaeology exploit luminescence as a dating method. Herein, we present the R package RLumCarlo implementing sets of luminescence models to be simulated with Monte Carlo (MC) met...
Article
A high-resolution analysis of the Zmajevac loess-palaeosol sequence in East Croatia (Baranja) was performed with the purpose to get new insights into the palaeoenvironmental history during the last three glacial-interglacial cycles. The post-IR infrared stimulated luminescence signal of feldspar, stimulated at 290°C (thereafter pIRIR290) was used t...
Article
Full-text available
In mid-latitude Eurasia, loess-paleosol sequences (LPS) provide the most widespread sedimentary records of Quaternary paleoenvironmental evolution. In the Middle Danube Basin (MDB), these archives cover at least the last million years of climate history, and occasionally contain archeological findings. The studied Zemun LPS is located on the right...
Conference Paper
Full-text available
Loess-paleosol sequences (LPSs) are proven valuable archives for continental paleoclimatic reconstructions. However, studied LPSs worldwide, spanning multiple glacial-interglacial cycles, are seldomly sampled and analyzed at a continuous high resolution. Exceptionally, in a quarry setting near the city of Pleven (Bulgaria), a new LPS, with a thickn...
Conference Paper
Full-text available
Volcanic eruptions may constitute a severe threat for local communities and their infrastructure. Important information as to the prediction of future eruption sites and the likelihood of activity can be obtained by analysis of spatio-temporal eruption pattern in an area of interest. The fact that monogenetic volcanoes, unlike polygenetic ones, eru...
Article
Full-text available
Loess-paleosol sequences (LPSs) are important terrestrial archives of paleoenvironmental and paleoclimatic information. One of the main obstacles for the investigation and interpretation of these archives is the uncertainty of their age-depth relationship. In this study, four different dating techniques were applied to the Late Pleistocene to Holoc...
Article
The southern Caspian Lowland sensitively reacted to Pleistocene climate change and is a key area for reconstructing climate dynamics and landscape evolution in Southern Eurasia. Loess-paleosol sequences (LPS) of the northern foothills of Alborz Mountains provide detailed records of climate-induced changes of dust accumulation and soil formation cor...
Conference Paper
Full-text available
Loess palaeosol sequences (LPSs) are terrestrial climatic archives capable of recording past climatic change. In particular, the alternation of interglacial and glacial periods is recognized in LPSs as intercalated buried soils (palaeosols) within loess units. For LPSs of the Eurasian loess belt, correlating low-frequency magnetic susceptibility (χ...
Presentation
Full-text available
Integrating magnetic susceptibility and colorimetric parameters for paleoenvironmental reconstructions from loess-paleosol sequences. A case study from the Middle Danube Basin. The full video of my talk can be found on Youtube under the following link: https://www.youtube.com/watch?v=7PjUdBfAHZE
Data
The site Balta Alba Kurgan (BAK) in Romania was studied in the frame of a multi-method dating approach, including optical stimulated luminescence, radiocarbon dating, magnetic stratigraphy and tephrochronology. Here, we present the results of the magnetic stratigraphy approach. Oriented samples obtained from the sub-sections BAK2 and BAK4 were comb...
Conference Paper
Full-text available
Loess-palaeosol sequences (LPSs) are valuable records of Quaternary environmental change, especially in the northern hemisphere. In Eurasian LPS, the alternation of loess and palaeosol intervals reflects the uninterrupted but fluctuating dust deposition during the Quaternary and the fluctuations of temperature and precipitation responsible for the...
Article
Full-text available
We present the findings from analysis and modeling of a stratigraphic series of magnetic susceptibility (MS) data measured with a portable MS meter from the Permian Salagou Formation loessite (south-central France). The results reveal discernible Milankovitch-scale paleoclimatic variability throughout the Salagou Formation, recording astronomically...
Poster
Full-text available
Loess-palaeosol sequences (LPSs) provide the most important northern hemispheric terrestrial Quaternary palaeoenvironmental records. In the Middle Danube basin, these archives cover the last million years (Marković et al., 2015) of climate history and contain archaeological horizons from occupations by early humans. The Zemun loess site (ZLS, locat...
Conference Paper
Full-text available
Loess palaeosol sequences (LPSs), widely spread over the northern hemisphere and especially Eurasia, are valuable records for various palaeoenvironmental parameters. Here, a LPS from northern Iran (Agh Band) was analysed in terms of rock-and palaeomagnetic proxies. The study site is located in the so-called Iranian loess plateau with an average ann...
Article
Phenomenological models are frequently used to analyze experimental signals in thermally and optically stimulated luminescence experiments. Typically, these models consist of systems of differential equations describing various electronic transitions. An alternative to the differential equation approach is the use of Monte Carlo (MC) methods, which...
Poster
Full-text available
Central European loess-palaeosol sequences (LPS) are valuable recorders of Late Pleistocene climatic change Bialy Kościół (BK) section is located in Lower Silesia c. 130 km. of the last glacial maximum ice extent. BK LPS is considered to be one of the most complete LPS in SW-Poland covering the last glacial cycle (LGC). Recording since latest Pleis...
Conference Paper
Full-text available
Central European loess-palaeosol sequences (LPS) are valuable recorders of Late Pleistocene climatic change, especially in areas where other geoarchives are rare or absent. However, in the vicinity of the ice margins mid latitude last glacial loess sequences are strongly influenced by periglacially controlled humidity variations. Deep seasonal fros...
Conference Paper
Full-text available
For risk assessment and for deciphering the spatio-temporal activity pattern in a specific volcanic field, it is important to establish an eruption chronology. However, Holocene and Late Pleistocene volcanoes often challenge conventional radiometric dating techniques (e.g., 40Ar/39Ar, 14C or luminescence methods) due to absence of datable material...
Conference Paper
Full-text available
The magnitude of volcanic eruptions and the volume of ejected magma control amongst other factors the thickness and geographical extent of tephra layers. Here we present and discuss new data on the extent of the "L2-Tephra" preserved in loess-palaeosol sequences (LPSs) on the Balkan Peninsula. Magnetic susceptibility and colorimetric data from the...

Questions

Questions (5)
Question
Dear all,
i have the following problem. I am measuring on a VSM hysteresis and FORCs on loess sediments and volcanic glass shards. The material is filled prior measurement into the gelatine capsules and compressed by a metal stick fitting exactly inside the capsule. The filling process is divided in several steps, e.g. filling a thin layer of material, then compression, then the next layer (and so on). The lid of the gelatine capsule is filled the same way to a distinct point, then bottom and lid are closed with a final compression made by pressing both parts per hand together. Results of this technique are very good and even megnetically weak samples show during IRM acquisition or hysteresis loop measurements nearly no noise. In opposite, measuring volcanic glass shard containing material (coarser material), the compression is very hard to reach and the resulting FORCs are very noisy and so are IRM acquisitions and hysteresis loops (mostly you see it in the FORCs). I even measure several FORCs to stack afterwards but by analyzing the data, the FORCs are still noisy. What i observed is, that when "long time" experiments (ca. 2-2.5 hours per FORC and 6-7 FORCs per sample in a row) finer material starts to accumulate at the base and the top of the gelatine capsule due to the vibration of the VSM over a long time. My idea was to saturate the material with glue and i tried different ones with different viscosities. Due to the large surface of the grains inside the capsule, many glues which are low in viscosity get hard immediately and inable to saturate the content of the capsule, but high viscosity glues or gels are not able to saturate the material inside the capsule (since the space between the different grains is too small).
Did anyone had the same problems or could recommend me a (in best case non-magnetic) glue with very low viscosity and at the same time very low in hardening (I do not care if I have to wait for the next day (s) until the hardening is completed)?
Thank you very much in advance,
Chris
Question
Dear all,
I am desperately searching for a study investigating colorimetric /DRS fluctuations of the last 500 kyrs from one of the major Chinese loess profiles. So far, I only found DRS data from the last Interglacial/Glacial cycle, but cannot find any dataset containing continuous colorimetric / DRS data from a LPS (e.g. Luochuan) covering at least the last 4 Interglacial/Glacial cycles. I would be more than thankful and happy for any hint or suggestion.
Thank you all very much,
Chris
Question
Dear all,
I am working with a spectrophotometer and receive (besides DRS data in 10 nm steps ranging from 400 to 700 nm) parameters for Luminance (L*), blueness (b*) and redness (a*). I wonder how these parameters are calculated from the DRS data. I use a Konica Minolta CM700d device. Thanks a lot in advance for your help and have a great evening,
Chris
Question
Dear colleagues,
since I demagnetized orientated loess samples by applied fields of a demagnetizer with a increaing field intensity and more than 10-15 steps per sample, i saw in these samples intensities anomalies. These anomalies don't follow the regular (quasi negative exponential fit) vs. the applied field and sometimes increase. Gyro-remanences can be excluded because after a short increase of the samples' intensity, there is a continuouse decrease following. Error parameters don't show a significant anomaly.
I would be very happy about any idea. Kind regards, Chris
Question
UZ: Orkutsay, Karasu
PL: Adamowka, Augustow, Bojanice, Buskowice, Busno
UA: Baburka, Boyanichi, Budeshty Cosautsi, Dnepropetrovsk Doroshivtsi
RUS: Berkeevo, Borisoglebsk,, Budennovsk, Domnovo
SLO: Bled
HUN: Bodrogkeresztur
SRB: Brus
SLK: Brusno
ROM: Cladova, Dobresti,
Thanks a lot for your help!
Best regards, Chris

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Projects

Project (1)
Project
Making a table format, called pmob (for PaleoMagnetic OBject), implemented in R, to serve as an intermediary for the conversion of all paleomagnetic data format into each other