Projects
1. Deformation processes along major continental transforms
Continental transform plate boundaries are some of the most tectonically active structures on earth, producing relatively shallow and high-magnitude earthquakes within densely populated areas. We are interested to better understand the evolution and activity history of these structures from initiation to present day activity pattern. Previous projects in the Dead Sea Transform and the Eastern California Shear Zone demonstrated the reactivation behavior and the non-uniform activity pattern of these long-lived structures. Current projects are focused on the North Anatolian Fault Zone.
2. Strain accumulation and reoccurrences of paleoseismic events
The general concept of “earthquake cycle” is based on limited paleoseismological archives from the past 20,000. These records are essential for our understanding of faults behavior and the seismic cycle. In recent years, studies of crack-seal veins provided important information on their growth mechanisms, demonstrating their periodicity and potential to preserve the seismic cycle (both seismic and a-seismic periods). Our group advocate for the use of crack-seal type veins as potential archives for studying deformation rates, reoccurrences of events, and for temporally constraining the seismic cycle and we currently apply this method along the active North Anatolian Fault Zone.
3. Strain accumulation and reoccurrences of paleoseismic events
The general concept of “earthquake cycle” is based on limited paleoseismological archives from the past 20,000. These records are essential for our understanding of faults behavior and the seismic cycle. In recent years, studies of crack-seal veins provided important information on their growth mechanisms, demonstrating their periodicity and potential to preserve the seismic cycle (both seismic and a-seismic periods). Our group advocate for the use of crack-seal type veins as potential archives for studying deformation rates, reoccurrences of events, and for temporally constraining the seismic cycle and we currently apply this method along the active North Anatolian Fault Zone.
4. Dating of primary and secondary carbonates
Our group has experience with dating of various types of carbonate material including secondary carbonates such as nodules, microcodiumsm, cements, oncoids, speleothems, and stromatolites. We have also successfully dated primary dolomite and limestone units from the Archean time to the Pliocene. Following a textural study of the sample we mechanically separate several sub-samples from small microstructures using microdrilling device. Following a column-chemistry separation in clean-lab environment, the U-Pb or U-Th isotopes of several sub-samples are used to construct a Terra-Wasserburg or U-Th isochron ages, respectively. We are interested in working with new material and potentially other minerals with low-uranium content (
5. Calibration of absolute time in Earth’s history using sedimentary archives
The quantification of the Geological time scale relies on detailed and accurate geochronology. We contribute to a series of research projects using high precision U-Pb geochronology of zircon in volcanic ash beds interlayered with sedimentary strata. This technique was applied to Ediacaran-Cambrian boundary (Linnemann et al., 2018) ; calibration of late Carboniferous (Pointon et al., 2012); lower and middle Triassic (Ovtcharova et al., 2006; Galfetti et al., 2007) and Paleocene-Eocene thermal maximum (in progress). This research was combined with developing strategies for the accurate definition of geological boundaries in complex sedimentary sections and developing a probabilistic approach for accurate interpretation of complex geochronological U-Pb results (Ovtcharova et al., 2015).
6. Resolving magmatic processes: differentiation, duration, crystallization and cooling history
The recent research in the field of magmatic petrology brings evidence that plutons are incrementally assembled by repeated magma injections and eventually build up huge complexes over extended periods of time. Timescales of pluton construction may vary from 104 to 106 years (in most Phanerozoic igneous complexes) to 108 years (in massif Anorthosites of the Proterozoic). Using high precision, chemical abrasion, isotope dilution thermal ionization mass spectrometry (CA-ID-TIMS) U-Pb zircon geochronology and high precision U-Pb on baddeleyites it is possible to resolve individual magma pulses and to track both the thermal and crystallization histories of magmatic systems at high temporal resolution. Examples of this approach are the results of our work in the Rustenburg Layered Suite (RLS) of the Bushveld Complex, which represents Earth’s oldest large igneous province crystalised in < 1 Ma (Zeh et al., 2015) and our current research on Kunene Anorthosite Complex in Angola and Namibia.
7. Resolving processes in ore deposits (duration and mechanism of ore formation)
The timing of magmatism also has tremendous implications for the style and timescales of magmatic-hydrothermal ore deposits (Chiaradia et al., 2013). In order to provide the temporal link between magmatism and ore formation we apply high precision U-Pb dating of various magmatic (zircon, titanite, rutile) and some hydrothermal minerals (apatite, titanite, monazite, xenotime, rutile) and combine this with element chemical analyses both in-situ before, and in solution after dissolution of the dated minerals, as well as Hf isotope analysis. A major analytical problem to overcome is the partial loss of radiogenic Pb in zircon, which is related to the hydrothermal fluids that are in contact with the grain. In addition, precision of U-Pb dates in igneous zircon associated with ore deposits gets compromised by the presence of melt inclusions and elevated common Pb in the zircon lattice, which results in low radiogenic to common lead ratios. Nevertheless, the results obtained in our lab for several projects of the Ore deposit group in Geneva (mainly for ore deposits in Peru), in combination with a wealth of other geochronological, chemical and petrological analyses brought interesting outcomes (Chelle-Michou et al., 2014; Catchpole et al., 2015; Kouzmanov et al., 2008).
8. Quantify absolute time in the evolution of early terrestrial life
The 4.5-billion-year long Earth history has passed several milestones. One of them, at approximately 540 Ma, was the so called “Cambrian explosion” – an eruption of complex life recorded in fossils from around the world. This huge evolutionary jump from simple to more complex life forms happened after one unique first experiment – the late Neoproterozoic Ediacaran biota, which similarly to the Cambrian explosion started with rapid diversification but then declined and faded away, giving place to the more successful Cambrian metazoans. Whether Ediacaran-type biota gradually evolved into Cambrian biota, disappeared after a long decline or became rapidly extinct due to external, environmentally driven forces in the Early Cambrian remains the subject of debate. We aim to establish a more robust timescale for the evolution of Ediacaran biota as a function of time and paleo-latitude and to link their evolution to environmental changes. The research is carried out in several Ediacaran sections in Namibia, Ukraine, Ural and linked to a international GRIND drilling project via collaboration with Ulf Linnemann from Senckenberg Museum, Dresden (Linnemann et al., 2018; Soldatenko et al., 2019).
9. Petrogenesis of magmatic rocks from different geodynamic settings
Whole rock, bulk sediment and dust analysis. Applications: petrogenetic magmatic processes in various geodynamic settings, tectonic and paleo-environmental changes from sedimentary sequences and marine sediments, anthropogenic processes.
10. Metallogenetic processes
Mineral analysis (silicates, sulphides, sulphates, phosphates, oxides, carbonates). Applications: trace magmatic and hydrothermal ore-forming processes.
11. Trace sources of fluids in ore deposits
Fluid analysis (fluid inclusions in minerals through the crush-leach technique, volcanic gases, organic fluids, waters). Applications: trace sources of fluids in ore deposits, behavior of metals during volcanic degassing.
12. Paleoenvironmental changes
Fossil analysis (carbonate and apatite down to sub-mg amounts). Applications: indirect dating of marine rocks (Sr isotope chronostratigraphic method) and tracing pre-historic human migrations.
13. Anthropogenic processes
Modern and ancient handcraft analysis. Applications: forensic and archeometric studies.
14. Thermal history
Thermal history solution for a Triassic granite in the Eastern Cordillera of Ecuador. The data support a model of Mesozoic extension, and exhumation due to the collision of an oceanic plateau at 75 Ma.
15. Fluid circulation
40Ar/39Ar analysis of multiple generations of alunite constrain the date and timing of individual fluid circulation events associated with high-sulphidation Au mineralisation, Western Cordillera, Peru.
16. Palaeodepths
Palaeodepths of the current surface of the highly metallogenic Mt. Isa Inlier, Australia, constrained using low temperature thermochronology.
17. Timing
In-situ 40Ar/39Ar analyses in gem-quality K-feldspar constrain the time of dissolution-reprecipitation events, Madagascar.
