Authors:	Obrocki, Lea Marit
Title:	Advances in geoarchaeological site formation research by integrating geophysical methods, direct push sensing techniques and stratigraphic borehole data- case studies from central Europe and the western Peloponnese around ancient Olympia -
Online publication date:	24-Jun-2019
Year of first publication:	2019
Language:	english
Abstract:	The PhD thesis at hands presents a multi-methodological approach for geo-scientific research combining non-invasive geophysical and minimal-invasive direct push (DP) methods with standard sediment coring. The information value of these methods is discussed at the example of four case study sites. As main research topics differ from each case study, the methodological spectrum is adjusted correspondingly. In particular, the questions are clarified how the joint interpretation of different methods facilitate data processing and how obtained DP results may help to simplify tracing specific sediment signatures and deciphering geomorphological characteristics. Furthermore, the thesis deals with the issue how geophysical models can be improved by the integration of high-resolution DP data. In the framework of the first case study, electrical resistivity tomography (ERT) was carried out to detect and localize Mycenaean chamber tombs at three different locations in the surrounding of ancient Olympia (western Peloponnese, Greece). ERT data were first calibrated based on specific ERT signals of known and partly excavated chamber tombs at the Mycenaean necropolis of Mageiras-Kioupia. In a second step, calibrated ERT procedures were used to identify the position of unknown chamber tombs at two different other sites. ERT measurements were supplemented by ground penetrating radar (GPR) at the Epitalio site. Based on the combination of GPR and calibrated ERT data, a most probably Mycenaean cemetery consisting of a number of buried chamber tombs was localized at the Epitalio site. In contrast, ERT data helped to recognize that there are no chamber tombs at the Dartisa plateau as assumed before. The novel application of DP techniques in Geoarchaeology and Quaternary Science is shown by the example of investigations in a floodplain area in central Europe and two lagoonal environments in the western Peloponnese. The joint interpretation of ERT data, sediment core data and in situ DP electrical conductivity (DP EC) data at Großkrotzenburg (River Main, Central Europe) allowed the reconstruction of the local palaeotopography and estimation of a possible Roman harbour situation at the floodplain of the River Main at Großkrotzenburg (Hesse, Germany). Furthermore, the application of DP EC and sediment coring reveals that the overall floodplain evolution was mainly controlled by flood events. Two periods of major flooding were found, namely during late Medieval (1435-1484 cal AD) and Modern times (1646-1792 cal AD). These periods are chronologically highly consistent with the AD 1480, AD 1573 and AD 1784 flood events known by historical reports. The methodological spectrum was complemented by using the direct push hydraulic profiling tool (DP HPT) and direct push cone penetration tests (DP CPT) within two case studies at the shores of the Gulf of Kyparissia (western Peloponnese, Greece). The Gulf of Kyparissa is directly exposed to the Hellenic Arc and Trench system and therefore represents one of the seismically most active regions in Europe. Geomorphological and sedimentary signatures of past tsunami impacts were found within previous studies focusing on the Kaiafa Lagoon (KOSTER et al. 2015) and the former Mouria Lagoon (WILLERSHÄUSER et al. 2015a). Using an advanced menthodological approach, DP measurements were now carried out at both sites to test the usability of DP data for tracing high-energy sediment layers. Both, DP HPT and DP CPT data, revealed in situ high-resolution stratigraphic information of allochthonous sand sheets. Furthermore, DP data allowed the detection of erosional contacts, fining upward sequences and rip up clasts. These sedimentary signatures are related to high-energy tsunami sediment transport. Moreover, DP data showed two separate tsunami impulses. Radiocarbon age control at the Kaiafa lagoon allowed the identification of these tsunami layers as candidates for the AD 551 and AD 1303 earthquake and tsunami events. Based on regression analysis between DP and grain size data, DP data were used to trace sand sheets along transects, hundreds of meters long. Finally, DP data were combined with surface-based geophysical data. At the Kaiafa Lagoon, the integrated interpretation of DP HPT, DP CPT and ERT allowed the projection of point information to spatial dimensions. At the former Mouria Lagoon, seismic CPT (DP SCPT) data were coupled with surface-based seismic reflection data resulting in a depth conversion of seismic profile data. In this way, seismic reflection data was depth-correlated with DP parameters and grain size distribution so that the sedimentary subsurface architecture could be interpreted even beyond the maximum coring depth. The results of the present PhD study underline that the application of a multi-methodological approach in geo-scientific research strongly improves our understanding of site formation processes within space and time. Further, the use of DP techniques within the framework of sedimentological and geomorphological investigations is documented by the analysis of single DP parameters, a statistical combination of DP and sedimentary data and the integration of DP data in surface-based geophysical models. The diversity of the DP methods as well as integrated geophysical and geochemical parameters significantly increase the precision of stratigraphic data. If DP data is once calibrated by sediment core data, combined DP techniques allow for a cost- and time-efficient collection of large stratigraphic data sets.
DDC:	910 Geografie 910 Geography and travel
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 09 Chemie, Pharmazie u. Geowissensch.
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-1995
URN:	urn:nbn:de:hebis:77-diss-1000028393
Version:	Original work
Publication type:	Dissertation
License:	In Copyright
Information on rights of use:	https://rightsstatements.org/vocab/InC/1.0/
Extent:	120 Blätter
Appears in collections:	JGU-Publikationen