Fabian Welc

Preliminary report on unique laminated Holocene sediments from the Qarun Lake in Egypt

Abstract The Lake Qarun (Faiyum Oasis, northern Egypt) is a relic of the much larger Holocene lake. Past lake levels and extensions were reconstructed, based on setting of archaeological sites scattered along northern paleoshores of the ancient lake. However, geoarcheological works did not yield enough data to establish continuous environmental history of the lake. A deep drilling FA-1 on the southeastern shore of the lake, performed in 2014, supplied with a core, 26 m long that is the one of the longest lake sediment cores in northeastern Africa. The basal section of the core consisted of thin-laminated diatom marly deposits, underlain at the Late Pleistocene/Holocene boundary by coarse-grained sands. The sediment lamine were quite well developed, especially in the lower part of the core. Preliminary results indicated annually deposited sediment sequence with seasonality signals provided by microlamine of diatoms, calcite, organic matter and clastic material. Early Holocene varved sediments from the Faiyum Oasis supplied with exceptional paleoenvironmental data for northeastern Africa, which enriched a record from previous logs drilled at the southwestern margin of the Qarun Lake.

Paleoclimatological and Geoarchaeological Significance of the Holocene Loess – Soil Successions of the Tien Shan Foothills of Uzbekistan

Abstract Scenario of climate changes in the Late Pleistocene and Holocene in Central Asia is very fragmentary and inconsistent. Therefore, interaction between the development and decline of ancient cultures and the climate fluctuations are difficult to be traced. To resolve this problem, the key role can be played by multidisciplinary studies of unique Late Pleistocene and especially Holocene loess – soil succession of the Tien Shan foothills in Uzbekistan. This area yields unique successions of paleosols interbedded with loesses that are particularly useful for paleoclimate analysis. They are represented by continuous and uninterrupted sedimentary sequences with a highly varied record of magnetic susceptibility. As such, they contain a full sequence of short-term climatic oscillations of the Holocene in high resolution and therefore, in this case, they are exceptional on global scale. The correlation of Late Pleistocene and Holocene climate changes scenario with stages of development and collapse of the past human settlement in Central Asia seems at present one of the most promising research directions, in line with the substantial course of interdisciplinary research on the interaction between humans and the natural environment.

The role of geophysical ERT method to evaluate the leakproofness of diapragm wall of deep foundation trenches on the example of the construction of retail and office complex in Lublin, Poland

Abstract This paper addresses the problem of assessing the leakproofness of the bottom of a deep foundation trench, secured by cavity wall, using geophysical methods of electrical resistivity tomography. The study was conducted on a large construction project in Lublin, in a place where there are complicated soil-water conditions: the groundwater level is above the proposed depth of foundation trench, the subsoil is heterogeneous, and there are karsted and weathered carbonate sediments with confined aquifer below the bottom of the trench. A hydraulic fracture occurred at the bottom of the trench during the engineering works, which caused the water flow into the trench. In order to recognize the soil-water conditions the first stage of geophysical measurements of electrical resistivity tomography (ERT) was made. The applied methodology allowed to determine the extent of the hydraulic fracture zone within the bottom of foundation trench. In order to assess the leakproofness of Diaphragm Wall the geophysical ERT measurements were repeated (stage 2) A clear reduction in the value of the electrical resistivity of soils in the area of hydraulic fracture was caused by clay injection. The results of ERT measurements are discussed and graphically presented.

Geophysical Survey (GPR) in West Saqqara (Egypt): Preliminary Remarks

Abstract Geophysical investigations in West Saqqara area were part of the archaeological fieldwork of the Polish-Egyptian Archaeological Mission during the campaign in 2012. The main purpose of geophysical prospection using the ground-penetrating radar (GPR) was to determine the location of potential underground sepulchral structures in Saqqara necropolis. During the GPR survey, optimal depth penetration was achieved due to dry rocks and monolithic structure of ancient cemetery. Using antenna of 100 MHz, the depth of penetration was up to 45 m and with antenna of 250 MHz, up to 15 meters. Three main groups of archaeological structures were identified: Greco-Roman sarcophagi and mummies, brick-stone chapels and accompanying burial shafts; mobile objects (solid rock blocks as fragments of tombs). One of the main goal of the GPR survey was to track the route of the western part of the Dry Moat, expressed by a wide and shallow depression spreading towards north-south. It suggests that Saqqara plateau is an ideal site for using GPR surveying technology.

An Attempt to Integration of Different Geophysical Methods (Magnetic, GPR and ERT); A Case Study From the Late Roman Settlement On the Island of Rab in Croatia

Abstract In 2016 within the RED Project Roman Economy in Dalmatia: production, distribution and demand in the light of pottery workshops, 5 selected areas around the Podšilo Bay were geophysically surveyed. During the fieldworks in the Lopar protected area, located in the northeastern part of the Island of Rab a gradiometer, ground-penetrating radar (GPR) and electrical resistivity tomography (ERT) were used. The main aim of the project was to document presence of the Roman architecture in two areas of the bay’s hinterland as suggested earlier by finds of pottery and glass. Geophysical studies conducted in the Lopar area revealed presence of underground remains of ancient structures, probably from the late Roman period and connected with a ceramic production centre at the present seashore. The most interesting results were obtained for the area no. 4, the site where magnetic, georadar and ERT surveys revealed an ancient regular building at 0.4-0.6 m depth. The survey performed in the Lopar area clearly indicates that integration of different geophysical methods enables detailed and effective identification of buried archaeological structures.

Reading of Ground-Penetrating Radar (GPR) Images of Prehistoric Flint Mine; Case Study from Krzemionki Opatowskie Archaeological Site In Central Poland

Abstract Geophysical surveys conducted in order to map tunnels and vertical shafts at the Neolithic chert mining field Krzemionki used a ground-penetrating radar(GPR to test hypotheses regarding orientation, depth and subsurface complexity of these voids.Using two-dimensional reflection profiles the vertical shafts, now mostly filled with lithic debris, were easily visible. Amplitude mapping visualized debris at shaft margins as well as a collapsed material inside the voids. Some shallower horizontal tunnels were also visible as sub-horizontal planar reflections generated from both ceiling and floors of these void spaces. Extension of these interpretations to un-mapped areas of the ancient mining district and complexity of these prehistoric mining features could be examined to determine excavation intensity and exploitation techniques used during the Neolithic.

Preliminary Remarks on Enigmatic “White Casing Limestone” from Saqqara Archaeological Site in Egypt

Abstract Saqqara is one of the famous archaeological sites in the world. There is the oldest stone pyramid build by pharaoh Djoser from the Third Dynasty (around 4600 yrs BP) The components of his funerary complex were constructed of a characteristic creamish-white limestone of relatively great solidity, connected in archaeological literature with the white casing limestone from Saqqara. A source of this stone has remained so far a mystery. An extensive geological survey and other research has failed to identify any outcrops of such limestone in the vicinity of Saqqara. Preliminary results of examination of fossils from relevant rock samples of the white Saqqara limestone are presented, supplemented with discussion of current opinions concerning its origin and probable stratigraphic setting.

Results of Integrated Geoarchaeological Prospection of Unique Iron Age Hillfort Located on Radomno Lake Island in North-Eastern Poland

Abstract Archaeology of north-eastern Poland has been poorly recognized owing to vast forest areas and numerous lakes. This particularly refers to the Warmian-Masurian Voivodship, where forest covers over 30% of its area. Prospection of forested areas has become possible in Poland just over 10 years ago with the Airborne Laser Scanning (ALS) and Light Detection and Ranging (LiDAR). These techniques allow obtaining 3-D documentation of recognized and also unknown archaeological sites in the forested areas. Thanks to ALS/LiDAR prospection a significant number of archaeological structures have been identified also in the Warmia and Masuria regions. Among them oval-shaped hillforts, surrounded by perfectly spaced concentric moats and ramparts, located mainly on islands and in wetland areas, have raised particular attention. Based on field prospection and results of preliminary excavations, these objects have been considered as Iron Age hillforts. One of the best preserved objects of this type is on the Radomno Lake island, located several kilometres to the south of Iława town. Integrated geoarchaeological prospection of this hillfort emphasized benefits of using LiDAR in combination with results of geophysical prospection and shallow drillings. Applied methodology enabled to document the hillfort shape, and to study its geological structure and stratigraphy. The results clearly indicate that integration of LiDAR data with geophysical prospecting is indispensable in future archaeological surveys. It is a perfect tool for remote sensing of archaeological objects in forest areas, so far not available for traditional archaeology.

From Deserts to Glaciers: Magnetometry in Paleoenvironmental Studies in Central Asia

Central Asia is a vast area extending from the Caspian Sea to the western borders of China, with highly differentiated geography (high mountains, excessive deserts, grassy steppes), geology and anthropological history. As such it poses a perfect site for various studies, including paleoenvironmental and paleoclimatic research. Up to now, we performed two distinct studies in Central Asia: (1) a preliminary study on the Holocene loess-soil succession in the Karasu Valley, at the Tien Shan foothills in Uzbekistan; (2) and a study on development of high mountain lakes in the Pamir, based on lake sediments of the Rangkul Lake in the Eastern Pamir, Tajikistan (initial results presented here). In both studies we used magnetic properties of studied sediments and soils as one of parameters in multiproxy analyses. Paleosols from the Karasu Valley developed into continuous and uninterrupted sedimentary sequences interbedded with loess horizons. These sequences are characterized by diversified magnetic susceptibility values that reflect changes in their formation. Sediments form the Rangkul Lake show 5 significant shifts in deposition processes, caused by changes in water level. These shifts are clearly reflected both in sediment composition and in magnetic susceptibility of deposited material.

Diatom Stratigraphy of FA-1 Core, Qarun Lake, Records of Holocene Environmental and Climatic Change in Faiyum Oasis, Egypt

Abstract This study evaluates changes in the environmental and climatic conditions in the Faiyum Oasis during the Holocene based on diatom analyses of the sediment FA-1 core from the southern seashore of the Qarun Lake. The studied FA-1 core was 26 m long and covered the time span ca. 9.000 cal. yrs BP. Diatom taxa were abundant and moderately to well-preserved throughout the core sediments. Planktonic taxa were most abundant than the benthic and epiphytic forms, which were very rare and sparsely distributed. The most dominant planktonic genera were Aulacoseira and Stephanodiscus followed by frequently distribution of Cyclostephanos and Cyclotella species. The stratigraphic distribution patterns of the recorded diatoms through the Holocene sediments explained five ecological diatom groups. These groups represent distinctive environmental conditions, which were mainly related to climatic changes through the early and middle Holocene, in addition to anthropogenic activity during the late Holocene. Comparison of diatom assemblages in the studied sediment core suggests that considerable changes occurred in water level as well as salinity. There were several high stands of the freshwater lake level during humid, warmer-wet climatic phases marked by dominance of planktonic, oligohalobous and alkaliphilous diatoms alternated with lowering of the lake level and slight increases in salinity and alkalinity during warm arid conditions evident by prevalence of brackish water diatoms.