Florian Ströbele | Leibniz-Zentrum für Archäologie (original) (raw)

Papers by Florian Ströbele

The „Adelhauser Tragaltar“ – an opportunity for studying materials and technologies of the Caroli... more The „Adelhauser Tragaltar“ – an opportunity for studying materials and technologies of the Carolingian period

The portable altar from Adelhausen monastery in Freiburg (Breisgau, south-western Germany) is known as one of the major works of Carolingian goldsmith’s art in Europe. It bears witness to arts and crafts of a period characterized by a pronounced scarcity of both written sources on technologies applied and well-dated archaeological material on the other side. The altar is nowadays housed in the collections of the Augustinermuseum in Freiburg. In commemoration of Charlemagne’s death 1250 years ago, the custodians of the Museum planned a small exhibition to be created around this altar. During the preparation of this exhibition it became evident that it would be an excellent occasion to examine the Adelhausen portable altar in terms of its technological and material make-up in order to complement the art-historical research conducted. Scientific studies on the material had never been done before and researchers from different disciplines joined in the effort to solve some of the altar’s enigmas. For the scientific studies of the materials the altar was allowed to leave Freiburg for a period of three days in 2013. All analyses had to be performed without any sampling or mechanical intervention of any kind. The analyses were performed in the XRF XXL-sample chamber of the RGZM archaeometry lab.

The altar consists of a rectangular wooden panel made of oak inlaid in its central part with a slab made from reddish porphyry. The panel is lined on both long sides with blue and red opaque enamelling set in round metal frames reminiscent of continental-style so called “Kreuzemailfibeln”. Framing the central porphyry plate there are silver metal sheets bearing translucent enamel cells in different colours (blue, green, rose and opaque white) as well as a decorative pattern with deepened gilded lines and Niello.

The analytical aim was to characterize the materials in order to identify separate original material from later additions and add information as to the time frame and regional context of the manufacturing of the altar. One important goals was to verify assumptions as to stylistic proximity to contemporaneous enamels from Italy and Belgium on the basis of enamelling technology.

The analysis showed that the gilding was entirely a fire-gilding with mercury in amounts of several percent as typical for this technique. The niello belongs to the silver-copper sulphide type and is still sintered to the plates in contrary to the melting- variety with addition of lead that appears in the 9th century for the first time. The silver is of high quality. With the results on the composition of the different copper alloys building up the cells for the enamelling, it was possible to identify the construction principle of the setting. Several rivets were analyzed that were clearly made from modern material.

X-ray radiography indicated the presence of two small hollow chambers with a faint trace of some organic material. Later CT studies in Freiburg revealed the existence of two hitherto postulated reliquary “chambers”.

An important point was the identification of the glass type as well as colouring and opacifying agents in the enamels. The base of all enamels was soda-silica glass produced with mineral natron as a fluxing agent. No wood-ash or plant-ash glass was detected. One of several varieties of opaque red enamels was made with lead glass. Calciumantimonate was used as an opacifier for blue, turquoise and white enamels while copper-oxide was used for red. Blue is due to a combination of copper and cobalt, while the turquoise enamel is coloured with copper only. Ionic copper is the source of the colour in the translucent green enamels as well. Manganese was added to one of the translucent enamels, probably to decolourize it, but in the end leaving this enamel type with a rather rose tinge.
The information gained from the analytical study formed the basis for comparison with published analyses from Carolingian art works from Italy (San Ambrogio altar) or Dorestad in Belgium (enamelled fibula fragments). It could be stated that there was no match for the glass type(s) used in combination with the colouring or opacifying agents. Several Carolingian “Kreuzemail” fibula from collections in Germany were analyzed as well in order to look for technological affinities. Here, again, the similarities were not convincing.

To summarize: the analyses add considerably to the yet scarce knowledge on Carolingian technology and material traditions. Some assumptions of technological affinities to some of the works in Italy and Belgium were not supported by the analytical findings. In view of the limited information we have, the significance of variation in material and technology can not be assessed sufficiently in terms of workshop ascriptions.

HONFOGLALÁS KORI FÉMLELETEK ANYAGÖSSZETÉTELI VIZSGÁLATA KÉSZÍTÉSTECHNIKÁJUK ÉS NYERSANYAGFORRÁSUK... more HONFOGLALÁS KORI FÉMLELETEK ANYAGÖSSZETÉTELI
VIZSGÁLATA KÉSZÍTÉSTECHNIKÁJUK ÉS
NYERSANYAGFORRÁSUK TÜKRÉBEN

In: Körlin, G., Prange, M., Stöllner, T., Ünsal, Y. (Hrsg.). From Bright Ores to Shiny Metals – Festschrift Andres Hauptmann. Der Anschnitt, Beiheft 29, 229-232. Deutsches Bergbaumuseum Bochum. Bochum 2016

Knaller, R., Ströbele, F. (2014) The heritage of Tang dynasty textiles from the Famen Temple, Shaanxi, China: Technological and stable isotope studies. Studies in Conservation. 59, Supplement 1, 62-65, International Institute for Conservation of Historic and Artistic Works Congress 2014, Hong Kong

Ströbele, F., Eckmann Ch., Broschat, K. (2015) Analysen an Goldblechen und Goldblechfragmenten aus dem Grab des Tutanchamun (Ägypten, 18. Dynastie). Metalla, Sonderheft , 183 - 185, Archäometrie und Denkmalpflege 2015, Mainz

Poporadze, N., Kalandadze, O., Seskuria, F., Ströbele, F. (2014) Complex study of the disk and rod found in the Kurgan Ananuri 3. Journal of the Georgian Archaeology, Vol. 22, 216-222

This paper is primarily concerned with the new evidence from the technical study of the items of ... more This paper is primarily concerned with the new evidence from the technical study of the items of the III millennium
B.C. from the Ananauri № 3 Kurgan (excavated in 2012, head of the archaeological excavation. Z. Makharadze). The
diameter of the burial mound is 100 m and it is 12 m high. Two four-wheeled wooden hearses were discovered in the
burial .The hearse № 1 was found in the south- western part and the hearse № 2 – in the north-western part.
In Article the attention paid to the technical study of the pin with disk, which was used in construction of the
wooden wheels. The items from Kurgan were examined using microscopy, X-radiography, X-ray fluorescence analysis
and X-ray diffraction. The technical study of the above mentioned items shows that, pin with disco consist mixture of
minerals. Part of the authors think that the material used for manufacturing pin with disc from the outset was mineral,
and part of authors think, that this is a case of corrosion and that the pin with disco was originally made from copper .

In: Greiff, S., Schiavone, R., Zhang, J., Hou, G., Yang, J. (Hrsg.). The Tomb of Li Chui – Interdisciplinary Studies into a Tang Period Finds Assemblage. 355-369. Monographien des Römisch-Germanischen Zentralmuseums 117 . Römisch-Germanisches Zentralmuseum, Mainz

Ströbele, F., Hildebrandt, L.H., Baumann, A., Pernicka, E., Markl, G. (2014): Pb isotope data of Roman and Medieval objects from Wiesloch near Heidelberg, Germany. Archaeological and Anthropological Sciences, Vol. 7, 4, 465-472. DOI 10.1007/s12520-014-0208-1

Lead isotope abundance ratios have become a reliable and common tool for obtaining information o... more Lead isotope abundance ratios have become a reliable
and common tool for obtaining information on the provenance
of archaeological material containing lead. This paper
presents Pb-isotope data of lead-silver smelting relics dating to
the High Middle Ages, data from Roman objects, as well as
data from objects of various other periods fromWiesloch and
the surrounding area. The results are compared to Pb-isotope
data from theWiesloch Pb-Zn deposit and some Rhenish lead
deposits. Results indicate that during the Roman period, only
local lead was used at Wiesloch, while during later periods,
lead from other sources is also present.

Monographien des Römisch-Germanischen Zentralmuseums, Dec 5, 2013

Neues Jahrbuch für Mineralogie, Abhandlungen, Sep 1, 2012

Southwest Germany hosts a variety of Permian to Cenozoic hydrothermal mineralizations of differen... more Southwest Germany hosts a variety of Permian to Cenozoic hydrothermal mineralizations of different types. Veins are most abundant, but also Mississippi-Valley type and other stratabound mineralizations are present. This contribution presents a set of Pb isotope data for ore minerals from these mineralizations as well as isotope data of possible source rocks for the Pb. We show that lead isotope ratios of the mineralizations depend on the source rocks, the age of a given mineralization and its tectonic setting. For example, Pb isotope ratios of Jurassic mineralizations show a trend to higher isotope ratios towards the south. The reason for this might be the higher exhumation rate in the southern Schwarzwald that exposes deeper crustal levels. There, the infl uence of radiogenic lead derived from the basement is higher during mineralization and thus, the isotope ratios rise towards the south. Interestingly, Pb isotopes of mineralizations from the Central Schwarzwald Gneiss Complex and the Southern Schwarzwald Gneiss Complex, two different crustal blocks with a large oceanic suture in between, have signifi cantly different Pb isotope systematics. This fact is explained by the different ages and tectonic origin of the protoliths of the two blocks. a Lead concentration determined by isotope dilution, b

Archaeological and Anthropological Sciences 2, 191-215, Jan 1, 2010

Staude, S., Göb, S. Pfaff, K. Ströbele, F., Premo, W.R., Markl, G. (2011): Deciphering fluid sources of hydrothermal systems: A combined Sr- and S-isotope study on barite (Schwarzwald, SW Germany). Chemical Geology, Vol. 286, Nr.1-2. p.1-20, Jan 1, 2011

Primary and secondary barites from hydrothermal mineralizations in SW Germany were investigated, ... more Primary and secondary barites from hydrothermal mineralizations in SW Germany were investigated, for the first time, by a combination of strontium (Sr) isotope systematics (87Sr/86Sr), Sr contents and δ34S values to distinguish fluid sources and precipitation mechanisms responsible for their formation. Barite of Permian age derived its Sr solely from crystalline basement rocks, whereas all younger barite also incorporate Sr from formation waters of the overlying sediments. In fact, most of the Sr in younger barite is leached from Lower and Middle Triassic sediments.In contrast, most of the sulfur (S) of Permian, Jurassic and northern Schwarzwald Miocene barite originated from basement rocks. The S source of Upper Rhinegraben (URG)-related Paleogene barite differs depending on geographic position: for veins of the southern URG, it is the Oligocene evaporitic sequence, while central URG mineralizations derived its S from Middle Triassic evaporites.Using Sr isotopes of barite of known age combined with estimates on the Sr contents and Sr isotopic ratios of the fluids' source rocks, we were able to quantify mixing ratios of basement-derived fluids and sedimentary formation waters for the first time. These calculations show that Jurassic barite formed by mixing of 75–95% ascending basement-derived fluids with 5–25% sedimentary formation water, but that only 20–55% of the Sr was brought by the basement-derived fluid to the depositional site. Miocene barite formed by mixing of an ascending basement-derived brine (60–70%) with 30–40% sedimentary formation waters. In this case, only 8–15% of the Sr was derived from the deep brine. This fluid-mixing calculation is an example for deposits in which the fluid source is known. This method applied to a greater number of deposits formed at different times and in various geological settings may shed light on more general causes of fluid movement in the Earth's crust and on the formation of hydrothermal ore deposits.► Sr and S isotopes are dependent from stratigrafic position and fluid mixing ratios. ► S isotopes in barite serve to trace an ancient subduction zone at depth. ► Sr isotopic composition of barite are used to quantify fluid mixing ratios. ► Remobilization processes show similar Sr isotopic compositions. ► Remobilization processes show variable S isotopic compositions due to redox conditions.

Conference Presentations by Florian Ströbele

Metalla Sonderheft 8 - Archäometrie und Denkmalpflege 2016

Books by Florian Ströbele

Byzanz zwischen Orient und Okzident, Band 8,1, Aug 2017

The collection of the Badisches Landesmuseum Karlsruhe contains numerous late antique and byzanti... more The collection of the Badisches Landesmuseum Karlsruhe contains numerous late antique and byzantine objects, which were only published in parts hitherto. The artefacts are mainly small finds of high scientific value. Among them are as well sacral as profane objects, passing on a wide range of everyday life, culture and arts in the Late Roman and Byzantine empire. 268 objects of bone, ivory, glass, ceramics, metall and stone, some of them bearing inscriptions, are basically documented, interpreted and classified in cultural history.

Poporadze, N., Kalandadze, O., Seskuria, F., Ströbele, F. (2014) Complex study of the disk and rod found in the Kurgan Ananuri 3. Journal of the Georgian Archaeology, Vol. 22, 216-222

Monographien des Römisch-Germanischen Zentralmuseums, Dec 5, 2013

Neues Jahrbuch für Mineralogie, Abhandlungen, Sep 1, 2012

Archaeological and Anthropological Sciences 2, 191-215, Jan 1, 2010

Byzanz zwischen Orient und Okzident, Band 8,1, Aug 2017