Analysis of the Elemental Composition of Four Bronze Sickles Dated at the Late Bronze Age

. The present study presents the analysis of the elemental composition of four bronze sickles, three with hooked handle and one with holes on the handle, two from the deposit at Valea lui Darie, Vaslui county, one from the bronze deposit at Ciorani, and one discovered in a dwelling from the settlement belonging to the Noua culture from Dodești, following systematic archaeological research. The sickles from the Valea lui Darie deposit belong to the Ghermănești type, the Ghermănești variant, the Ciorani sickle to the Ilișești variant of the Ghermănești type , and the Dodești sickle to the Heleșteni type. These types of sickles are characteristic for the Late Bronze Age east of the Carpathians, being chronologically placed between XII – X BC. The elemental composition of the four pieces was identified by employing non-invasive analysis with a mobile spectrometer, Thermo Niton XL3, resulting in a composition of a binary copper-tin alloy (Cu-Sn), to which a number of secondary elements are added: arsenic, antimony, iron, nickel, lead, titanium, and sulphur. In the case of the sickle from Dodești, the percentage of lead is 1.593% which could come from the composition of the copper or tin ores used, given that the percentage should be higher than 2-3% to be considered an intentional addition. Arsenic was also identified in the composition of the four sickles, but in small percentages, > 1%, most likely coming from the composition of the copper ore used. The elemental composition of ancient artefacts enables the establishment of correlations between different types of objects, production areas, raw material resource areas, and distribution patterns. Based on the elemental composition, the four sickles fall into the group of copper objects with arsenic, antimony/antimony, and nickel as the main secondary elements .


Introduction
In this study we propose to discuss four bronze objects, namely four sickles, belonging to the collections of the Ștefan cel Mare Vaslui County Museum (Fig. 1).Although they have been discussed in various studies on either bronze sickles or bronze deposits, the paper herein approaches a new anngle of investigation by presenting the results of elemental composition analysis.The analysis of metallographic data of different types of bronze objects, including but not restricted to sickles, is a key factor in understanding the metallurgical phenomenon at the End of the Bronze Age.Our results extend a very small collection of reported data recorded on objects from the area between the Carpathians and the Prut, and originating from the end of the Bronze Age, that have been analyzed metallographically2 .
Of the four sickles, three come from hoards and one was discovered isolated.Three of them are sickles with their handle ending in an all-cast hook and are from the Ghermănești type, Ghermănești and Ilieșeni variants, and the fourth with holes on handle, from the Heleșteni type.

Description of the sickles
The first two sickles from Valea lui Darie, Roșiești commune, Vaslui county, come from a bronze hoard discovered accidentally in 1981 in the vicinity of a Noua settlement3 .
The first sickle is complete (Fig. 2), the blade is wide and strongly arched, with rounded tip, the handle is short and ends in a short one-part hook, and the edge presents a prominent line from the extremity of the hook to the tip of the blade, with the role of strengthening the sickle.It was cast in a closed monovalve mould from the handle joining side of the blade, with the casting stub visible, and it was processed after casting by hammering and sharpening.The blade shows usage marks and it is covered with dark green patina.Dimensions: length -234 mm, blade width -35 mm, height of the arch -125 mm, and weight -241 g.Inventory no 15331 4 .
The second sickle presents some differences compared to the first one (Fig. 3).It has a wide, knee-shaped bent blade with rounded tip and the handle is long and ends in a short one-part hook.The edge presents a prominent line from the extremity of the hook to the tip and a second line extending from the base of the hook to the tip, going through the middle of the handle and the blade.It was cast in a closed monovalve mould from the handle joining side of the blade, with the casting stub visible.It was processed after casting by hammering and sharpening.A dark and light green patina covers the entire surface of the object.Dimensions: length -240 mm, blade width -40 mm, height of arch -139 mm, and weight -236 g.Inventory no.153325 .
The third sickle is from Ciorani, Pufești commune, Vrancea county (Fig. 4), and belongs to a bronze hourd consisting of eight pieces: six hooked sickles, one sickle with simple handle and with two holes (the Heleșteni type), and one socketed axe 6 .The blade is narrow and slightly arched, with tapered tip, and the handle is short and ends with a long hook.The object has a prominent line from the extremity of the hook to the tip of the blade on both edges, making a complete contour of the sickle which was never processed after casting.It was cast in a closed monovalve mould from the handle joining side of the blade, with the casting stub visible.The entire surface is covered with brownish green patina.Dimensions: length -150 mm, blade width -25 mm, height of arch -84 mm, and weight -70 g.Inventory no. 9.
The fourth sickle (Fig. 5) is from Dodești, Dodești commune, Vaslui County, and it was discovered in a settlement belonging to Noua culture 7 .The blade is strongly arched and wide, and the handle has two holes for fixing the handle.The edge has a prominent line from the handle to the tip of the blade which has the role to strengthen the sickle.It was cast from the handle joining side of the blade in a one-part closed mould, with the casting stub visible.It was processed after casting by hammering and sharpening, and the blade shows usage marks.The sickle is covered with dark green patina on the entire surface.Dimensions: length -170 mm, blade width -35 mm, height of arch -95 mm, and weight -132 g.Inventory no.1757.
The four sickles are of two different types: three are hooked sickles and one with holes on the handle.The typological and chronological aspects of these types of sickles were discussed in previous studies.Petrescu-Dîmbovița made the first typological classification of the sickles and divided the hooked sickles into seven types 8 .Another typological classification was made by Dergačev, considering the metric parameters in particular 9 .The sickles from Valea lui Darie belong to the Ghermănești type, Ghermănești variant, after Dergačev typology 10 , to the Ghermănești-Ruginoasa type 11 after Petrescu-Dîmbovița typology, and to the C 24 and C 26 types after Cernych typology, respectively, all of them belonging to the hooked sickles from the North-Pontic region 12 .The sickle from Ciorani is of Ghermănești type, Ilieșeni variant, after Dergačev tipology 13 , and of Cristian-Drajna 2 type after Petrescu-Dîmbovița tipology 14 , respectively.Ghermănești type, Ilieșeni variant is characterized by small size and is from the same typological range as Ghermănești and Ruginoasa variant of Ghermănești type.
The sickle from Dodești belongs to the Heleșteni type, Heleșteni variant, after Dergačev typology 15 , and type C 2/4, after Cernych typology 16 .The Ghermănești type sickles are common in Moldova in the Râșești-Băleni hoard series, in Transylvania in the Uriu-Domănești hoard series 17 , while in the early Hallstatt period this type of sickle declines in number and it can be found only during Ha A1 period 18 .The Ghermănești and Ilieșeni variants emerged at the end of the Late Bronze Age, in Br D (XIIth century BC) and developed until the Ha A1 period (Xth century BC).
During the Br D period, hooked sickles were concentrated at the East of Carpathians, whith a lower presence in Transilvanya, a situation that reverses during the Ha A and Ha B, suggesting that these sickles appeared east of the Carpathians and then spread to the neighboring areas.However, there are also hypothesis supporting the appearance of these sickles in Transylvania 19 .Metrical analysis of the three types shows that they are evolutionarily related, evolving from large, large-handled, heavy sickles, to lighter-weight, smaller-handled sickles that required less raw material for casting 20 .
The Heleșteni type, Heleșteni variant has no prototype and emerged in the Noua culture area, being produced in the Prut-Dniester interfluve from where it expanded to the East in the Sabatinovka culture.The Heleșteni sickles are dated to the Br D -Ha A1 (XIIth century BC -Xth century BC).

Methods of Analysis
The four sickles were investigated through nondestructive X-ray fluorescence analysis with a portable spectometer, Thermo Niton XL3, using a Si-PIN diode and a 50 kV voltage for X-ray excitation, 40 µA, 2 Watt max.In order to perform the measurements, a surface of 1 square cm of patina was cleaned.The depth of the analysis was 0,01 mm, therefore the recorded data show the elemental composition status of the surface layer of the pieces only.Measurement data were processed with Thermo Nito, a program developed by the device manufacturer.The spectrometer can identify a number of 30 chemical elements, but some elements were indentified below the limit of detection and their concentration could not be quantified.Thus, the elements indicated as <LOD> by the software were not included in our analysis.
For each element identified, the software adds to the database the analysis error, which is helpful when the data is centralized, analyzed, and corroborated with other data.

Results and Discussions
Analysis of the four sickles has shown that the objects are made of bronze, binar copper -tin alloy, with values of tin ranging between 0,179% and 12,01%.The sickles from Ciorani and Dodești have values of tin of 10,806% and 12,01%, respectively, which is within the normal ratio of copper and tin for bronze (90+10%).In the case of the sickles from Valea lui Darie, the percentage of Sn is extremely small, 1,068% and 0,179%, which is unusual but not unique.In the elemental analysis made by E. N. Cernych, there are twelve bronze sickles with tin concentrations between 0,015% and 2%, all of them from bronze hoards: Knjaze-Grigorovka, Becilovo, Rajgorodka, Orekhovo (Ukraine) 21 .From the Ulmi-Liteni hoard there is a hooked sickle with 0,35% tin in composition22 .Usual content of tin in copper-tin alloys is around 10%, which could be an indication that the artefact is not recycled but at the primary alloy.When tin is found in alloys in small percentages, around 2% and even below 1%, it could be a sign of recycling of bronzes with different tin levels 23 .The most important source of tin is cassiterite (SnO2), and the closest source apears at Băile Borșa, Maramureș county, at Burloaia, Măgura, Gura Băii, Izvoru Ursului, and Toroiaga veins 24 .Another source that could have been used is stannite (Cu2FeSnS4) which is a sulfide mineral of copper, iron, tin, and sulphur (28% tin, 12% iron, 30% copper, 30% sulphur) and occurs with chalcopyrite, tetrahedrite, and could be used to obtain a copper -tin alloy.This mineral is rare and has been identified at Băile Borșa, Burloaia and Izvoru Ursului veins25 , Valea lui Stan, Vâlcea county, Hondol, Pârâul lui Avram -Livia veins, Hunedoara county, here being associated with chalcopyrite and tetrahedrite 26 .It is hard to believe that upon obtaining this type of alloy, the ancient metallurgists would have left it at this stage to make the two sickles.
All four sickles contain arsenic as a trace element and is difficult to say whether they come from recycling arsenical bronze objects or that minerals containing copper and arsenic were used.It is well known that arsenic losses under oxidizing condition, which occurs during solidification and in smaller scale during melting and puring in moulds 27 .The sickle from Dodești (read no 1971) contains a small percentage of Pb, 1,593%, that could come from lead impurities in copper or tin ore residues, since an intentional alloy of lead should be considerated only when it is above 2%.
Correlation between chemical composition af ancient bronze artefacts and geological sources of metal through trace elements is difficult to establish since it requires a large number of analysis from all known copper deposits.Furthermore, re/melting of metals makes it difficult to relate an object to a specific ore source.
The copper ores that could have been used by metallurgists from the region between Carpathians and Pruth at the Late Bronze Age are in the Carpathian Mountains and Măcinului Mountains, where accumulations of copper sulphosalts, sulphates, carbonates and oxides were present 28 .To carry out an analysis of the link between the bronze artefacts and resource areas, two minimum conditions must be met: the existence of elemental composition analysis of bronze artifacts and analysis of the chemical composition of copper ores.An increase in the number of elemental composition analyses for artefacts is ongoing.However, analyses on ores are very rare 29 and thus, the two conditions are not met.
One usseful tool to be used in provenancing copper ores is Pb isotopic analysis, but this method has its limitations since some objects have lower levels of Pb than required to obtain isotopic analysis results 30 .Using Cu and Sn isotopic information is also a possibility to trace a bronze artifact to the original ore source 31 , but there is no absolute technique of direct provenance in bronze metallurgy.An ancient bronze artefact has a long journey which starts with extracting copper and tin ores, casting the material in different forms of ingots later transformed into various objects which are being used, re/melted, repurposed, and finally deposited.The time between origin and deposition of the object is dependent on the social and economic context 32 .
Bray considers that interpreting trace elements of copper could be done through the presence/absence of four elements: arsenic, antimony, silver, and nickel, which are the most common in ores.Using this metod ancient bronze objects could be included in so-called copper groups which are not necessarily related to a specific ore source but rather to the geographical distribution of these artifacts over a certain period 33 .Using this method, the four sickles can be included in group 14, copper with arsenic (As), antimony (Sb) and nickel (Ni).In the future, using more data, a statistical analysis regarding the distribution and connections between the copper groups in a certain areal can be made and, if chemical analyses of copper ores exist, relations between ores centres and copper groups could be established.

Conclusions
This paper analyzes four sickles, three with hocked handle and one with holes on the handle, whose elemental composition was determined using a portable X-ray fluorescence spectrometer (XRF).This noninvasive technique yields information about the elemental composition of the objects, but only at the level of the surface layer, were patina was removed, and enables rapid and inexpensive analysis of multiple objects.Three of the four sickles have wear traces, except the one from Ciorani that was never used, and all four were discovered in so-called closed complexes.
Elemental composition revealed that all four sickles have arsenic traces which could be explained by the use of sulphidic copper ores, possible tetraehidrite.The recycling of bronze artifacts is attested in the sickles from Valea lui Darie, being the most plausible explanation for the small percentage of tin in their composition.