Luminescence dating of mortar and terracotta from a Royal Tomb at Ulaankhermiin Shoroon Bumbagar, Mongolia

Abstract

The spectacular royal tomb "Ulaankhermiin Shoroon Bumbagar" was discovered in Bulgan province, Mongolia, in 2011. Excavation of the site revealed its internal structure; a slope of 42 meters in length leading down to the underground mausoleum at a depth of 7 m below the ground. Archaeological investigations provided the site with an independent age control suggesting the construction date of the Royal tomb to the last quarter of the VII century. In this study, we directly date different materials from the site, such as terracotta figurines, mortar and host sediment, using infrared-stimulated (IR 50) and postinfrared infrared stimulated (pIRIR) luminescence techniques. The most accurate estimate of 670^70AD and 550^110AD was obtained for terracotta figurines using IR 50 and pIRIR on aliquots of 4-11 mm polymineral grains. By comparison, sand-sized quartz single grain measurements on the embedded sediment yielded normal equivalent dose (D e) distributions with a few outliers, justifying the use of the central age model (CAM) for age calculation, and yielded construction dating to the 780^140AD. Finally, sand-sized quartz single grain measurements on wall mortar revealed incomplete bleaching of grains, requiring detailed analysis using statistical approaches; from this we identified the most well bleached population age of 740^130AD, using the lowest 5%. The luminescence ages are in general agreement with the historically expected age. Statement of significance The archaeological site at Ulaankhermiin Shoroon Bumbagar, Mongolia (with an independent age control) offers a great opportunity to apply luminescence dating methods, such as pIRIR on 4-11 mm polymineral fine grains, and single grain measurements on 200-250 mm quartz grains, to various materials, such as terracotta figurines, mortar-like limestone which covered the walls and embedded sediment in order to test the accuracy of optically stimulated luminescence (OSL) dating techniques. Compared to all other datable archaeological materials, mortar has the advantage of being intentionally manufactured at each stage of construction, since it cannot be recycled. However, dating of the well bleached grains of mortar, which provided the greatest challenge in this study, was achieved using the lowest 5% estimate, yielding an age of 740^130AD. pIRIR on heated polymineral (feldspar-bearing) fine grain aliquots from terracotta figurines was tested, yielding IR 50 and pIRIR 180 dates in agreement with the CAM estimate from the host sediment.

Multimethod characterization of terracotta figurines and lime mortar from the elite burials Shoroon Bumbagar I and II, Mongolia

“…The similarity of both archaeological sites suggested a date close to 679 AD, based on information from the epitaph on SB‐I. The scientific dating based on the optically stimulated luminescence method gave dates for the production of terracotta and the construction of tomb murals as 670±70 AD and 740±130 AD, respectively (Solongo et al, 2016; Solongo & Ochir, 2016). Data 659–682 AD is the 23‐year gap between the fall of the First and the rise of the Second Kagan of Köktürks, which in turn is the historically expected date for construction of SB‐II (Steinhardt et al, 2020).…”

The polymorphism and tradition of funerary practices of medieval Turks in light of new findings from Tuva Republic

“…The singular royal tombs of the shoroon bumbagar form (translated as ‘earthen rotundity’ by Christopher Atwood in [ 37 ]) in Bayanuur sum (Bulgan aimag) and Zaamar sum (Töv aimag), dated to 7 th -early 8 th century ([ 37 ]; for optically stimulated luminescence (OSL) dates of terracotta and mortar samples from Bayannuur, see [ 40 ]), contain evidence of architectural and decorative murals, clay figurines, and coinage that reflects the percolation of Chinese burial rituals into Turkic funerary practice as the Tang Empire took increasing control over the heartland of the previous Eastern Turk empire.…”

Efeito Da Compactação Mecânica Na Intensidade Termoluminescente Do Quartzo E Da Calcita

“…A hipótese de uma moagem mais severa parte do pressuposto de que, nos protocolos de datação geológica ou arqueologia, muitas vezes, se recomenda o uso de material particulado com grãos finos. A datação com o uso de minerais particulados finos, cujos diâmetros variam entre 1 e 8 µm, foi sugerida no passado e continua sendo utilizada em estudos mais recentes (SEELEY, 1975;SOLONGO et al, 2016).…”