<abstract xmlns="http://www.w3.org/1999/xhtml">Numerous ruins around the world lack the radiometric dating due to the scarcity of organic carbon. Here, we present results of radiocarbon dating of mortar samples from an early Medieval church Hohenrätien GR, Switzerland, which was dated to the early 6th century, based on typology. The method of dating mortars, which is currently applied at the ETH laboratory, involves sieving the crushed mortar, selection of grain size 45−63 μm and sequential dissolution resulting in four fractions of CO2 collected in a 3-second interval each. Two mortar samples, which were analyzed using sequential dissolution and one by dating a bulk of lime lump, resulted in a combined radiocarbon age of 1551±21 BP translating to the calendar age of 427−559 AD.</abstract>

Numerous ruins around the world lack the radiometric dating due to the scarcity of organic carbon. Here, we present results of radiocarbon dating of mortar samples from an early Medieval church Hohenrätien GR, Switzerland, which was dated to the early 6th century, based on typology. The method of dating mortars, which is currently applied at the ETH laboratory, involves sieving the crushed mortar, selection of grain size 45−63 μm and sequential dissolution resulting in four fractions of CO2 collected in a 3-second interval each. Two mortar samples, which were analyzed using sequential dissolution and one by dating a bulk of lime lump, resulted in a combined radiocarbon age of 1551±21 BP translating to the calendar age of 427−559 AD.

14C Dating of mortar from ruins of an early medieval church Hohenrätien GR, Switzerland

Geochronometria

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

C Dating of mortar from ruins of an early medieval church Hohenrätien GR, Switzerland

Numerous ruins around the world lack the radiometric dating due to the scarcity of organic carbon. Here, we present results of radiocarbon dating of mortar...

Lab Code	Sample/Fraction (μm)	Dissolution time (s)	¹⁴C age ±1 sigma (BP)	Calibrated age (95.4% conf. level) (AD)	μg C
ETH-65530	891, 45−63	1−3	1534±84	348−656 AD	95
ETH-65530	891, 45−63	4−6	1688±88	NA	109
ETH-65530	891, 45−63	7−9	2108±102	NA	108
ETH-65530	891, 45−63	10−12	2621±101	NA	104
ETH-65530	891, 32−45	1−3	1605±74	257−606 AD	60
ETH-65530	891, 32−45	4−6	1737±83	NA	105
ETH-65530	891, 32−45	7−9	2144±103	NA	88
ETH-65530	891, 32−45	10−12	2461±105	NA	96
ETH-69913	894, 45−63	1−3	1386±64	543−770 AD	81
ETH-69913	894, 45−63	4−6	1581±63	NA	99
ETH-69913	894, 45−63	7−9	1664±77	NA	91
ETH-69913	894, 45−63	10−12	2254±76	NA	82
ETH-85506	897, LL (lime lumps)	Total dissolution	1569±24	422−547 AD	1200 graphite
Combined	891 & 894	all 1−3 s	1495±41	430−646 AD	X2-Test: df=2 T=5.3 (5% 6.0)
Combined	891 & 894 & 897	all 1−3 s & LL	1551±21	427−559 AD	X2-Test: df=3 T=7.7 (5% 7.8)

¹⁴C Dating of mortar from ruins of an early medieval church Hohenrätien GR, Switzerland

Article Category: CONFERENCE PROCEEDINGS OF THE 13TH INTERNATIONAL CONFERENCE “METHODS OF ABSOLUTE CHRONOLOGY” JUNE 5-7TH, 2019, TARNOWSKIE GORY, POLAND

Published Online: Dec 31, 2020

Page range: 118 - 123

Received: Dec 16, 2019

Accepted: May 29, 2020

DOI: https://doi.org/10.2478/geochr-2020-0027

Keywords
Archaeology, early Medieval, mortar, radiocarbon dating

© 2020 I. Hajdas., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig 1a

Fig 1b

Fig 2

Fig 3

Fig 4

Fig 5

Results of the 14C AMS analysis of mortar samples. All the samples but lime lump (LL) were analyzed using GIS. Combined and calibrated ages were obtained using OxCal v4.3.2 (only for 14C ages evaluated as accurate).

14C Dating of mortar from ruins of an early medieval church Hohenrätien GR, Switzerland

Article Category: CONFERENCE PROCEEDINGS OF THE 13TH INTERNATIONAL CONFERENCE “METHODS OF ABSOLUTE CHRONOLOGY” JUNE 5-7TH, 2019, TARNOWSKIE GORY, POLAND

Published Online: Dec 31, 2020

Page range: 118 - 123

Received: Dec 16, 2019

Accepted: May 29, 2020

DOI: https://doi.org/10.2478/geochr-2020-0027

KeywordsArchaeology, early Medieval, mortar, radiocarbon dating

© 2020 I. Hajdas., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig 1a

Fig 1b

Fig 2

Fig 3

Fig 4

Fig 5

Results of the 14C AMS analysis of mortar samples. All the samples but lime lump (LL) were analyzed using GIS. Combined and calibrated ages were obtained using OxCal v4.3.2 (only for 14C ages evaluated as accurate).

¹⁴C Dating of mortar from ruins of an early medieval church Hohenrätien GR, Switzerland

Keywords
Archaeology, early Medieval, mortar, radiocarbon dating