INTRODUCTION
Accelerator mass spectrometry (AMS) activities at IUAC started with its 15UD Pelletron accelerator and cosmogenic radionuclides (CRN) 10Be and 26Al were measured (Kumar et al. Reference Kumar, Pattanaik, Ojha, Gargari, Joshi, Roonwal, Balakrishnan, Chopra and Kanjilal2011, Reference Kumar, Chopra, Pattanaik, Ojha, Gargari, Joshi and Kanjilal2015). Realizing the demand of a radiocarbon (14C) AMS facility in India, a 500kV Pelletron accelerator-based AMS system was installed in 2015 and the facility was designated with the lab code IUACD for 14C measurements. 14C dates measured in the years 2015 and 2016 were published in the first IUACD date list (Sharma et al. Reference Sharma, Kumar, Ojha, Gargari and Chopra2020). We present here the second 14C date list, which consists of dates measured from January to December 2017. In 2015, we started with one automated graphitization equipment (AGE) unit in the sample-preparation laboratory (graphitization laboratory) and 500 kV Pelletron accelerator (XCAMS: the Compact 14C Accelerator Mass Spectrometer eXtended for 10Be and 26Al) for AMS measurements. In 2017, two more AGE units and one carbonate handling system (CHS) were installed in the graphitization laboratory to increase the sample throughput. A carbonate handling system is utilized for the acid hydrolysis of carbonate samples and produced CO2 is graphitized using one of the three AGE. This leads the starting of 14C measurements of carbonate samples. Sample pretreatment protocols, graphitization procedures, measurement regimes, and data analysis procedures of IUAC 14C dating laboratory have already been reported in Sharma et al. (Reference Sharma, Umapathy, Kumar, Ojha, Gargari, Joshi, Chopra and Kanjilal2019, Reference Sharma, Kumar, Ojha, Gargari and Chopra2020).
In brief, samples were first visually inspected under microscope for visible contaminations (roots, hair, thread, etc). Sediment, charcoal, brick samples were subjected to acid–base–acid (ABA, 0.5M HCl, 0.1M NaOH) protocol and wood samples were subjected to base–acid–base–acid–bleaching (BABAB, 4% HCl, 4% NaOH, 5% NaClO2 with few drops of 4% HCl) protocol (Nemec et al. Reference Nemec, Wacker, Hajdas and Gäggeler2010). Pretreated samples were freeze dried and combusted in the elemental analyzer (EA) and produced CO2 is graphitized in the coupled graphitization unit of AGE system. Shell samples were also leached with 0.1M HCl and produced CO2 is flushed with helium gas. Leached samples were then hydrolyzed with 85% phosphoric acid in CHS and graphitized using AGE. Graphite samples were measured using XCAMS and measured ratios were normalized with OXII standard and δ13C value = −25‰. Secondary standard samples (IAEA C1, C2 for carbonate samples, C3, C4, C5, C9 for wood samples, C7, C8 for other organic samples) were used for quality control. Data was analyzed using NEC abc software and 14C ages (BP) were calculated as per the method described in Stuiver and Polach (Reference Stuiver and Polach1977).
Archeological Samples
Charcoal, wood, and sediment samples were collected by Mr. Mudit Trivedi, University of Chicago, Chicago, USA from an archaeological site Indor (District – Alwar, Rajasthan) and submitted to IUAC for 14C dating.
Samples from early Holocene prehistoric camping site (34º56ʼ31"N, 77º31ʼ46"E) were collected and submitted to IUAC by Dr. S. B. Ota, ASI, New Delhi. This site lies about 22 km on the road leading to Saser La Top from village Sasoma in Nubra Valley, Ladakh. Two localities very close to each other were excaveted at this site and collected samples for AMS 14C dating were numbered under SSM and two localities have been numbered as L1 and L2. The associated cultural remains (lithic artifacts and bone artifacts) found at this site indicate the early domestication of animals.
Samples collected from Binjor, Rajasthan (29º13ʼ25"N, 73º07ʼ38"E) were submitted to IUAC by Dr. Sanjay Kumar Manjul, Institute of Archaeology, ASI, New Delhi.
Charcoal samples collected from Karanpura, District Hanumangarh (Rajasthan) (29°5ʼ24"N, 75°5ʼ24"E) and Dholavira, District Kachchh (Gujarat) (23°31ʼ48"N, 70°7ʼ48"E) were submitted by Dr. V. N. Prabhakar, ASI, New Delhi.
Karanpura Series
Dholavira series
Charcoal and shell samples from Erenda, East Medinipur district, West Bengal (21°55ʼ4.8"N, 87°34ʼ42.4"E) were submitted by Dr. Kaushik Gangopadhyay, University of Calcutta, Calcutta. Radiocarbon dates validate the proto-historic phase of this site that is suggested by the excavated artifacts (Naskar et al. Reference Naskar, Chaudhuri, Gangopadhyay, Ghosh, Lahiri, Sharma, Kumar, Ojha and Chopra2018; Kumar Das et al. Reference Kumar Das, Gangopadhyay, Ghosh, Biswas, Bera, Ghosh, Paruya, Naskar, Mani, MS and Yoshida2021).
Brick samples from the archaeological site of Nalanda Mahavihara (25.13712ºN, 85.44325ºE) Nalanda, Bihar from three unprotected archaeological mounds, Begampur, Baragaon and Kapatia Mounds were submitted to IUAC by Dr. M. B. Rajani, National Institute of Advanced Studies (NIAS), Bangalore. These brick samples were powdered and dated as sediments (Das et al. Reference Das, Kumar, Rajni and Chopra2019). As described in the Indian history, Nalanda Mahavihara was a Buddhist monastry that was active in the period from 4th–5th century AD to 12th century AD (Das et al. Reference Das, Kumar, Rajni and Chopra2019).
Begampur Mound
Baragaon Mound
Kapatia Mound
Samples from various sites from Haryana, North India were submitted by Prof. A. R. Chaudhary, Centre of Excellence for Research on the Saraswati River, Kurukshetra University, Kurukshetra. Using radiocarbon dates, satellite imagery, shuttle radar topography mission data and optically stimulated luminescence dates, submitters identified the paleo path of ancient river (Saraswati) and also conclude that there was flow of water through this channel until AD 1402 (Chaudhri et al. Reference Chaudhri, Chopra, Kumar, Ranga, Singh, Rajput, Sharma, Verma and Sharma2021). Twelve radiocarbon dates given blow (except for samples IUACD#17C1274 and IUACD#17C1275) were used for this study (Chaudhri et al. Reference Chaudhri, Chopra, Kumar, Ranga, Singh, Rajput, Sharma, Verma and Sharma2021).
Mugalwali (30°23ʼ41"N, 77°19ʼ28"E)
Bhaur Sayidan (29°57ʼ38"N, 76°42ʼ06"E)
Geological Samples
Sediment, shell and wood samples from three cores (Core B, C, D) Coringa Wild life Sanctuary, Andhra Pradesh were submitted by Ms. Namrata Priya, JNU, New Delhi.
Core B (16°52ʼ40.74"N, 82°16ʼ52.20"E)
Sediment Samples
Core C (16°49ʼ21.50"N, 82°19ʼ46.40"E)
Sediment Samples
Core D (16°47ʼ44.70"N, 82°15ʼ31.00"E)
Sediment Samples
Wood Sample
Sediment and shell samples from different sites were submitted by Prof. Hema Achyuthan, Anna University, Chennai, India (Lone et al. Reference Lone, Achyuthan, Shah, Sangode, Kumar, Chopra and Sharma2020; Shah et al. Reference Shah, Achyuthan, Lone, Kumar, Kumar, Sharma, Amir, Singh and Dash2020, Reference Shah, Achyuthan, Lone, Kumar, Ali and Rahman2021).
Western margin of the Wular Lake (34º20.639ʼN, 74º30.669ʼE)
Sediment Samples
New Wular Core (NWC) from Wular Lake (34.3666°N, 74.5344°E)
Sediment Samples
Sediment core from Wular Lake (34°22ʼ5.80"N and 74°32ʼ8.39"E)
Sediment Samples
Chilka Lake (85°11.965ʼE, 19°42.879ʼN)
Shell Samples
Sediment Samples
Anchor Lake (34°08ʼ37.58"N and 74°47ʼ10.89"E)
Sediment Samples
Shell Sample
Makaibagh Section, Ganderbal (34º12ʼ10.01"N, 74º48ʼ39.56"E), Central Kashmir Valley
Sediment Samples
Wular Lake (34°22ʼ36.90"N, 74°31ʼ52.24"E)
Sediment Samples
Jejuri Lake (18.2766°N, 74.1622°E)
Sediment Samples
Perumal Lake samples (11.5667°N, 79.6833°E)
Sediment Samples
Pine wood samples were collected from various lcations and submitted to IUAC by Prof. Milap Chand Sharma, JNU, New Delhi (R. Saini et al. Reference Saini, Sharma, Deswal, Barr, Kumar, Kumar and Chopra2019).
Pine Wood Samples
Patam (32°53.342ʼN, 76°52.970ʼE, altitude: 3681 m)
Patam (32°53.342ʼN, 76°52.975ʼE, altitude: 3681 m)
Tharang (32°53.845ʼN, 76°53.210ʼE, altitude: 3738 m)
Tharang (32°53.848ʼN, 76°53.210ʼE, altitude: 3737 m)
Tharang (32°53.850ʼN, 76°53.210ʼE, altitude: 3738 m)
Sediment samples were collected from Shankerpora (33°50ʼ504"N, 74°47ʼ726ʼʼE) and Burzahma (34°10ʼ279"N, 74°52ʼ242ʼʼE), Kashmir, India and submitted to IUAC by Prof. J. P. Srivastava, Delhi University, New Delhi (Meenakshi et al Reference Meenakshi, Shrivastava, Chandra, Chopra, Roonwal and Sharma2018).
Shankerpora (33°50ʼ504ʼʼN, 74°47ʼ726ʼʼE), height of each sample above sea level (asl) is given in the bracket with submitter ID.
Sediment Samples
Burzahma (34°10ʼ279"N, 74°52ʼ242"E), height of each sample above sea level (asl) is given in the bracket with submitter ID.
Sediment Samples
Sediment samples from two cores (Dhordo core and Berada core) from the Great Run of Kachchh, were submitted by Mr. Abhishek Kumar, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, India.
Dhordo Core (23°49ʼ37.9"N, 69°39ʼ9.0"E)
Sediment Samples
Berada Core (23°28ʼ29.12"N, 69°54ʼ36.84"E)
Sediment Samples
Sediment samples collected from different sites Dokirini, Tibet, Bhujbhasa and Tapovan and submitted by Ms. Ipsita Roy and Dr. P. S. Ranhota, BSIP, Lucknow.
Dokriani (30º51ʼ1.6"N, 78º44ʼ58.2"E)
Sediment Samples
Tibet (31º53ʼN, 91º42ʼE)
Sediment Samples
Bhujbhasa (30º45ʼ–31º15ʼN, 78º54ʼ–79º17ʼE)
Sediment Sample
Tapovan (30º54ʼ36.40"N, 79º04ʼ30.66"E)
Sediment Sample
Charcoal and sediment samples from various locations were submitted by Prof C. P. Rajendran, JNCASR, Banglore.
Kelshi, Maharashtra (17º55ʼ39.9288"N, 73º3ʼ29.106"E)
Charcoal Samples
Sediment Sample
Wandur, Andaman (11º35ʼ33.8028"N, 92º36ʼ46.5516"E)
Charcoal Sample
Sediment Samples
Imadhol, Nepal (27º39ʼ48.7944"N, 85º20ʼ38.3604"E)
Sediment Sample
Samples from two cores (GC1 and GC2) collected from off Lakshadweep islands and off Goa during 2015 by the Ministry of Earth Sciences research vessel Sagar Kanya were submitted to IUAC, New Delhi by Neelvannan, University of Madras (Neelavannan et al. Reference Neelavannan, Hussain, Nishath, Achyuthan, Veerasingam, Prakasam, Kumar, Singh and Kurian2021).
GC1 Core (13º04ʼ5.50"N, 70º56ʼ10.21"E)
Sediment Samples
GC-2 Core (15º00ʼ18.92"N, 72˚26ʼ34.48"E)
Sediment Samples
Samples from Northwest Himalaya were submitted to IUAC, New Delhi by Prof. J. N. Malik, Indian Institute of Technology (IIT) Kanpur.
Thapli (30°44ʼ36.03"N, 77°0ʼ28.50"E), Northwest Himalaya
Charcoal Samples
Tipra-Near Pinjore Dun (30°48ʼ47.48", 76°55ʼ53.39"), Northwest Himalaya
Charcoal Samples
Chilika Lagoon Core (19°28ʼ–19°54ʼN and 85°05ʼ–85°38ʼE) (Amir et al. Reference Amir, Paul and Malik2021)
Sediment Samples
Samples from Eastern Himalaya were submitted by Dr. Jayan Perumal, Wadia Institute of Himalayan Geology (WIHG), Dehradun, India.
Bara Chenga, Darjeeling, West Bengal, India (26°47ʼ07.5"N, 88°12ʼ59.3"E)
Charcoal Samples
Ultapani, Kokrajhar, Assam, India (26°43ʼ40.86"N, 90°18ʼ6.84"E)
Charcoal Samples
Ultapani, Kokrajhar, Assam, India (26°43ʼ59"N, 90°18ʼ08"E)
Charcoal Sample
Kaniyasot, Ramnagar, Uttarakhand, India (29°23ʼ56.81"N, 79°05ʼ14.622"E)
Charcoal Sample
Bara Chenga, Darjeeling, West Bengal, India (26°47ʼ10.56"N, 88°12ʼ57.76"E)
Charcoal Sample
Samples from Central Himalaya were submitted by Dr. Paul Tapponnier, NTU, Singapore.
Nattusaur-Gujjar Village (29.856045°N, 78.336913°E), Central Himalaya
Charcoal Samples
Nattusaur-Gujjar Village (29.858480°N, 78.337113°E), Central Himalaya
Charcoal Samples
Nattusaur-Gujjar Village (29.855518°N, 78.338132°E), Central Himalaya
Charcoal Samples
Samples from Haryana, India were submitted by Prof. N. C. Pant, Delhi University (DU), New Delhi.
Ikkas (29°17ʼ17.88"N, 76°17ʼ29.04"E), Haryana
Ash Samples
Sediment Samples
Uglan Khera (29°09ʼ22.2"N, 76°15ʼ56.2"E), Haryana
Ash Samples
Sediment Samples
Sediment samples from Chandratal lake (32°29ʼ43"N, 77°36ʼ48"E) Western Himalaya were submitted by Mr. Om Kumar, Jawaharlal Nehru University (JNU), New Delhi (Kumar et al. Reference Kumar, Ramanathan, Bakke, Kotlia and Shrivastava2020, Reference Kumar, Ramanathan, Bakke, Kotlia, Shrivastava, Kumar, Sharma and Kumar2021; Shamurailatpam et al. Reference Shamurailatpam, Kumar and Ramanathan2021).
Sediment Samples
Sediment samples from various locations were submitted by Dr. Sandhya Mishra, BSIP, Lucknow.
Khonoma Village (KHN, 25°38ʼ26.9"N, 94°01ʼ05.4"E), Nagaland, India
Charcoal Sample
Sediment Samples
Viswema (VMV, 25°38ʼ58.7"N, 94°01ʼ24.5"E), Nagaland, India
Sediment Samples
Sediment and shell samples from various locations from Gangotri Glacier, Garhwal Himalaya and arctic were submitted by Prof. Dhruv Sen Singh, University of Lucknow (Singh et al. Reference Singh, Dubey, Kumar, Kumar and Ravindra2018, Reference Singh, Dubey, Kumar, Vishawakarma, Singh, Tripathi, Gautam, Bali, Agarwal and Sharma2019).
GKA 16 trench (30°56′55.4″N, 79°03′34.9″E), GKB 16 trench (30°56′54.7″N, 79°03′35″E) and GKA 15 trench (30°57′00″N, 79°03′28″E)
Sediment Samples
GKB trench (30°57ʼ02"N, 79°03ʼ31"E)
Sediment Samples
GBO Trench (30°56ʼ59.2"N, 79°03ʼ01"E)
Sediment Sample
GRA Trench (30°56ʼ57.6"N, 79°03ʼ4.6"E)
Sediment Samples
GLC Trench (30°56ʼ13.2"N, 79°04ʼ7.7"E)
Sediment Samples
GLA Trench (30°56ʼ22.7"N, 79°03ʼ54.8"E)
Sediment Samples
Arctic Samples (78°56ʼ88"N, 11°48ʼ885"E)
Sediment Samples
Shell Sample
Samples from two sediment cores (Chilka lake and Anshupa lake) from Odisha coast were submitted by Chinmay Das, Indian Institute of Technology Roorkee (IITR) (Das et al. Reference Das, Dhal, Kumar, Pati and Chopra2021).
Anshupa Lake Core (85°86ʼE and 20°32ʼN)
Sediment Samples
Chilka Lake Core
Sediment Samples
Shell Sample
Wood and sediment samples from Sundarbans, West Bengal were submitted by Prof. Punarbasu Chaudhary, Calcutta University, Calcutta.
Gosaba, West Bengal
Wood Sample
Godkhali
Wood Sample
Sediment Samples
Lothian, West Bengal
Wood Samples
Samples from Sandynallah valley situated in Nilgiris Massif between 11°26ʼ32"N, 76°38ʼ6"E and 11°26ʼ37"N 76°38ʼ8"E, Southern Western Ghats, India were submitted by Dr. P. Ramya Bala, IISC, Bangalore (Kavil et al. Reference Kavil, Ramya Bala, Kumar, Ghosh and Sukumar2021).
Peat Samples
Sediment samples from Indian Sundarbans, West Bengal were submitted by Dr. Neera Sen Sarkar, Kalyani University, West Bengal.
Bally Island (Core 2) (22°5ʼ32.2"N, 88°45ʼ28.9"E)
Jharkhali (Core 1) (22°1ʼ08.7"N, 88°41ʼ03.1"E)
Sediment Samples
Samples from Renuka lake and Rewalsar Lake, Himachal Pradesh, India were submitted by Dr. N. K. Meena, WIHG, Dehradoon, India.
Renuka Lake (30°36ʼ36"N, 77°27ʼ45"E), Sirmour District, Himachal Pradesh, India
Rewalsar Lake (31.63389°N, 76.83333°E, Elevation: 1360 m), Himachal Pradesh, India
Environmental Samples
Tree leaves and carbonate samples from a location (14°52ʼ55"N, 74°21ʼ19"E) near to Kaiga nuclear power plant and premises of the Centre for Advanced Research in Environmental Radioactivity (CARER), Mangalore University (12°49ʼ02"N, 74°55ʼ18"E) were submitted by Prof. Karunakara. N, Mangalore University, Mangalore. These samples were used to estimate environmental radioactivity. Therefore, results were provided to the user in the form of pMC values (Bharath et al. Reference Bharath, Arya Krishnan, D’Souza, Rashmi Nayak, Ravi, Sharma, Kumar, Chopra and Karunakara2021).
Carbonate Samples
ACKNOWLEDGMENTS
The authors are thankful to the Pelletron group members for providing their expertise to ensure the XCAMS operated smoothly. The authors also thank the Ministry of Earth Science (MoES), Govt. of India for providing financial support (reference numbers: MoES/16/07/11(i)-RDEAS and MoES/P.O.(Seismic)8(09)-Geochron/2012) for the establishment of the AMS facility at IUAC, New Delhi.
