Argon-argon geochronology facility
This facility for 40 Ar - 39 Ar ges and thermo chronology is a multicollector noble-gas mass spectrometer.This facilitates dating it variety of samples that contain reasonable amounts of potassium.
Make and Model
Thermo Scientific Argus VI
Available mode for use
Multi collector mode
Peak switching ion counting mode
Controlled heating at variable temperaturesup to 1800 degree Celsius
Used for bulk sample analysis.
A vacuum crushing system for analyzing trapped gases.
Types of samples:
- Whole rock
- Mineral ensemble
- Single grain
- Fluid inclusions
The Gas extraction systems:
- Conventional dual vacuum resistance heating
- Laser ablation and laser heating
- In situ vacuum crushing
Geo and thermochronology
Fluid and melt inclusion studies
Contact Emailargon[dot] geos[at] iitb[dot] ac[dot] in
Contact no.+91 22 2576 4263
Location (Address)Argon Laboratory, Room No. 13,
Department of Earth Sciences,
I.I.T. Bombay, Powai,
Mumbai - 400076
- ARGUS-VI specifications:
- The ARGUS VI system is an extended geometry 13 cm radius 90o magnetic sector analyzer with ultra low internal volume of 600 cc.
- Mass Range: 0 to 50 amu at 4.5 kV acceleration voltage
- Background: > 5 X10-14 cc STP (@m/z 36Ar)
- Sensitivity: 1 X 1012femto Ampere/ torr @ 200 micro Ampere source current at 4.5 KV
- Resolution: >200@ Axial (38Ar) Faraday Cup.
- System Stability: < ± 50 ppm/30 minutes
- Peak top Flatness Faradays ≤ ± 0.001 for ±150 ppm (mass deviation) @ Ax (38Ar)
- Peak side stability: Drift to be less than the equivalent of ±50 ppm in mass over 30 minutes at mass 40
- Rate of rise: Rate of rise at mass 40 to be less than 1 x 10-12 cc STP/min of Argon 40 over 30 minutes
- Abundance sensitivity: <5 ppm for adjacent mass (39 contribution from 40) at pressure of 1 x 10-7 mbar
- Peak flat: Axial Faraday peak flat will be equal or better than ± 1 in 1x103 over ± 150 ppm in mass
- Pumping: Diaphragm Pump supported by 70 litres / second Turbo Pump, Ion pump: 20 Litres/second
- Getter: SAES NP10 - Zr/Al non-evaporable getter pump
Pneumatic / manual valves have helium leak rates for valve and body < 1 x 10-10cc STP/sec
Heaters and controls to bake mass spectrometer to > 300 oC
Detectors: 5 Faraday Cups
The collector array incorporates five Faraday detectors fitted to allow the true simultaneous collection of masses 36, 37, 38, 39 and 40. These Faraday cups incorporate new high gain amplifier circuits that allow for gains of 1010, 1011 or 1012 to be used. The temperature controlled evacuated amplifiers have an extended measurement range of 50 volts, rather than the historical 10 volts, giving a much wider dynamic range.
Multiplier Performance Details: This new compact discrete dynode (CDD) electron multiplier has an ion counting efficiency > 80 % with inherent noise < 10 cpm and has been designed specifically for very low out gassing rates.
- Dynamic range: 1 cps to 1,400,000 cps
- Linearity: < 0.2 % up to 10-13 Ampere
- Dark noise: < 10 cpm (0.2 cpm typical)
- Stability: < 0.2 % drift per hour at 300 kcps
Data acquisition system of ARGUS-VI noble Gas Mass Spectrometer:
Argus VI noble gas mass spectrometer can be used in following three modes:
- Multi collector Mode: This allows to simultaneously acquire all Argon isotope masses from 36 to 40 from Faraday collector array wired in preamp with feedback resistors of 1012 Ohm for samples providing sufficient amount of gas for the analysis.
- Peak Switching Ion counting Mode: This mode can be programmed with Compact Discrete Dynode (CDD-Electron Multiplier) for high precision analysis on very small gas fraction from single grain specimen.
- Combination Mode: This mode can be used to measure all small amount of gases on multiplier and large amount of gas fraction on Faraday cups. Usually with single grain analysis mass 40 is measured on Faraday and masses from 36 to 39 are measured by CDD electron multiplier in peak jumping mode.
Multipurpose Sample preparation systems:
A Low blank Dual Vacuum resistance heating Furnace capable of controlled heating at variable temperatures up to 1800 C used for bulk sample analysis.
The laser heating gas extraction system equipped with a Lumics Solid state diode 80 watt laser system. The laser produces continuous 873 nm beam with output power continuously variable up to 80 W. The beam can be focused to a spot size of 600 μm capableof total fusion of single crystals and multiple grain aggregates.
A vacuum crushing system for analyzing trapped gases.
A stainless steel UHV (of the order of 1 X 10-9 mbar or lower) manifold withFour Getters pumps for gas cleanup gases connects the different gas extraction systems like single grain laser heating, Laser ablation of fluid inclusion, vacuum crushing of fluid inclusion or step heating of bulk sample or mineral to the mass spectrometer through a series of valves.
Irradiations are carried out in the DHRUVA Reactor at Bhabha Atomic Research Centre, Mumbai.
This state-of-the-art National Facility for 40Ar-39Ar geo- and thermo-chronology at IIT Bombay funded by the DST New Delh and IIT Bombay is centered on the ThermoFisherARGUS VI multicollector noble-gas mass spectrometer. A stainless steel UHV (of the order of 1 X 10-9 mbar or lower) manifold with Four Getters pumps for gas cleanup gases connects the different gas extraction systems like single grain laser heating, Laser ablation of fluid inclusion, vacuum crushing of fluid inclusion or step heating of bulk sample or mineral to the mass spectrometer through a series of valves
This dating method utilizes the accumulation of radiogenic 40Ar from 40K by decay with the half-life of 40K is 1.25 Ga. This is a modified K-Ar dating method and allows dating of a variety of samples that contain reasonable amounts of potassium, particularly K-rich minerals such as K-feldspar, micas and hornblende.
Age determinations require the measurements of K and Ar isotope abundances within a sample.Samples, rocks or minerals to be dated by the Ar-Ar method are irradiated by fast neutrons within a nuclear reactor. After irradiation, the Argon is extracted from the samples within an ultra-high vacuum (UHV) system by using either an IR laser or a furnace system. After cleaning, the isotope abundances of Ar were measured using a sector field mass spectrometer. From the measured 40Ar/39Ar ratio, the age of a sample can be calculated.
Supporting Facilities :
Sample-preparation facilities at IITB-DST National facility, Earth Sciences, IIT Bombay include a jaw crusher, disk pulverizer, Franz magnetic separator and facilities for heavy-liquid separations using sodium poly-tungstate. Additional supporting equipment such as thin section preparation is available in the Department of Earth Sciences at IIT Bombay. Excellent analytical equipment is available for sample characterization, including an automated Panalytical X-ray diffractometer, JobinYvon ICP spectrometer for the analysis of major and trace elements, and a DST-IITB National Facility for electron microscopy and EPMA.
Archisman Sen, Kanchan Pande, Ernst Hegner , Kamal Kant Sharma , A.M. Dayal, Hetu C. Sheth, Harish Mistry (2012) Deccan volcanism in Rajasthan: 40Ar–39Ar geochronology and geochemistry of the Tavidar volcanic suite Jour. Asian Earth Sci 59.127–140
Sharmistha De Sarkar, George Mathew, Kanchan Pande (2013) Arc parallel extension in Higher and Lesser Himalaya, Evidence from Western Arunachal Himalaya, India J. Earth Syst. Sci. 122, 715–727
Ray Jyotiranjan S, Pande Kanchan, Awasthi Neeraj (2013) A minimum age for the active Barren Island volcano, Andaman Sea, Current Science 104, 934-939
George Mathew, Sharmistha De Sarkar, Kanchan Pande, S Dutta, Shakir Ali, Apritam Rau, Shilpa Netravali (2013) Thermal metamorphism of the Arunachal Himalaya, India:Raman thermometry and thermochronlogical constraints on the tectonothermal evolution, Int J Earth Sci (Geol Rundsch) DOI 10.1007/s00531-013-0904-6
A. Samanta, M.K. Bera, Ruby Ghosh, Subir Bera, Timothy Filley, Kanchan Pande, S. S. Rathore, Jyotsana Rai, A. Sarkar (2013) Do the large carbon isotopic excursions in terrestrial organic matter across Palaeocene- Eocene boundary in India indicate intensification of tropical precipitation? Palaeogeog. Palaeoclimat. Palaeoecol. doi: 10.1016/j.palaeo.2013.07.008
Sharmistha De Sarkar, George Mathew, Kanchan Pande, Singhvi Ashok (2013) Rapid denudation of Higher Himalaya during Late Pleistocene, evidence from OSL Thermochronolgy, Geochronometria 40,304-310 DOI 10.2478/s13386-013-0124-7
Ray Jyotiranjan S., Pande Kanchan, Bhutani Rajneesh, Alok Kumar, Rai V.K., Shukla Anil D., Awasthi Neeraj, R.S. Smitha, Dipak K. Panda (2013) Age and geochemistry of Newania dolomite carbonatites, India: implications for the source of primary carbonatite magma Contib. Mineral. Petrol. DOI 10.1007/s00410-013-0945-7
Sheth Hetu C., Pande Kanchan (2013) Geological and 40Ar/39Ar age constraints on late-stage Deccan rhyolitic volcanism, inter-volcanic sedimentation, and the Panvel flexure from the Dongri area, Mumbai, to appear in Jour. Asian Earth Sci 84 167-175 DOI 10.1016/j.jaes.2013.08.003.
Sahu, N., Gupta, T., Patel, S.C., Khuntia, D.B.K., Behera, D., Pande, K., and Das, S.K., (2013) Petrology of lamproites from the Nuapada Lamproite Field, Bastar Craton, India Jour. Geol. Soc. India, Special Volume, 137-165 DOI: 10.1007/978-81-322-1170-9_9
Archisman Sen, Kanchan Pande, Hetu C. Sheth, Kamal Kant Sharma, A. M Dayal, Harish Mistry, Shraboni Sarkar (2013) An Ediacaran-Cambrian thermal imprint in Rajasthan, western India: Evidence from 40Ar-39Ar geochronology of the Sindreth volcanics J. Earth Syst. Sci. 122 1477-1493
Lala T, Mombasawala L. S., Pande K and Paul D. K. (2014) New 39Ar–40Ar ages of dykes from Madhya Pradesh and Chhattisgarh: evidence for polyphase dyke intrusion in eastern Deccan Volcanic Province, Current Science 107, 1027-1032
Sheth, H.C. and Pande, K. (2014) Geological and 40Ar/39Ar age constraints on late-stage Deccan rhyolitic volcanism, inter-volcanic sedimentation, and the Panvel flexure from the Dongri area, Mumbai, Jour. Asian Earth Sci 84, 165-175
Sharmistha De Sarkar, George Mathew, Kanchan Pande, Parag Pjukon, Singhvi Ashok (2014) Drainage migration and out of sequence thrusting in Bhalukpong,Western Arunachal Himalaya, Indiab, Journal of Geodynamics 81, 1–16
Awasthi, N., Ray, Jyotiranjan S. and Kanchan Pande (2015) Origin of the Mile Tilek Tuff, South Andaman: evidence from 40Ar–39Ar chronology and geochemistry, Current Science 108, 205-210
Ciro Cucciniello, Elena I. Demonterova, Hetu Sheth, Kanchan Pande and Anjali Vijayan (2015). 40Ar/39Ar geochronology and geochemistry of the Central Saurashtra mafic dyke swarm: insights into magmatic evolution, magma transport, and dyke-flow relationships in the northwestern Deccan Traps. Bull Volcanol 77:45 DOI 10.1007/s00445-015-0932-0
Jyotiranjan S. Ray, Kanchan Pande and Rajneesh Bhutani (2015). Dating the deep crust beneath an island arc: 40Ar/39Ar geochronology of Barren Island volcano, Andaman subduction zone. Bull Volcanol 77:5DOI 10.1007/s00445-015-0944-9
Paul R. Renne, Courtney J. Sprain, Mark A. Richards, Stephen Self, Loÿc Vanderkluysen, Kanchan Pande (2015) State shift in Deccan volcanism at the Cretaceous-Paleogene boundary, possibly induced by impact, Science, 350,76-78.
Santanu Banerjee, Udita Bansal, Kanchan Pande, S.S. Meena (2016) Compositional variability of glauconites within the Upper Cretaceous Karai Shale Formation, Cauvery Basin, India: Implications for evaluation of stratigraphic condensation Sedimentary Geology 331 12–29
Bansal, U., Banerjee, S., Pande, K., Arora, A., Meena, S.S. (2017). The distinctive compositional evolution of glauconite in the Cretaceous Ukra Hill Member (Kutch basin, India) and its implications. Marine and Petroleum Geology 82, 97-117
Acharyyaa, Subhrangsu K., Ghosh, Subhajit, Mandal, Nibir, Bose, Santanu, Pande, Kanchan (2017) Pre-Himalayan tectono-magmatic imprints in the Darjeeling-Sikkim Himalaya (DSH) constrained by 40Ar/39Ar dating of muscovite Jour. Asian Earth Sci 146, 211-220 DOI 10.1016/j.jaes.2017.05.027
Hetu Sheth, Kanchan Pande, Anjali Vijayan, Kamal Kant Sharma, Ciro Cucciniello (2017) Recurrent Early Cretaceous, Indo-Madagascar (89–86 Ma) and Deccan (66 Ma) alkaline magmatism in the Sarnu-Dandali complex, Rajasthan: 40Ar/39Ar age evidence and geodynamic significance, Lithos 284-285, 512-524 DOI 10.1016/j.lithos.2017.05.005
Kanchan Pande, Ciro Cucciniello, Hetu Sheth, Anjali Vijayan, Kamal Kant Sharma, Ritesh Purohit, K. C. Jagadeesan, Sapna Shinde (2017) Polychronous (Early Cretaceous to Palaeogene) emplacement of the Mundwara alkaline complex, Rajasthan, India: 40Ar/39Ar geochronology, petrochemistry and geodynamics Int J Earth Sci (Geol Rundsch) 106:1487–1504 DOI 10.1007/s00531-016-1362-8
Kanchan Pande, Vadakkeyakath Yatheesh and Hetu Sheth (2017) 40Ar/39Ar dating of the Mumbai tholeiites and Panvel flexure: intense 62.5Ma onshore–offshore Deccan magmatism during India-Laxmi Ridge–Seychelles breakup Geophys. J. Int. 210, 1160–1170 DPI: 10.1093/gji/ggx205
Shilpa Patil Pillai, Kanchan Pande and Vivek S Kale (2018) Implications of new 40Ar/39Ar age of Mallapur Intrusives on the chronology and evolution of the Kaladgi Basin, Dharwar Craton, India J. Earth Syst. Sci.127:32 doi.org/10.100.
Udita Bansal, Santanu Banerjee*, Dhiren K. Ruidas, Kanchan Pande (2018) Origin and geochemical characterization of the glauconites in the Upper Cretaceous Lameta Formation, Narmada Basin, central India Journal of Palaeogeography, 7(2): 99e116 (00141)
Elizabeth J. Catlos, Emily C. Pease, Nick Dygert1, Michael Brookfield, Winfried H. Schwarz, Rajneesh Bhutani, Kanchan Pande and Axel K. Schmitt (2018) Nature, age and emplacement of the Spongtang ophiolite, Ladakh, NW India Jour Geol. Soc. London, doi.org/10.1144/jgs2018-085.
Kunda V. Badhe, Hari S. Pandalai, Kanchan Pande (2019) 40Ar/39Ar age constraints on timing of a late hydrothermal event in the Hutti greenstone belt, Karnataka, India, Jour. Asian Earth Sciences, doi.org/10.1016/j.jseaes.2018.08.016
Udita Bansal, Kanchan Pande, Santanu Banerjee, Raghavendramurthy Nagendra, Koyyodan Cheria Jagadeesan (2019) The timing of oceanic anoxic events in the Cretaceous succession of Cauvery Basin: Constraints from 40Ar/39Ar ages of glauconite in the Karai Shale Formation Geological Journal, 54:308–315 DOI: 10.1002/gj.3177
Cucciniello C, Choudhary AK, Pande K, and Sheth H. (2019) Mineralogy, geochemistry and 40Ar–39Ar geochronology of the Barda and Alech complexes, Saurashtra, north western Deccan Traps: early silicic magmas derived by flood basalt fractionation. Geological Magazine doi.org/10.1017/S0016756818000924
Hrishikesh Samant, Vanit Patel, Kanchan Pande, Hetu Sheth, K.C. Jagadeesan (2019) 40Ar/39Ar dating of tholeiitic flows and dykes of Elephanta Island, Panvel flexure zone, western Deccan Traps: A five-million-year record of magmatism preceding India-Laxmi Ridge-Seychelles breakup. Journal of Volcanology and Geothermal Research 379,12–22. doi.org/10.1016/j.jvolgeores.2019.05.004
Vivek S. Kale, Gauri Dole, Priyanka Shandilya, and Kanchan Pande (2019) Stratigraphy and correlations in Deccan Volcanic Province, India: Quo Vadis? GSA Bulletin https doi.org/10.1130/B35018.1
B.M. Beheraa, B.D. Waeleb, V. Thirukumarand, K. Sundaralingame, S. Narayanana, B. Sivalingama, T.K. Biswal (2019) Kinematics, strain pattern and geochronology of the Salem-Attur shear zone: Tectonic implications for the multiple sheared Salem-Namakkal blocks of the Southern Granulite terrane, India,Precam. Res.,324,32-61, doi.org/10.1016/j.precamres.2019.01.022
Chatterjee, A., Ray, J.S., Shukla, A.D., Pande, K. (2019) On the existence of a perennial river in the Harappan heartland. Scientific Reports DOI: 10.1038/s41598-019-53489-4
Chakraborty, S, Mukul, M., Mathew, G., Pande, K. (2019) Major shear zone within the Greater Himalayan Sequence and sequential evolution of the metamorphic core in Sikkim, India. Tectonophysics, 770, 5. DOI: 10.1016/j.tecto.2019.228183 U Bansal, S Banerjee, K Pande, DK Ruidas (2020) Unusual seawater composition of the Late Cretaceous Tethys imprinted in glauconite of Narmada basin, central India Geological Magazine 157 (2), 233-247
VS Kale, M Bodas, P Chatterjee, K Pande (2020) Emplacement history and evolution of the Deccan Volcanic Province, India Episodes Journal of International Geoscience 43 (1), 278-299
P Shandilya, P Chatterjee, K Pattabhiram, M Bodas, K Pande, VS Kale (2020) Rajgad GPB: A megaporphyritic flow field, Western Deccan Volcanic Province, India Journal of Earth System Science 129, 1-11
D Salvi, G Mathew, B Kohn, K Pande, B Borgohain (2020) Thermochronological insights into the thermotectonic evolution of Mishmi hills across the Dibang Valley, NE Himalayan Syntaxis Journal of Asian Earth Sciences 190, 104158
S Bhattacharya, K Pande, A Kumar, O Kingson, JS Ray (2020) Timing of Formation and Obduction of the Andaman Ophiolite J. S. Ray and M. Radhakrishna (eds.), The Andaman Islands and Adjoining Offshore: Geology, Tectonics and Palaeoclimate, Society of Earth Scientists Series,https://doi.org/10.1007/978-3-030-39843-9_2
VS Kale, G Dole, P Shandilya, K Pande (2020) Stratigraphy and correlations in Deccan Volcanic Province, India: Quo vadis? Geological Society of America Bulletin 132 (5-6), 1344-1344
Mathew, G, De Sarkar, S. and Pande, K. (2012). Foreland out-of Sequence thrusting and rapid Pleistocene exhumation of Higher Himalayan crustal rocks in the Western Arunachal Himalaya. Geophysical Research Abstracts Vol. 14, EGU2012-10559.
Sharmistha De Sarkar, Naveen Chauhan, George Mathew, K. Pande and A. K. Singhvi (2013). Late Pleistocene rapid denudation, million to thousand-year scale. 3rdAsia Pacific conference on Luminescence and ESR dating (APLED-3), Advances in ESR Applications, 29, 2012.
Salvi, D, Mathew, Pande, K and Kohn, B (2014). Thermochronological investigation of Higher and Lesser Himalayan Crystallines of West Siang, NE India: constraints from patite fission track dating and three-dimensional modeling. Thermo 2014, France.
Kanchan Pande, Jyotiranjan S. Ray and Rajneesh Bhutani (2014) Dating of the deep crust beneath an island arc: 40Ar/39Ar geochronology of the Barren Island volcano, Andaman Sea. GSA 2014, Vancouver.
Salvi, D, Mathew, G, Kohn, B, P., and Pande, K (2015). Thermochronological constraints from the Siyom Valley and growth of Namche Barwa Antiform, Eastern Himalaya 30th HKT,Dehradun.
Pande Kanchan and Ray Jyotiranjan S. (2015) 40Ar/39Ar geochronology of Andaman Ophiolite: Evidence for a Pleistocene mega thrusting event within the Andaman-Nicobar Accretionary Wedge, AGU Fall Meeting San Francisco.
P Renne, C Sprain, K Pande, M Richards, L Vanderkluysen, S Self (2016) Tempo of the Deccan Traps eruptions in relation to events at the Cretaceous-Paleogene boundary, EGU General Assembly Conference 18, 9496
Vijayan, A., Pande K., Sheth H. C.and Sharma K. K. (2016). 40Ar/39Ar dating of the Sarnu-Dandali complex (Rajasthan, northwestern India): Intracontinental alkaline magmatism related to India-Madagascar break-up (~86 Ma) as well as Deccan volcanism (~66 Ma). Geological Society of india Annual Conference 2016, IIt Kharagpur India.
Vijayan, A., Pande K., Sheth H. C.and Sharma K. K. (2017). 40Ar/39Ar age recored and geodynamic significance of Indo-Madagascar and Deccan flood basalt volcanism in the Sarnu-Dandali complex (Rajasthan, northwestern India. European geosciences Union General Assembly Vienna, Austria.
For most Ar-Ar work fresh 500 g specimen is sufficient for whole rock analysis.For mineral separation, depending on the concentration of the mineral of interest, the samples size may vary (few kilo gram).
Users can submit either whole rock samples or separated mineral depending on their requirement and available facilities with them
Final Preparation and Irradiation of samples is carried out in our laboratory
Packaging Your Samples for Shipment to 40Ar/39Ar Geochronology Laboratory, IIT Bombay: For purified mineral separates, please ensure that your vials are tightly sealed. Send samples to the contact addressed listed on the lab's home page. For whole rock kindly ensure they are clearly labeled.
Amount of Sample. For total-fusion analyses, we generally analyze about 0.2 gand about 30 mg mineral separate, so that we can run multiple aliquots.
Generally, we expect all users to carry out their own mineral separations. We can advise on sample quality and purity. We carry out the final sample preparation and loading for irradiation. The costs for analyses does not include the cost of mineral-separatiion. Quoted cost includes the materials and supplies involved in final sample preparation, loading for irradiation, the irradiation, analysis and data reduction.
Sample and Charges:
Type of Sample University charges Industrial Charges
Whole Rock 30000 60000
Mineral Separates 30000 60000
Single mineral grain 30000 60000
Final sample preparation and irradiation will be taken care. For more clarification please contact the convener of the facility.
The DD along with sample and covering letter should be sent to:
The Convener, Argon-Argon Geochronology facility
Department of Earth Sciences
Indian Institute of Technology, Bombay
Powai - 400076