Geomagnetic Field Variations in the Past: New Data, Applications and Recent Advances
In the last decades, palaeomagnetic research has provided important information about the past variation of the Earth's magnetic field (EMF) from its origin to the present day. However, questions regarding the origin and evolution of the EMF as well as the frequency and spatial distribution of its variations still remain open to debate. This Special Publication provides new insights into the study of the temporal and spatial evolution of the EMF presenting new data from palaeomagnetic and rock magnetic studies of archaeological materials, sediments and lavas. The papers presented cover a wide range of topics related to archaeology, stratigraphy and climate, including new data from several parts of the world, such as Europe, Africa, Australia, New Zealand, India and the Baltic Sea. This Special Publication aims to present an overview of the most recent secular variation studies and their use to disclose fundamental properties of the EMF evolution.
A test of the pseudo-Thellier technique for determining relative palaeointensity in the Tirna Basin, Osmanabad, Maharashtra, India
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Published:September 23, 2020
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CiteCitation
B. V. Lakshmi, K. Deenadayalan, P. B. Gawali, 2020. "A test of the pseudo-Thellier technique for determining relative palaeointensity in the Tirna Basin, Osmanabad, Maharashtra, India", Geomagnetic Field Variations in the Past: New Data, Applications and Recent Advances, E. Tema, A. Di Chiara, E. Herrero-Bervera
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Abstract
A relative palaeointensity determination was obtained using the pseudo-Thellier technique on sediment from Ther, Tirna Basin, Latu-Osmanabad District, Maharashtra, India. The stability of the natural remanent magnetization was investigated by alternating field (AF) demagnetization. Rock magnetic studies suggest that the main carriers of magnetization are ferrimagnetic minerals, predominantly pseudo-single-domain magnetite. To varying degrees, the smoothed palaeoinclination and palaeodeclination patterns of the Tirna Basin are similar to other Asian palaeosecular variation records CALS3k.4, CALS10k.1 and SED3k.1, with an age offset. Measurements of intensity of the natural remanent magnetization left after AF demagnetization v. intensity of anhysteric remanent magnetization gained at the same peak were carried out on a set of samples. A jackknife re-sampling scheme provides error estimates for the palaeointensity. A good agreement pattern can be observed between the Tirna Basin relative palaeointensity proxy and other global curves with an age shift. Although some temporal offsets of palaeointensity features between different records have been recognized, their similar shape suggests that the palaeointensity can give a globally coherent signal and may be used as a relative dating technique. For the first time, relative palaeointensity data for the past 2 kyr from India is presented here, which complement the existing archaeological records but with an additional input.
- age
- Anthropocene
- archaeology
- Asia
- C-14
- carbon
- Deccan Plateau
- demagnetization
- India
- Indian Peninsula
- isotopes
- Latur India
- magnetic intensity
- magnetic minerals
- magnetic properties
- magnetization
- Maharashtra India
- natural remanent magnetization
- paleomagnetism
- radioactive isotopes
- remanent magnetization
- secular variations
- techniques
- testing
- Thellier method
- Osmanabad India
- Tirna Basin