Moho depth variation in Archean cratons using Receiver function modelling

Roy, Abhishek (2022) Moho depth variation in Archean cratons using Receiver function modelling. Masters thesis, Indian Institute of Science Education and Research Kolkata.

Text (MS dissertation of Abhishek Roy (17MS149)) 17MS149_Thesis_file.pdf - Submitted Version Restricted to Repository staff only Download (7MB)

Abstract

Investigating the lithospheric character of Precambrian cratons is essential to understand their formation and evolution. In this study, we are numerically modelling and imaging the lithosphere to understand the differences in the nature of the crust and upper mantle of the Archean cratons. We have investigated the Zimbabwe and Kaapvaal craton of South Africa and Slave and Superior craton of North America and Antarctica. The data consists of teleseismic earthquakes with epicentral distances lying between 30⁰ and 95⁰ and having magnitude more than 5.5. The crustal properties obtained have been used to interpret the nature of crust and age relationship between different craton and the Moho depth. It was found in our study that the crustal thickness in Zimbabwe and Kaapvaal have varies from 35 to 38 km and 33 to 37 km respectively. The range of variation of the Vp/Vs ratio for both the craton was almost similar. For the cratons situated in North America, i.e. Slave craton it was found that the range of variation of Vp/Vs ratio in is almost similar. The variation in crustal range from 35 to 40 km in Superior Provinces and for slave it was in range from 33 to 39 km in the southern part of the craton. From the northern part of the craton, we analyzed only one station, which gives us the crustal thickness as 41 km beneath the station. For Antarctica, we analyzed only two stations. The Moho depth beneath the stations are 35.9 and 39.3 respectivly When we compare the Moho and Vp/Vs for all the station that we have used in our study we get a positive correlation between Moho and Vp/Vs. For insufficient data, we were not able to comment on the age and crustal thickness using our study.

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