Geochemical discrimination and petrogenetic affinities of dykes intruding the Ladakh batholith, NW India

Heri, A. R.; Bahl, J.; Villa, Igor M. (2019). Geochemical discrimination and petrogenetic affinities of dykes intruding the Ladakh batholith, NW India. Geological Society Special Publications, 481(1), pp. 231-250. London: Geological Society, London 10.1144/SP481-2017-150

[img]
Preview
Text
Heri-GSLSpecPub17-150_R3.pdf - Accepted Version
Available under License Publisher holds Copyright.

Download (9MB) | Preview
[img] Text
231.full.pdf - Published Version
Restricted to registered users only
Available under License Publisher holds Copyright.
Author holds Copyright

Download (2MB) | Request a copy

Eocene dykes extending over 50 km along the southern margin of the Ladakh batholith (NW India) fall into two main groups showing different orientation as well as isotope and trace element geochemistry. Both dyke families formed in the same tectonic setting over a time span of approximately 4 Ma. However, each family is far from monolithic, and therefore we tested several statistical approaches to identify geochemical subgroups from REE data and relate them to magmatogenetic processes. Hierarchical Clustering and Multidimensional Scaling calculate similarities/dissimilarities among individuals of a population. Both statistical tools, when applied to the Ladakh dykes, reflect the east-west dichotomy. However, detailed quantification of the resulting grouping varies according to input data. Normalization to chondrites yields slightly different groupings from unnormalized concentration data. Population-internal REE normalization provides the most accurate grouping as revealed by the fact that multiple samples from the same dyke are assigned the closest relatedness. Independently from normalization, east-west dichotomy is mirrored by marked differences in degree of crustal assimilation and magma evolution, pointing to km-scale geological heterogeneity. Finally, dykes intruding the Ladakh batholith 150 km SE of the present samples are geochemically similar, but cluster as distinct group.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Other Institutions > Emeriti, Faculty of Science
08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

Villa, Igor Maria

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

0305-8719

Series:

Geological Society Special Publications

Publisher:

Geological Society, London

Funders:

[UNSPECIFIED] The University of Hong Kong, Small Project Funding

Projects:

[UNSPECIFIED] Grant 200707176193

Language:

English

Submitter:

Igor Maria Villa-Toscani

Date Deposited:

15 Jan 2020 15:18

Last Modified:

19 Jun 2020 02:30

Publisher DOI:

10.1144/SP481-2017-150

Additional Information:

Title of vol. 481: Crustal Architecture and Evolution of the Himalaya-Karakoram-Tibet Orogen. - ISBN 978-1-78620-403-5

Uncontrolled Keywords:

Geochemical Discrimination; Relatedness of Magmas; Ladakh batholith dykes; Hierarchical Clustering; Multidimensional Scaling

BORIS DOI:

10.7892/boris.137804

URI:

https://boris.unibe.ch/id/eprint/137804

Actions (login required)

Edit item Edit item
Provide Feedback