Application of 55 multi-dimensional tectonomagmatic discrimination diagrams to Precambrian belts

Author(s)

Verma, Surendra P. ; Verma, Sanjeet K. ; Oliveira, Elson P.

• Document type: Journal article
• Source: INTERNATIONAL GEOLOGY REVIEW; v. 57, n. 11-12, p. 24-pg., 2015-09-10.

Abstract

Fifty-five new multi-dimensional diagrams, mostly based on log-ratio transformations, were used to decipher tectonic settings for 17 cases of Precambrian belts in Canada, the USA, Poland, Finland, Jordan, Democratic Republic of CongoandZambia, China, and India. The results of different sets of diagrams for basic-ultrabasic, intermediate, and acid magmas were generally internally consistent. Possible reasons for some inconsistencies may be related to the use of a sample group of mixed ages because of their uncertainties, extreme element mobility caused by metamorphism especially of high-grade type, analytical data quality, different petrogenetic processes for basic to acid magmas such as mantle versus crustal origin, and some deficiencies that still exist in the multi-dimensional diagrams. To partly overcome the last problem, one new multi-dimensional diagram is proposed and used to discriminate mid-ocean ridge and oceanic plateau settings. (AU)

• FAPESP's process: 12/07243-3 - Application of new multi-dimensional discrimination diagrams and geochemical modeling to Archaean igneous rocks of Brazilian cratons
• Grantee: Sanjeet Kumar Verma
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 12/15824-6 - Evolution of archaean terranes of the São Francisco Craton and the Borborema Province, Brazil: global environmental and geodynamic implications
• Grantee: Elson Paiva de Oliveira
• Support Opportunities: Research Projects - Thematic Grants