Thermo-tectonic evolution of the North Singhbhum Mobile Belt (eastern India): A view from the western part of the belt

∼1.6 Ga ultrahigh‐temperature granulite metamorphism in the Central Indian Tectonic Zone: insights from metamorphic reaction history, geothermobarometry and monazite chemical ages

“…The NSMB is delimited from the Archaean Singhbhum Craton (part of the SIB) in the south and the CGC in the north by two prominent north-dipping ductile shear zones, the Singhbhum Shear Zone (SSZ) and the South Purulia Shear Zone (SPSZ), respectively. The NSMB is composed of a thick, multiple deformed, metasedimentary sequence of pelites, psammites and volcaniclastics (depositional age <2.4 Ga; Mahato et al, 2008), and mafic-ultramafic rocks (Dalma Metaigneous Suite) and felsic volcanic rocks. The Dalma Metaigneous suite, represented by deformed and metamorphosed hornblende schists, chlorite schists and talc schists (cf.…”

“…Intermediate pressure greenschist facies metamorphic conditions (P$4.4-5.3 kbar, T$450-5808C, Sini area, Lal et al, 1987;P$6.4 kbar, T$4808C, Surda, Sengupta et al, 2005; P$5.5 kbar, T$5508C, Dhalbhumgarh, Ghosh et al, 2006) are uniformly recorded all along the southern part of the belt, whereas high-P amphibolite facies (P$10 kbar; T$6258C) metamorphism has been established from the central sector . For both these sectors, a clockwise metamorphic P-T path has been proposed (Ghosh et al, 2006;Mahato et al, 2008). Mahato et al (2008) recently assigned an Early Mesoproterozoic age ($1.5 Ga) for this high-P metamorphism, based on detailed EMP dating of monazites.…”

“…For both these sectors, a clockwise metamorphic P-T path has been proposed (Ghosh et al, 2006;Mahato et al, 2008). Mahato et al (2008) recently assigned an Early Mesoproterozoic age ($1.5 Ga) for this high-P metamorphism, based on detailed EMP dating of monazites. An Early Mesoproterozoic age was also recorded from the bounding SSZ at the southern margin of the NSMB, based on U-Pb uraninite dating (Rao et al, 1979).…”

“…These granulites were subsequently intruded by the Bengal anorthosites (Maji et al, 2008), for which an emplacement age of $1.55 Ga was determined, based on U-Pb zircon dating, applying isotope dilution thermal ionization mass spectrometry (ID-TIMS) technique (Chatterjee et al, 2008). The date provides a minimum age for the granulite metamorphism in the CGC (Chatterjee et al, 2008;Mahato et al, 2008). A pervasive Early Mesoproterozoic thermal event in the CGC was previously inferred from whole rock Rb-Sr systematics (see Acharyya, 2003).…”

“…Contrary to earlier predictions, Archaean ages are yet to be documented in the CGC. Various tectonic models have been proposed over the years to interpret the crustal evolution in the NSMB and the CGC (summarized in Mahato et al, 2008). The majority of these models envisage an early N-S extension, leading to the opening of a volcano-sedimentary basin (cf.…”