Archaean crustal growth through successive partial melting events in an oceanic plateau-like setting in the Tanzania Craton
Journal Publication ResearchOnline@JCUAbstract
The detrital zircon population in quartzitic conglomerates from the northern Tanzania Craton yield ages between 2640 Ma and 2790 Ma which includes most of the igneous history from this part of the craton. The igneous evolution is characterised by mafic volcanism with an oceanic plateau-like geochemical signature at ~2800 Ma followed by diorite and tonalite–trondhjemite–granodiorite dominated magmatism between 2790 and 2700 Ma, which transitioned into more evolved high-K magmatism between 2700 and 2620 Ma. The εHf values of the detrital zircons range from +2.4 to -1.4 and change with time from radiogenic Hf pre-2700 Ma (98% positive εHf) to unradiogenic Hf post-2700 Ma (41% positive εHf). The petrological progression from mafic to felsic crust is reflected in the detrital age distribution and εHf isotopes and is consistent with juvenile mafic crust slowly maturing into more evolved felsic crust through a series of successive partial melting events in an oceanic-plateau-like environment.
Journal
Terra Nova
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Volume
30
ISBN/ISSN
1365-3121
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Issue
3
Pages Count
10
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Publisher
Wiley-Blackwell
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DOI
10.1111/ter.12323