New U-Pb-Hf zircon isotope data for the Paleoproterozoic Ubendian belt in the Chimala area, SW Tanzania
We present new U-Pb and Hf zircon isotope data on a suite of granitoids from a hitherto unstudied area of the Palaeoproterozoic Lupa terrane of the Ubendian belt in SW Tanzania. The major part of the area comprises a sequence of upper amphibolite grade paragneisses and migmatites. Subsequently, the...
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2019-11-01
|
| Series: | Geoscience Frontiers |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1674987118301361 |
| _version_ | 1797706161595613184 |
|---|---|
| author | Robert J. Thomas Joachim Jacobs Marlina A. Elburg Abdul Mruma Godson Kamihanda Anthony Kankila Alex Masanja Hamisi Saidi |
| author_facet | Robert J. Thomas Joachim Jacobs Marlina A. Elburg Abdul Mruma Godson Kamihanda Anthony Kankila Alex Masanja Hamisi Saidi |
| author_sort | Robert J. Thomas |
| collection | DOAJ |
| description | We present new U-Pb and Hf zircon isotope data on a suite of granitoids from a hitherto unstudied area of the Palaeoproterozoic Lupa terrane of the Ubendian belt in SW Tanzania. The major part of the area comprises a sequence of upper amphibolite grade paragneisses and migmatites. Subsequently, the field relations show a complex history of granitoid emplacement from early pre-tectonic strongly foliated diorite-tonalite-granodiorite orthogneiss to late tectonic, weakly deformed ellipsoidal granitoid plutons. These were followed by emplacement of undeformed K-feldspar rich porphyritic alkali granite. U-Pb zircon data on the granitoids show their emplacement ages span the period ∼1925 Ma to 1890 Ma and constrain the culmination of the Ubendian orogeny in the Lupa terrane to about 1900 Ma. The undeformed K-feldspar rich Chimala granite, previously considered to be unconformably overlain by the Buanji Group volcano-sedimentary rocks (recently shown to be ∼1675 Ma, not Neoproterozoic as originally thought) was dated at ∼1407 Ma showing that it must intrude the sedimentary rocks, although the age relationships are not exposed in the mapping area. This is the first record of early Irumide/Kibaran-aged post-tectonic granites in this part of East Africa. Hf isotope data from the zircons show that the granitoids have a long crustal pre-history stretching back to as far as ∼3.9 Ga, and showing that the Lupa terrane may form part of the “metacratonic” margin of an originally much more extensive Tanzania Craton. Keywords: Geochronology, Tanzania, Ubendian, Palaeoproterozoic, Mesoproterozoic |
| first_indexed | 2024-03-12T05:48:11Z |
| format | Article |
| id | doaj.art-120c1b74080544e993781f5f11b978d8 |
| institution | Directory Open Access Journal |
| issn | 1674-9871 |
| language | English |
| last_indexed | 2024-03-12T05:48:11Z |
| publishDate | 2019-11-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Geoscience Frontiers |
| spelling | doaj.art-120c1b74080544e993781f5f11b978d82023-09-03T05:25:45ZengElsevierGeoscience Frontiers1674-98712019-11-0110619932006New U-Pb-Hf zircon isotope data for the Paleoproterozoic Ubendian belt in the Chimala area, SW TanzaniaRobert J. Thomas0Joachim Jacobs1Marlina A. Elburg2Abdul Mruma3Godson Kamihanda4Anthony Kankila5Alex Masanja6Hamisi Saidi7Council for Geoscience, 3 Oos Street, Bellville, Cape Town, 7535, South Africa; Corresponding author.Department of Earth Science, University of Bergen, PO Box 7803, NorwayDepartment of Geology, University of Johannesburg, PO Box 524, Auckland Park, 2006, South AfricaGeological Survey of Tanzania, Dodoma, TanzaniaGeological Survey of Tanzania, Dodoma, TanzaniaGeological Survey of Tanzania, Dodoma, TanzaniaGeological Survey of Tanzania, Dodoma, TanzaniaGeological Survey of Tanzania, Dodoma, TanzaniaWe present new U-Pb and Hf zircon isotope data on a suite of granitoids from a hitherto unstudied area of the Palaeoproterozoic Lupa terrane of the Ubendian belt in SW Tanzania. The major part of the area comprises a sequence of upper amphibolite grade paragneisses and migmatites. Subsequently, the field relations show a complex history of granitoid emplacement from early pre-tectonic strongly foliated diorite-tonalite-granodiorite orthogneiss to late tectonic, weakly deformed ellipsoidal granitoid plutons. These were followed by emplacement of undeformed K-feldspar rich porphyritic alkali granite. U-Pb zircon data on the granitoids show their emplacement ages span the period ∼1925 Ma to 1890 Ma and constrain the culmination of the Ubendian orogeny in the Lupa terrane to about 1900 Ma. The undeformed K-feldspar rich Chimala granite, previously considered to be unconformably overlain by the Buanji Group volcano-sedimentary rocks (recently shown to be ∼1675 Ma, not Neoproterozoic as originally thought) was dated at ∼1407 Ma showing that it must intrude the sedimentary rocks, although the age relationships are not exposed in the mapping area. This is the first record of early Irumide/Kibaran-aged post-tectonic granites in this part of East Africa. Hf isotope data from the zircons show that the granitoids have a long crustal pre-history stretching back to as far as ∼3.9 Ga, and showing that the Lupa terrane may form part of the “metacratonic” margin of an originally much more extensive Tanzania Craton. Keywords: Geochronology, Tanzania, Ubendian, Palaeoproterozoic, Mesoproterozoichttp://www.sciencedirect.com/science/article/pii/S1674987118301361 |
| spellingShingle | Robert J. Thomas Joachim Jacobs Marlina A. Elburg Abdul Mruma Godson Kamihanda Anthony Kankila Alex Masanja Hamisi Saidi New U-Pb-Hf zircon isotope data for the Paleoproterozoic Ubendian belt in the Chimala area, SW Tanzania Geoscience Frontiers |
| title | New U-Pb-Hf zircon isotope data for the Paleoproterozoic Ubendian belt in the Chimala area, SW Tanzania |
| title_full | New U-Pb-Hf zircon isotope data for the Paleoproterozoic Ubendian belt in the Chimala area, SW Tanzania |
| title_fullStr | New U-Pb-Hf zircon isotope data for the Paleoproterozoic Ubendian belt in the Chimala area, SW Tanzania |
| title_full_unstemmed | New U-Pb-Hf zircon isotope data for the Paleoproterozoic Ubendian belt in the Chimala area, SW Tanzania |
| title_short | New U-Pb-Hf zircon isotope data for the Paleoproterozoic Ubendian belt in the Chimala area, SW Tanzania |
| title_sort | new u pb hf zircon isotope data for the paleoproterozoic ubendian belt in the chimala area sw tanzania |
| url | http://www.sciencedirect.com/science/article/pii/S1674987118301361 |
| work_keys_str_mv | AT robertjthomas newupbhfzirconisotopedataforthepaleoproterozoicubendianbeltinthechimalaareaswtanzania AT joachimjacobs newupbhfzirconisotopedataforthepaleoproterozoicubendianbeltinthechimalaareaswtanzania AT marlinaaelburg newupbhfzirconisotopedataforthepaleoproterozoicubendianbeltinthechimalaareaswtanzania AT abdulmruma newupbhfzirconisotopedataforthepaleoproterozoicubendianbeltinthechimalaareaswtanzania AT godsonkamihanda newupbhfzirconisotopedataforthepaleoproterozoicubendianbeltinthechimalaareaswtanzania AT anthonykankila newupbhfzirconisotopedataforthepaleoproterozoicubendianbeltinthechimalaareaswtanzania AT alexmasanja newupbhfzirconisotopedataforthepaleoproterozoicubendianbeltinthechimalaareaswtanzania AT hamisisaidi newupbhfzirconisotopedataforthepaleoproterozoicubendianbeltinthechimalaareaswtanzania |