Central Tanzanian tectonic map: A step forward to decipher Proterozoic structural events in the East African Orogen

Fritz, Harald; Tenczer, V.; Hauzenberger, Christoph; Wallbrecher, E.; Hoinkes, G.; Muhongo, S.; Mogessie, Aberra

doi:10.1029/2005tc001796

Cited by 60 publications

(57 citation statements)

References 38 publications

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“…9). They are also consistent with reported igneous and metamorphic ages from the southern klippen (Krö ner et al 1997;Grantham et al 2008), suggesting that they are remnants of the same granulite-facies nappe complex that may have continued northward into the Eastern Granulites in Tanzania (e.g., Coolen et al 1982;Fritz et al 2005) and southward (within a reconstructed Gondwana) into the Schirmacher Oasis in East Antarctica (Baba et al 2010). A group of younger (!490 Ma) U-Pb and 40 Ar/ 39 Ar ages in the CDNC is not well understood and may indicate limited reactivation of collisional structures, for example, during extension.…”

Section: Regional Implications and Discussionsupporting

confidence: 85%

Postcollisional High-Grade Metamorphism, Orogenic Collapse, and Differential Cooling of the East African Orogen of Northeast Mozambique

Ueda

Jacobs²,

Thomas³

et al. 2012

The Journal of Geology

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A B S T R A C TThe postcollisional tectonic development of northeast Mozambique and subsequent cooling from high-temperature metamorphism is delineated with an extensive new set of U-Pb titanite, 40 Ar/ 39 Ar hornblende, and 40 Ar/ 39 Ar mica analyses. The complex data suggest a polyphase metamorphic history from the late Neoproterozoic to the Ordovician within the East African-Antarctic Orogen (EAAO), with marked differences between the major constituent blocks. In all the data sets, samples from the basement south of the Lú rio Belt show generally younger ages than those from the north, resulting from a late metamorphic event and slow cooling between ca. 520 and 440 Ma. The ages north and south of the Lú rio Belt are consistently offset by ca. 30-70 Ma, a difference that is maintained and even appears to increase during cooling from very high temperatures to ca. 350ЊC. Based on the first-order assumption that all the ages are cooling ages, cooling rates in the south are estimated at ca. 7Њ-8ЊC/Ma, while those north of the Lú rio Belt are faster at ca. 16ЊC/Ma. The data are consistent with previous geochronological, petrographic, and field data and suggest a late high-temperature/low-pressure metamorphic event that affected only the basement rocks south of the Lú rio Belt and portions of the latter. This late metamorphism and subsequent delayed, slower cooling agree well with a model of elevated heat flow following lithosphere delamination in the southern part of the orogen, which also explains the observed widespread granitoid magmatism, migmatization, and renewed deformation in the southern basement.

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Section: Regional Implications and Discussionsupporting

confidence: 85%

Postcollisional High-Grade Metamorphism, Orogenic Collapse, and Differential Cooling of the East African Orogen of Northeast Mozambique

Ueda

Jacobs²,

Thomas³

et al. 2012

The Journal of Geology

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“…The eastern parts of the Usagaran Belt were reworked during the Neoproterozoic East African Orogeny and have been designated the Western Granulites, while further to the east, a unit of younger Mesoproterozoic rocks composed of enderbitic gneisses (metamorphosed igneous rocks of the charnockite series), schists, and marbles has been named the Eastern Granulites (Fritz et al, 2005). The Eastern and Western Granulites were metamorphosed simultaneously, and together they constitute the Neoproterozoic Mozambique Belt of Tanzania and Kenya.…”

Section: Geologic Settingmentioning

confidence: 99%

“…Structurally, the Usagaran Belt constitutes the eastern border of the Archean Tanzania Craton (see, e.g., Fritz et al, 2005).…”

Section: Geologic Settingmentioning

confidence: 99%

Rubies and Sapphires from Winza, Central Tanzania

Schwarz¹,

Pardieu²,

Saul³

et al. 2008

Gems & Gemology

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“…These rocks, known broadly as the "Western Granulites" (e.g. Fritz et al, 2005) were first shown to have Neoarchaean protolith ages by Maboko (2000). Direct U-Pb zircon dating at ca.…”

Section: Precambrian Geology Of the Studied Areasmentioning

confidence: 99%

Geochronology of the central Tanzania Craton and its southern and eastern orogenic margins

Thomas

Spencer

Bushi³

et al. 2016

Precambrian Research

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Geological mapping and zircon U-Pb/Hf isotope data from 35 samples from the central Tanzania Craton and surrounding orogenic belts to the south and east allow a revised model of Precambrian crustal evolution of this part of East Africa. The geochronology of two studied segments of the craton shows them to be essentially the same, suggesting that they form a contiguous crustal section dominated by granitoid plutons. The oldest orthogneisses are dated at ca. 2820 Ma (Dodoma Suite) and the youngest alkaline syenite plutons at ca. 2610 Ma (Singida Suite). Plutonism was interrupted by a period of deposition of volcano-sedimentary rocks metamorphosed to greenschist facies, directly dated by a pyroclastic metavolcanic rock which gave an age of ca. 2725 Ma. This is supported by detrital zircons from psammitic metasedimentary rocks, which indicate a maximum depositional age of ca. 2740 Ma, with additional detrital sources 2820 and 2940 Ma. Thus, 200 Ma of episodic magmatism in this part of the Tanzania Craton was punctuated by a period of uplift, exhumation, erosion and clastic sedimentation/volcanism, followed by burial and renewed granitic to syenitic magmatism.In eastern Tanzania (Handeni block), in the heart of the East African Orogen, all the dated orthogneisses and charnockites (apart from those of the overthrust Neoproterozoic granulite nappes), have Neoarchaean protolith ages within a narrow range between 2710 and 2630 Ma, identical to (but more restricted than) the ages of the Singida Suite. They show evidence of Ediacaran "Pan-African" isotopic disturbance, but this is poorly defined. In contrast, granulite samples from the Wami Complex nappe were dated at ca. 605 and ca. 675 Ma, coeval with previous dates of the "Eastern Granulites" of eastern Tanzania and granulite nappes of adjacent NE Mozambique. To the south of the Tanzania Craton, samples of orthogneiss from the northern part of the Lupa area were dated at ca. 2730 Ma and clearly belong to the Tanzania Craton. However, granitoid samples from the southern part of the Lupa "block" have Palaeoproterozoic (Ubendian) intrusive ages of ca. 1920 Ma. Outcrops further south, at the northern tip of Lake Malawi, mark the SE continuation of the Ubendian belt, albeit with slightly younger ages of igneous rocks (ca. 1870-1900 Ma) which provide a link with the Ponte Messuli Complex, along strike to the SE in northern Mozambique.In SW Tanzania, rocks from the Mgazini area gave Ubendian protolith ages of ca. 1980-1800 Ma, but these rocks underwent Late Mesoproterozoic high-grade metamorphism between 1015 and 1040 Ma. One granitoid gave a crystallisation age of ca. 1080 Ma correlating with known Mesoproterozoic crust to the east in SE Tanzania and NE Mozambique. However, while the crust in the Mgazini area was clearly one of original Ubendian age, reworked and intruded by granitoids at ca. 1 Ga, the crust of SE Tanzania is a mixed Mesoproterozoic terrane and a continuation from NE Mozambique. Hence the Mgazini area lies at the edge of the Ubendian belt which was re...

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Central Tanzanian tectonic map: A step forward to decipher Proterozoic structural events in the East African Orogen

Cited by 60 publications

References 38 publications

Postcollisional High-Grade Metamorphism, Orogenic Collapse, and Differential Cooling of the East African Orogen of Northeast Mozambique

Postcollisional High-Grade Metamorphism, Orogenic Collapse, and Differential Cooling of the East African Orogen of Northeast Mozambique

Rubies and Sapphires from Winza, Central Tanzania

Geochronology of the central Tanzania Craton and its southern and eastern orogenic margins

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