Maboko, M. A. H. & Eizo Nakamura (1996) Nd and Sr isotope mapping of the Archean-Proterozoic boundary in southeastern Tanzania using granites as probes for crustal growth, Precambrian Research, 77, 105-115, doi: 10.1016/0301-9268(95)00048-8. < 20150915165343-469726 > pub

Map on Earth or stone. Places and analyses are shown.

  • abstract:

    Granitoids of two different generations occur across the Archaean-Proterozoic boundary in southeastern Tanzania. The first generation, which is confined to the Archaean Tanzania Craton, yields RbSr whole-rock isochron ages of 2600 Ma and low, mantle-like, initial 87Sr/ 86Sr ratios (0.702–0.704). These coupled with positive or near-zero ε Nd values (−0.2 to 2.0) suggest that these granitoids represent juvenile mantle material which was added to the continental crust at about 2600 Ma. The second generation of granitoids intrudes the Palaeoproterozoic Usagaran Belt and is characterised by RbSr whole-rock isochron ages of about 1900 Ma. These granitoids show SmNd crustal formation ages which are 200 to 600 Ma older than their emplacement ages and negative ε Nd values (−2.2 to −6.2). Mixing calculations suggest that the Proterozoic granitoids may have formed by partial melting of 2000 Ma (Usagaran) mantle-derived material which had incorporated between 15 and 45% of an Archaean component from the adjacent Tanzania Craton.

  • doi: 10.1016/0301-9268(95)00048-8
  • modified at 15 h ago
Tixhr 733390269 thumb IRA1 < 20181001112648-007906 >pub
  • IGSN: IEDRM00RT
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 1.55
  • age (Ma): 2184 (0)
  • description: Iringa area, Proterozoic biotite granites; for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
Tixhr707603011 thumb IRA3 < 20181001112759-232844 >pub
  • IGSN: IEDRM00RU
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 0.64
  • age (Ma): 2200 (0)
  • description: Iringa area, Hula granite; for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
Tixhr 552150390 thumb IRA6 < 20181001112929-085892 >pub
  • IGSN: IEDRM00RV
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 1.44
  • age (Ma): 2319 (0)
  • description: Iringa area, Hula granite; for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
Tixhr1916317069 thumb IRA11 < 20181001113112-408531 >pub
  • IGSN: IEDRM00RW
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 1.71
  • age (Ma): 2673 (0)
  • description: Iringa area, Archaean granites; for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
Tixhr 691143999 thumb IRA17 < 20181001113341-197007 >pub
  • IGSN: IEDRM00RX
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 1.545
  • age (Ma): 2615 (0)
  • description: Iringa area, Archaean granite; for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
Tixhr1230682643 thumb IRA2 < 20181010102138-322054 >pub
  • IGSN: IEDRM00RY
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 0.71
  • age (Ma): 2317 (0)
  • description: Iringa area, Proterozoic biotite granites; for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
Tixhr2100525819 thumb IRA8 < 20181010102258-937563 >pub
  • IGSN: IEDRM00RZ
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 1.025
  • age (Ma): 2197 (0)
  • description: Iringa area, Proterozoic biotite granites; for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
Tixhr 1471388735 thumb IRA10 < 20181010102447-441422 >pub
  • IGSN: IEDRM00S0
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 1.75
  • age (Ma): 2432 (0)
  • description: Iringa area, Proterozoic biotite granites; for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
Tixhr 1834881707 thumb IRA21 < 20181010103246-230426 >pub
  • IGSN: IEDRM00S1
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 1.875
  • age (Ma): 2472 (0)
  • description: Iringa area, Proterozoic biotite granites; for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
Tixhr 1172588690 thumb IRA12 < 20181010102639-287054 >pub
  • IGSN: IEDRM00S2
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 1.575
  • age (Ma): 2613 (0)
  • description: Iringa area,Archaean biotite granites; for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
Tixhr 2115277031 thumb IRA14 < 20181010102828-819124 >pub
  • IGSN: IEDRM00S3
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 1.185
  • age (Ma): 2577 (0)
  • description: Iringa area,Archaean amphibolite; for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
Tixhr 1404322662 thumb IRA19 < 20181010103119-837210 >pub
  • IGSN: IEDRM00S4
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 1.785
  • age (Ma): 2619 (0)
  • description: Iringa area, Archaean granite; for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
Tixhr324074924 thumb IRA24 < 20181010103710-056411 >pub
  • IGSN: IEDRM00S5
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 2.295
  • age (Ma): 2862 (0)
  • description: Iringa area,Archaean granitic gneiss; for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
Tixhr939622168 thumb IRA25 < 20181010103916-195930 >pub
  • IGSN: IEDRM00S6
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 2.445
  • age (Ma): 2506 (0)
  • description: Iringa area, Archaean granitic gneiss; for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
Tixhr 1159005712 thumb IRA22 < 20181010103409-369938 >pub
  • IGSN: IEDRM00S7
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 1.055
  • modified at 2019-11-05
Tixhr 1286941039 thumb IRA4 < 20181001101630-571253 >pub
  • IGSN: IEDRM00S8
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 2.885
  • age (Ma): 2363 (0)
  • description: Iringa area, Proterozoic biotite granite (Hula granite); for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
Tixhr 684471642 thumb IRA7 < 20181001101748-718847 >pub
  • IGSN: IEDRM00S9
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 2.355
  • age (Ma): 2278 (0)
  • description: Iringa area, Proterozoic granite (Hula granite); for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
Tixhr368537931 thumb IRA9 < 20181001101916-682323 >pub
  • IGSN: IEDRM00SA
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 1.6
  • age (Ma): 2208 (0)
  • description: Iringa area, Proterozoic granite; for sample depleted mantle crustal formation age (Tdm) is shown
  • modified at 2019-11-05
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name spots global-id
caption ID assembly stone
Table 2. Rb-Sr whole-rock data pub 20190906093854-887044 strontium (Maboko 1996) 18
Table 1. Sm-Nd whole-rock data pub 20190905153219-840568 Nd_(Maboko,1996) 17
manual
  • name
  • Maboko, M. A. H.
  • Eizo Nakamura