Maboko, M. A. H. & Nakamura, Eizo (2002) Isotopic dating of Neoproterozoic crustal growth in the Usambara Mountains of Northeastern Tanzania: evidence for coeval crust formation in the Mozambique Belt and the Arabian–Nubian Shield, Precambrian Research, 113, 227-242, doi: 10.1016/S0301-9268(01)00213-3. < 20180919154203-212867 > pub

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

  • abstract:

    Granulite-facies orthogneisses of andesitic to dacitic composition in the Usambara Mountains of north eastern Tanzania yield a Sm–Nd whole rock isochron age of 815±58 Ma and an initial ε(Nd) value of 4.1. This age is interpreted as dating Sm–Nd fractionation during extraction from the mantle and immediate subsequent crystallisation of the granulite protolith during an event of regional calc-alkaline magmatism in the area. Isotopic and geochemical characteristics of the rocks are consistent with a convergent margin setting for the magmatism with minimal contamination by older continental crust. The isotopic data from the Usambara Mountains demonstrate that Neoproterozoic crust formation in the Arabian–Nubian Shield and parts of the Mozambique Belt was broadly contemporaneous.

  • doi: 10.1016/S0301-9268(01)00213-3
  • modified at 3 h ago


(a) TIMS on TIMS Thermo-Fisher MAT261


(a) TIMS on TIMS Thermo-Fisher MAT261


(a) XRF on XRF PANalytical PW2400
(b) Q-ICP-MS_procedures of Makishima and Nakamura (1997, 1999, 2006) on ICPMS Yokogawa PMS2000
Tixhr1729427763 thumb US1 < 20181002094006-090506 >pub
  • IGSN: IEDRM00SB
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 2.315
  • age (Ma): 1001 (0)
  • description: Usambara granulite complex; depleted mantle crustal formation age (Tdm) is shown for sample
  • modified at 2019-11-05
Tixhr131149667 thumb US3 < 20181002094324-513005 >pub
  • IGSN: IEDRM00SC
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 1.145
  • age (Ma): 1068 (0)
  • description: Usambara granulite complex; depleted mantle crustal formation age (Tdm) is shown for sample
  • modified at 2019-11-05
Tixhr 203293378 thumb US4 < 20181002094442-012443 >pub
  • IGSN: IEDRM00SD
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 3.01
  • age (Ma): 1044 (0)
  • description: Usambara granulite complex; depleted mantle crustal formation age (Tdm) is shown for sample
  • modified at 2019-11-05
Tixhr140969842 thumb US5 < 20181002094637-946922 >pub
  • IGSN: IEDRM00SE
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 2.995
  • age (Ma): 971 (0)
  • description: Usambara granulite; the garnets yield ages ranging from 618 to 650 Ma; depleted mantle crustal formation age (Tdm) is shown for sample
  • modified at 2019-11-05
Tixhr 396456301 thumb US6 < 20181002094831-575761 >pub
  • IGSN: IEDRM00SF
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 1.57
  • age (Ma): 1068 (0)
  • description: Usambara granulite; the garnets yield ages ranging from 581 to 611 Ma; depleted mantle crustal formation age (Tdm) is shown for sample
  • modified at 2019-11-05
Tixhr1792052240 thumb US9B < 20180927152859-657400 >pub
  • IGSN: IEDRM00SG
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 1.49
  • age (Ma): 1036 (0)
  • description: Usambara granulite; coarse; the garnets yield ages ranging from 578 to 606 Ma; depleted mantle crustal formation age (Tdm) is shown for sample
  • modified at 2019-11-05
Tixhr 1519081847 thumb 9L < 20181002102524-004113 >pub
  • IGSN: IEDRM00SH
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 0.355
  • age (Ma): 1044 (0)
  • description: Usambara granulite complex; depleted mantle crustal formation age (Tdm) is shown for sample
  • modified at 2019-11-05
Tixhr 1756203494 thumb US10 < 20181004100544-181453 >pub
  • IGSN: IEDRM00SI
  • classification: metamorphic
  • physical-form: hand specimen
  • quantity (kg): 4.16
  • age (Ma): 1057 (0)
  • description: Usambara granulite complex; depleted mantle crustal formation age (Tdm) is shown for sample
  • modified at 2019-11-05
name device size global-id
US1 pub ICPMS Yokogawa PMS2000 26 20190906143350-611372
US1 pub XRF PANalytical PW2400 13 20190906120237-292977
US1 pub TIMS Thermo-Fisher MAT261 5 20190906144009-166003
US1 pub TIMS Thermo-Fisher MAT261 5 20190906145855-629717
US3 pub XRF PANalytical PW2400 13 20190906120237-966480
US3 pub ICPMS Yokogawa PMS2000 26 20190906143351-953914
US3 pub TIMS Thermo-Fisher MAT261 5 20190906144009-459049
US3 pub TIMS Thermo-Fisher MAT261 5 20190906145855-228203
US4 pub ICPMS Yokogawa PMS2000 26 20190906143351-094580
US4 pub XRF PANalytical PW2400 13 20190906120238-244538
US4 pub TIMS Thermo-Fisher MAT261 5 20190906144009-507965
US4 pub TIMS Thermo-Fisher MAT261 5 20190906145855-413948
US5 pub XRF PANalytical PW2400 13 20190906120238-167250
US5 pub ICPMS Yokogawa PMS2000 26 20190906143352-357519
US5 pub TIMS Thermo-Fisher MAT261 5 20190906144009-951426
US5 pub TIMS Thermo-Fisher MAT261 5 20190906145855-829612
US6 pub XRF PANalytical PW2400 13 20190906120238-545545
US6 pub ICPMS Yokogawa PMS2000 26 20190906143352-158749
US6 pub TIMS Thermo-Fisher MAT261 5 20190906144010-075525
US6 pub TIMS Thermo-Fisher MAT261 5 20190906145855-715193
US9B pub XRF PANalytical PW2400 13 20190906120239-610109
US9B pub ICPMS Yokogawa PMS2000 26 20190906143353-264563
US9B pub TIMS Thermo-Fisher MAT261 5 20190906144010-628368
US9B pub TIMS Thermo-Fisher MAT261 5 20190906145856-175110
9L pub XRF PANalytical PW2400 13 20190906120239-781064
9L pub ICPMS Yokogawa PMS2000 26 20190906143353-104768
9L pub TIMS Thermo-Fisher MAT261 5 20190906144010-990412
9L pub TIMS Thermo-Fisher MAT261 5 20190906145856-598356
US10 pub XRF PANalytical PW2400 13 20190906120239-757198
US10 pub ICPMS Yokogawa PMS2000 26 20190906143354-854286
US10 pub TIMS Thermo-Fisher MAT261 5 20190906144010-562071
US10 pub TIMS Thermo-Fisher MAT261 5 20190906145856-953444
name spots global-id
caption ID assembly stone
Table 4. Sm-Nd data pub 20190906144043-759412 Nd_(Maboko,2002) 8
Table 5. Rb-Sr data pub 20190906150028-191330 Sr (Maboko, 2002) 8
Table 2. Major element (in wt.%) and trace element (in ppm) composition pub 20190906120124-157474 major-trace (Maboko, 2002) 8
manual
  • name
  • Maboko, M. A. H.
  • Nakamura, Eizo