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.
| Original language | English |
|---|---|
| Pages (from-to) | 227-242 |
| Number of pages | 16 |
| Journal | Precambrian Research |
| Volume | 113 |
| Issue number | 3-4 |
| DOIs | |
| Publication status | Published - Jan 31 2002 |
Fingerprint
Keywords
- Crust formation
- Granulites
- Mozambique Belt
- Sm-Nd geochronology
- Tanzania
ASJC Scopus subject areas
- Geochemistry and Petrology
- Geology
Cite this
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. / Maboko, M. A H; Nakamura, Eizou.
In: Precambrian Research, Vol. 113, No. 3-4, 31.01.2002, p. 227-242.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Isotopic dating of Neoproterozoic crustal growth in the Usambara Mountains of northeastern Tanzania
T2 - Evidence for coeval crust formation in the Mozambique Belt and the Arabian-Nubian Shield
AU - Maboko, M. A H
AU - Nakamura, Eizou
PY - 2002/1/31
Y1 - 2002/1/31
N2 - 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.
AB - 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.
KW - Crust formation
KW - Granulites
KW - Mozambique Belt
KW - Sm-Nd geochronology
KW - Tanzania
UR - http://www.scopus.com/inward/record.url?scp=0037204147&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0037204147&partnerID=8YFLogxK
U2 - 10.1016/S0301-9268(01)00213-3
DO - 10.1016/S0301-9268(01)00213-3
M3 - Article
VL - 113
SP - 227
EP - 242
JO - Precambrian Research
JF - Precambrian Research
SN - 0301-9268
IS - 3-4
ER -