scholarly journals New zircon radiometric U/Pb ages and Lu-Hf isotopic data from the ultramafic-mafic sequences of Ranau and Telupid (Sabah, east Malaysia): Time to reconsider the geological evolution of Southeast Asia? — REPLY

Geology ◽  
2021 ◽  
Vol 49 (11) ◽  
pp. e542-e542
Author(s):  
Basilios Tsikouras ◽  
Chun-Kit Lai ◽  
Elena Ifandi ◽  
Nur 'Aqidah Norazme ◽  
Chee-Hui Teo ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Isotopic Data ◽  
East Malaysia ◽  
Geological Evolution

Geochemistry and isotopic evolution of the Mesoproterozoic Cape Meredith Complex, West Falkland

2000 ◽  
Vol 137 (5) ◽  
pp. 537-553 ◽  
Author(s):  
ROBERT J. THOMAS ◽  
JOACHIM JACOBS ◽  
BRUCE M. EGLINGTON
Keyword(s):  
High Field ◽  
Alkaline Basalt ◽  
Thin Sheets ◽  
Calc Alkaline ◽  
Isotopic Data ◽  
High Field Strength ◽  
Geological Evolution ◽  
Isotopic Evolution ◽  
Dronning Maud Land ◽  
Granitoid Gneisses

Whole-rock major and trace element geochemical and Rb–Sr/Sm–Nd isotopic data are presented for the Mesoproterozoic (∼1.0 Ga) metamorphic and igneous rocks of the Cape Meredith Complex, West Falkland. The data indicate that the oldest rocks, the ∼1.1 Ga supracrustal gneisses of the Big Cape Formation, which form three petrographic and geochemical groups (mafic amphibolite, quartz–plagioclase–biotite–hornblende intermediate gneiss and acid gneiss), probably represent a juvenile calc-alkaline, basalt–andesite–rhyolite volcanic sequence, with epsilon (εNdT) values and NdTDM ages of ∼+3 to +6 and ∼1100 to 1400 Ma respectively. It is argued on geochemical grounds that these metavolcanics were extruded in an island-arc at around 1120 Ma. The Big Cape Formation was intruded by granitoids during and after a collisional orogenic event at around 1090 Ma. The oldest, foliated, (G1) granodiorite was emplaced as thin sheets at approximately 1090 to 1070 Ma and is characterized by εNd values of ∼+1.5 to 4 (TDM = ∼1200 to 1400 Ma), showing its juvenile nature. The ∼1070 Ma (G2) syntectonic granitoid gneisses and ∼1000 Ma G3 post-tectonic granites also exhibit juvenile characteristics (εNd = ∼0 to +5 and TDM = 2200 to 1200 Ma, respectively). The granitoids show a time-composition evolution from Na-rich (G1) granodiorite to potassic, high-High Field Strength Element granites (G3). The geochemical and isotopic characteristics and geological evolution of the Cape Meredith Complex is comparable with that of the adjacent Gondwana crustal blocks in Natal (SE Africa) and Dronning Maud Land (East Antarctica), supporting models that demonstrate these areas evolved in a contiguous, juvenile arc environment prior to, and during, a major orogenic event at ∼1.1 Ga. These events were associated with the birth of the Rodinian supercontinent. The three areas remained juxtaposed during Rodinia break-up and were subsequently incorporated into Gondwana in the same relative positions.

scholarly journals New zircon radiometric U-Pb ages and Lu-Hf isotopic data from the ultramafic-mafic sequences of Ranau and Telupid (Sabah, eastern Malaysia): Time to reconsider the geological evolution of Southeast Asia?

Geology ◽  
2021 ◽  
Author(s):  
Basilios Tsikouras ◽  
Chun-Kit Lai ◽  
Elena Ifandi ◽  
Nur’Aqidah Norazme ◽  
Chee-Hui Teo ◽  
...  
Keyword(s):  
Ultramafic Rocks ◽  
Crustal Material ◽  
Isotopic Data ◽  
Backarc Basin ◽  
Crustal Component ◽  
Sulu Sea ◽  
Potential Source ◽  
Depleted Mantle ◽  
Geological Evolution ◽  
Mantle Reservoir

New zircon U-Pb geochronology from a peridotite suite near Ranau and the Telupid ophiolite in Sabah, eastern Malaysia, contradict previous studies, which assumed that the Sabah mafic-ultramafic rocks are largely ophiolitic and Jurassic–Cretaceous in age. We show that these rocks formed during a magmatic episode in the Miocene (9.2–10.5 Ma), which is interpreted to reflect infiltration of melts and melt-rock reaction in the Ranau subcontinental peridotites during extension, and concurrent seafloor spreading forming the Telupid ophiolite further south. Older zircons from the Ranau peridotites have Cretaceous, Devonian, and Neoproterozoic ages. Zircon Lu-Hf isotopic data suggest their derivation from a depleted mantle. However, significant proportions of crustal components have been incorporated in their genesis, as evidenced by their less-radiogenic Hf signature compared to a pristine mantle reservoir. The involvement of a crustal component is consistent with our interpreted continental setting for the Ranau peridotite and formation in a narrow backarc basin for the Telupid ophiolite. We infer that the Sulu Sea, which was expanding throughout much of the Miocene, may have extended to the southwest into central Sabah. The Telupid oceanic strand formed during the split, collapse, and rollback of the Sulu arc due to the subduction of the Celebes Sea beneath Sabah. Incorporation of the Sulu arc in the evolving Miocene oceanic basin is a potential source to explain the involvement of crustal material in the zircon evolution of the Telupid ophiolite.

On The Possibility of an Autonomous History of Modern Southeast Asia

1961 ◽  
Vol 2 (2) ◽  
pp. 73-105 ◽  
Author(s):  
John R. W. Small
Keyword(s):  
Southeast Asia ◽  
Contemporary History ◽  
The Past ◽  
History Of

It is generally accepted that history is an element of culture and the historian a member of society, thus, in Croce's aphorism, that the only true history is contemporary history. It follows from this that when there occur great changes in the contemporary scene, there must also be great changes in historiography, that the vision not merely of the present but also of the past must change.

Sign in / Sign up

Export Citation Format

Share Document