Neogene Extension and Exhumation in NW Sulawesi. / Advokaat, Eldert; Hall, Robert; White, Lloyd; Armstrong, Richard; Kohn, B.P.; BouDagher-Fadel, Marcelle K. .

2014. T43A-4701.

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Neogene Extension and Exhumation in NW Sulawesi. / Advokaat, Eldert; Hall, Robert; White, Lloyd; Armstrong, Richard; Kohn, B.P.; BouDagher-Fadel, Marcelle K. .

2014. T43A-4701.

Research output: Contribution to conferenceAbstractpeer-review

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Advokaat E, Hall R, White L, Armstrong R, Kohn BP, BouDagher-Fadel MK. Neogene Extension and Exhumation in NW Sulawesi. 2014.

Author

Advokaat, Eldert ; Hall, Robert ; White, Lloyd ; Armstrong, Richard ; Kohn, B.P. ; BouDagher-Fadel, Marcelle K. . / Neogene Extension and Exhumation in NW Sulawesi.

BibTeX

@conference{f78ef5d5576e4c2aa7aa323bf48c0466,
title = "Neogene Extension and Exhumation in NW Sulawesi",
abstract = "The unusual K-shaped island of Sulawesi, located in the convergent zone between the Eurasian, Australian and Pacific plates, has traditionally been interpreted as the consequence of collision and accretion. New data challenge this idea and indicate that crustal extension has played an important role in its Neogene development.In the north of the Sulawesi North Arm are Eocene–Lower Miocene basalts intercalated with radiolarian chert and volcaniclastic sediments, which were deformed during collision of the Sula Spur with the North Arm. Undeformed granitoids derived from lower crustal rocks intrude the sequence and preliminary LA-ICP-MS U-Pb zircon ages decrease from 9.44±0.43 Ma in the north to 8.19±0.20 Ma in the south.Structurally beneath all these rocks is the Malino Metamorphic Complex (MMC) which exposes dominantly quartzo-feldspathic muscovite schists to gneisses, with subordinate amphibolites and garnet schists. The MMC is a metamorphic core complex, surrounded by a discontinuous greenschist carapace and shear zones with opposite shear senses on the northern and southern sides of the complex. Metamorphic rocks from the MMC yield SHRIMP U-Pb ages on zircon rims of 15.42±0.62 Ma and 15.36±0.53 Ma. Locally these metamorphic rocks are intruded by undeformed granitoids with SHRIMP U-Pb zircon ages of 4.85 ± 0.07 to 3.78±0.04 Ma. Late stage exhumation accommodated by high angle oblique normal faults is indicated by apatite (U-Th)/He ages between 3.26±0.23 Ma and 1.43±0.24 Ma, at a rate of 0.27 mm/a based on age-elevation plots.Lower Pliocene–Lower Pleistocene syn-extensional shallow marine siliciclastic and carbonate sediments are crosscut by normal faults. The timing of faulting and lack of metamorphic detritus in these young sediments support rapid and recent regional uplift. We interpret two phases of extension in North Sulawesi, one during the Middle Miocene and another during the Late Pliocene-Pleistocene, exhuming the granitic and metamorphic rocks.",
author = "Eldert Advokaat and Robert Hall and Lloyd White and Richard Armstrong and B.P. Kohn and BouDagher-Fadel, {Marcelle K.}",
year = "2014",
language = "English",
pages = "T43A--4701",

}

RIS

TY - CONF

T1 - Neogene Extension and Exhumation in NW Sulawesi

AU - Advokaat, Eldert

AU - Hall, Robert

AU - White, Lloyd

AU - Armstrong, Richard

AU - Kohn, B.P.

AU - BouDagher-Fadel, Marcelle K.

PY - 2014

Y1 - 2014

N2 - The unusual K-shaped island of Sulawesi, located in the convergent zone between the Eurasian, Australian and Pacific plates, has traditionally been interpreted as the consequence of collision and accretion. New data challenge this idea and indicate that crustal extension has played an important role in its Neogene development.In the north of the Sulawesi North Arm are Eocene–Lower Miocene basalts intercalated with radiolarian chert and volcaniclastic sediments, which were deformed during collision of the Sula Spur with the North Arm. Undeformed granitoids derived from lower crustal rocks intrude the sequence and preliminary LA-ICP-MS U-Pb zircon ages decrease from 9.44±0.43 Ma in the north to 8.19±0.20 Ma in the south.Structurally beneath all these rocks is the Malino Metamorphic Complex (MMC) which exposes dominantly quartzo-feldspathic muscovite schists to gneisses, with subordinate amphibolites and garnet schists. The MMC is a metamorphic core complex, surrounded by a discontinuous greenschist carapace and shear zones with opposite shear senses on the northern and southern sides of the complex. Metamorphic rocks from the MMC yield SHRIMP U-Pb ages on zircon rims of 15.42±0.62 Ma and 15.36±0.53 Ma. Locally these metamorphic rocks are intruded by undeformed granitoids with SHRIMP U-Pb zircon ages of 4.85 ± 0.07 to 3.78±0.04 Ma. Late stage exhumation accommodated by high angle oblique normal faults is indicated by apatite (U-Th)/He ages between 3.26±0.23 Ma and 1.43±0.24 Ma, at a rate of 0.27 mm/a based on age-elevation plots.Lower Pliocene–Lower Pleistocene syn-extensional shallow marine siliciclastic and carbonate sediments are crosscut by normal faults. The timing of faulting and lack of metamorphic detritus in these young sediments support rapid and recent regional uplift. We interpret two phases of extension in North Sulawesi, one during the Middle Miocene and another during the Late Pliocene-Pleistocene, exhuming the granitic and metamorphic rocks.

AB - The unusual K-shaped island of Sulawesi, located in the convergent zone between the Eurasian, Australian and Pacific plates, has traditionally been interpreted as the consequence of collision and accretion. New data challenge this idea and indicate that crustal extension has played an important role in its Neogene development.In the north of the Sulawesi North Arm are Eocene–Lower Miocene basalts intercalated with radiolarian chert and volcaniclastic sediments, which were deformed during collision of the Sula Spur with the North Arm. Undeformed granitoids derived from lower crustal rocks intrude the sequence and preliminary LA-ICP-MS U-Pb zircon ages decrease from 9.44±0.43 Ma in the north to 8.19±0.20 Ma in the south.Structurally beneath all these rocks is the Malino Metamorphic Complex (MMC) which exposes dominantly quartzo-feldspathic muscovite schists to gneisses, with subordinate amphibolites and garnet schists. The MMC is a metamorphic core complex, surrounded by a discontinuous greenschist carapace and shear zones with opposite shear senses on the northern and southern sides of the complex. Metamorphic rocks from the MMC yield SHRIMP U-Pb ages on zircon rims of 15.42±0.62 Ma and 15.36±0.53 Ma. Locally these metamorphic rocks are intruded by undeformed granitoids with SHRIMP U-Pb zircon ages of 4.85 ± 0.07 to 3.78±0.04 Ma. Late stage exhumation accommodated by high angle oblique normal faults is indicated by apatite (U-Th)/He ages between 3.26±0.23 Ma and 1.43±0.24 Ma, at a rate of 0.27 mm/a based on age-elevation plots.Lower Pliocene–Lower Pleistocene syn-extensional shallow marine siliciclastic and carbonate sediments are crosscut by normal faults. The timing of faulting and lack of metamorphic detritus in these young sediments support rapid and recent regional uplift. We interpret two phases of extension in North Sulawesi, one during the Middle Miocene and another during the Late Pliocene-Pleistocene, exhuming the granitic and metamorphic rocks.

M3 - Abstract

SP - T43A-4701

ER -