The thermo-tectonic evolution of the actively exhuming Mai'iu Fault footwall – Suckling-Dayman metamorphic core complex – in the Woodlark Rift of Papua New Guinea

2021 ◽  
pp. 228856
Author(s):  
J.E. Österle ◽  
D. Seward ◽  
D.F. Stockli ◽  
T.A. Little ◽  
J.S. Rooney ◽  
...  
Keyword(s):  
Papua New Guinea ◽  
Tectonic Evolution ◽  
New Guinea ◽  
Metamorphic Core Complex ◽  
Core Complex ◽  
Metamorphic Core

Exhumation of the Dayman dome metamorphic core complex, eastern Papua New Guinea

2009 ◽  
Vol 27 (6) ◽  
pp. 405-422 ◽  
Author(s):  
N. R. DACZKO ◽  
P. CAFFI ◽  
J. A. HALPIN ◽  
P. MANN
Keyword(s):  
Papua New Guinea ◽  
New Guinea ◽  
Metamorphic Core Complex ◽  
Core Complex ◽  
Metamorphic Core

Evolution of a rapidly slipping, active low-angle normal fault, Suckling-Dayman metamorphic core complex, SE Papua New Guinea

2019 ◽  
Vol 131 (7-8) ◽  
pp. 1333-1363 ◽  
Author(s):  
Timothy A. Little ◽  
S.M. Webber ◽  
M. Mizera ◽  
C. Boulton ◽  
J. Oesterle ◽  
...  
Keyword(s):  
Papua New Guinea ◽  
Normal Fault ◽  
New Guinea ◽  
Metamorphic Core Complex ◽  
Core Complex ◽  
Metamorphic Core

The petrology, geochronology and tectono-magmatic setting of igneous rocks in the Suckling-Dayman metamorphic core complex, Papua New Guinea

2020 ◽  
Vol 83 ◽  
pp. 390-414 ◽  
Author(s):  
J.E. Ӧsterle ◽  
T.A. Little ◽  
D. Seward ◽  
D.F. Stockli ◽  
J. Gamble
Keyword(s):  
Papua New Guinea ◽  
New Guinea ◽  
Metamorphic Core Complex ◽  
Igneous Rocks ◽  
Core Complex ◽  
Metamorphic Core

scholarly journals The thermo-tectonic evolution of the Suckling-Dayman metamorphic core complex, southeastern Papua New Guinea

2021 ◽  
Author(s):  
◽  
Jürgen Österle
Keyword(s):  
Papua New Guinea ◽  
Slip Rate ◽  
Carbonaceous Material ◽  
Metamorphic Core Complex ◽  
Calc Alkaline ◽  
Core Complex ◽  
Igneous Complex ◽  
Fault Trace ◽  
Initial Dip ◽  
Metamorphic Core

<p>The Suckling-Dayman metamorphic core complex (SDMCC) in the Woodlark Rift of southeastern Papua New Guinea is being exhumed along the Mai’iu Fault, an active low-angle normal fault dipping ~20-22° northwards at the surface. The spectacularly smooth topography of the Mai’iu Fault footwall clearly is expressive of geologically recent uplift. The precise timing and rates of the exhumation of this continental metamorphic core complex (MCC) have, however, never been studied in detail. This thesis provides the first systematic set of U-Pb, fission track (FT), (U-Th[-Sm])/He and ²⁶Al/¹⁰Be ages from metaigneous and metasedimentary rocks of the footwall of the SDMCC, clasts and a tephra deposit contained within syn-tectonic conglomerates (the Gwoira Conglomerate) in a rider block, and modern stream sediments in the footwall and hanging wall of the Mai’iu Fault. The ages are complemented by whole-rock compositional and thermobarometric data (Al-in-amphibole, Al-in-biotite, Raman spectroscopy of carbonaceous material). Based on these data, the timing of the onset of extension along the Mai’iu Fault, its long-term dip-slip rate and its initial dip were constrained. These data are presented in the context of the evolution of the SDMCC from the Cretaceous to the present.  The dominant lithology of the SDMCC, the Goropu Metabasalt, formed in a marginal basin to the northeast of the Australian continent. Two zircon U-Pb ages of 103.0 ± 5.7 and 71.6 ± 3.3 Ma, indicative of maximum depositional ages, from metasedimentary intercalations (the Bonenau Schist) in the Goropu Metabasalt, suggest formation of the oceanic protolith in the Late Cretaceous. Between 60.4 ± 2.5 and 56.6 ± 2.3 Ma (zircon U-Pb), tholeiitic to mildly calc-alkaline gabbroic to tonalitic rocks of the Yau Igneous Complex intruded the Goropu Metabasalt. The age of the Yau Igneous Complex overlaps with the known timing of north-directed subduction of the oceanic lithosphere along the Owen Stanley Fault (OSF) beneath the Cape Vogel Arc and provides a minimum age for the oceanic protolith.  A second phase of magmatism, consisting of peraluminous-metaluminous calc-alkaline (Suckling Granite) and high-K (Mai’iu Monzonite, Bonua Porphyry) granitoids and basaltic andesite dikes that were cut by the Mai’iu Fault, was associated with the tectonic inversion of the OSF. Zircons from these syn-extensional intrusions suggest crystallization between 3.8 ± 0.2 and 2.0 ± 0.1 Ma. The oldest age of this range is inferred to mark the time by which the OSF had been re-activated as an extensional structure, the Mai’iu Fault. Al-in-amphibole and -biotite thermobarometry suggests crystallization of the Suckling Granite and Mai’iu Monzonite in a relatively shallow crust (~2-8 km depth) at pressures of ~0.4-2.3 kbar. Inherited zircons in the Plio-Pleistocene granitoids indicate that the Goropu Metabasalt carapace of the SDMCC is underlain by Australian-derived Cretaceous crustal material that is inferred to be the continuation of the Kagi Metamorphics in the central Papuan Peninsula.  Further constraints of the timing of unroofing of the SDMCC were determined from three quartz clasts in the Gwoira Conglomerate. ²⁶Al/¹⁰Be burial ages of these samples indicate deposition in the Pliocene between 4.6 ± 2.9 and 3.4 ± 2.1 Ma. A tephra in the upper section of the exposed conglomerates was dated employing U-Pb methods on zircon, combined with apatite, zircon and magnetite (U-Th[-Sm])/He chronometers, yielding a complex age spectrum. An eruption age of 0.6 ± 0.4 Ma was extrapolated for this tephra. FT and (U-Th[-Sm])/He low-temperature thermochronometry details a young (≤3 Ma) and rapid exhumation history. Based on the crystallization ages of the syn-extensional granitoids, the depositional age of the Gwoira Conglomerate, the extensional cooling recorded by low-temperature thermochronometry, and the backwards projection of the published Holocene dip-slip rate of the Mai’iu Fault, the timing of the onset of extension is estimated at ~4 Ma.  A minimum dip-slip rate of 8.1 ± 1.3 km/myr has been calculated from the inverse slope of zircon (U-Th)/He (ZHe) ages with slip-parallel distance from Mai’iu Fault trace. This is slightly lower than the >12 km/myr required to restore the intrusion depths (2-8 km) of the syn-extensional granitoids, now exposed 20-25 km south of the Mai’iu Fault trace at elevations up to 3.4 km. Collectively, these constraints suggest that the Mai’iu Fault has moved at cm-per-year rates since ~3 Ma.  Evidence for both a fossil zircon FT (ZFT) partial annealing zone (PAZ) and a ZHe partial retention zone (PRZ) on the footwall of the SDMCC is presented. Combining paleo-temperature estimates from the inferred bases of the zircon PAZ and PRZ, peak-metamorphic temperatures inferred from Raman spectroscopy of carbonaceous material (RSCM), and published peak-metamorphic temperature constraints on the extensional shear zone mylonites near the Mai’iu Fault trace, a minimum slip-parallel, down-dip paleo-temperature gradient of 9.7 ± 2.2°C/km has been estimated for the exhumed Mai’iu Fault plane. Assuming that the modern regional geothermal gradient in the Woodlark Rift is a maximum estimate of that which existed prior to extensional exhumation of the SDMCC, the paleo-temperature gradient was used to estimate an average initial dip of the Mai’iu Fault of ~44° for pre-extensional geothermal gradients ranging between 10 to 20°C/km. Presently dipping 20-22° at the surface, the constraints on the initial dip suggest that the Mai’iu Fault may have been back-rotated by >20° since the onset of extension, consistent with a rolling hinge-style evolution of this continental MCC.</p>

scholarly journals The thermo-tectonic evolution of the Suckling-Dayman metamorphic core complex, southeastern Papua New Guinea

2021 ◽  
Author(s):  
◽  
Jürgen Österle
Keyword(s):  
Papua New Guinea ◽  
Slip Rate ◽  
Carbonaceous Material ◽  
Metamorphic Core Complex ◽  
Calc Alkaline ◽  
Core Complex ◽  
Igneous Complex ◽  
Fault Trace ◽  
Initial Dip ◽  
Metamorphic Core

<p>The Suckling-Dayman metamorphic core complex (SDMCC) in the Woodlark Rift of southeastern Papua New Guinea is being exhumed along the Mai’iu Fault, an active low-angle normal fault dipping ~20-22° northwards at the surface. The spectacularly smooth topography of the Mai’iu Fault footwall clearly is expressive of geologically recent uplift. The precise timing and rates of the exhumation of this continental metamorphic core complex (MCC) have, however, never been studied in detail. This thesis provides the first systematic set of U-Pb, fission track (FT), (U-Th[-Sm])/He and ²⁶Al/¹⁰Be ages from metaigneous and metasedimentary rocks of the footwall of the SDMCC, clasts and a tephra deposit contained within syn-tectonic conglomerates (the Gwoira Conglomerate) in a rider block, and modern stream sediments in the footwall and hanging wall of the Mai’iu Fault. The ages are complemented by whole-rock compositional and thermobarometric data (Al-in-amphibole, Al-in-biotite, Raman spectroscopy of carbonaceous material). Based on these data, the timing of the onset of extension along the Mai’iu Fault, its long-term dip-slip rate and its initial dip were constrained. These data are presented in the context of the evolution of the SDMCC from the Cretaceous to the present.  The dominant lithology of the SDMCC, the Goropu Metabasalt, formed in a marginal basin to the northeast of the Australian continent. Two zircon U-Pb ages of 103.0 ± 5.7 and 71.6 ± 3.3 Ma, indicative of maximum depositional ages, from metasedimentary intercalations (the Bonenau Schist) in the Goropu Metabasalt, suggest formation of the oceanic protolith in the Late Cretaceous. Between 60.4 ± 2.5 and 56.6 ± 2.3 Ma (zircon U-Pb), tholeiitic to mildly calc-alkaline gabbroic to tonalitic rocks of the Yau Igneous Complex intruded the Goropu Metabasalt. The age of the Yau Igneous Complex overlaps with the known timing of north-directed subduction of the oceanic lithosphere along the Owen Stanley Fault (OSF) beneath the Cape Vogel Arc and provides a minimum age for the oceanic protolith.  A second phase of magmatism, consisting of peraluminous-metaluminous calc-alkaline (Suckling Granite) and high-K (Mai’iu Monzonite, Bonua Porphyry) granitoids and basaltic andesite dikes that were cut by the Mai’iu Fault, was associated with the tectonic inversion of the OSF. Zircons from these syn-extensional intrusions suggest crystallization between 3.8 ± 0.2 and 2.0 ± 0.1 Ma. The oldest age of this range is inferred to mark the time by which the OSF had been re-activated as an extensional structure, the Mai’iu Fault. Al-in-amphibole and -biotite thermobarometry suggests crystallization of the Suckling Granite and Mai’iu Monzonite in a relatively shallow crust (~2-8 km depth) at pressures of ~0.4-2.3 kbar. Inherited zircons in the Plio-Pleistocene granitoids indicate that the Goropu Metabasalt carapace of the SDMCC is underlain by Australian-derived Cretaceous crustal material that is inferred to be the continuation of the Kagi Metamorphics in the central Papuan Peninsula.  Further constraints of the timing of unroofing of the SDMCC were determined from three quartz clasts in the Gwoira Conglomerate. ²⁶Al/¹⁰Be burial ages of these samples indicate deposition in the Pliocene between 4.6 ± 2.9 and 3.4 ± 2.1 Ma. A tephra in the upper section of the exposed conglomerates was dated employing U-Pb methods on zircon, combined with apatite, zircon and magnetite (U-Th[-Sm])/He chronometers, yielding a complex age spectrum. An eruption age of 0.6 ± 0.4 Ma was extrapolated for this tephra. FT and (U-Th[-Sm])/He low-temperature thermochronometry details a young (≤3 Ma) and rapid exhumation history. Based on the crystallization ages of the syn-extensional granitoids, the depositional age of the Gwoira Conglomerate, the extensional cooling recorded by low-temperature thermochronometry, and the backwards projection of the published Holocene dip-slip rate of the Mai’iu Fault, the timing of the onset of extension is estimated at ~4 Ma.  A minimum dip-slip rate of 8.1 ± 1.3 km/myr has been calculated from the inverse slope of zircon (U-Th)/He (ZHe) ages with slip-parallel distance from Mai’iu Fault trace. This is slightly lower than the >12 km/myr required to restore the intrusion depths (2-8 km) of the syn-extensional granitoids, now exposed 20-25 km south of the Mai’iu Fault trace at elevations up to 3.4 km. Collectively, these constraints suggest that the Mai’iu Fault has moved at cm-per-year rates since ~3 Ma.  Evidence for both a fossil zircon FT (ZFT) partial annealing zone (PAZ) and a ZHe partial retention zone (PRZ) on the footwall of the SDMCC is presented. Combining paleo-temperature estimates from the inferred bases of the zircon PAZ and PRZ, peak-metamorphic temperatures inferred from Raman spectroscopy of carbonaceous material (RSCM), and published peak-metamorphic temperature constraints on the extensional shear zone mylonites near the Mai’iu Fault trace, a minimum slip-parallel, down-dip paleo-temperature gradient of 9.7 ± 2.2°C/km has been estimated for the exhumed Mai’iu Fault plane. Assuming that the modern regional geothermal gradient in the Woodlark Rift is a maximum estimate of that which existed prior to extensional exhumation of the SDMCC, the paleo-temperature gradient was used to estimate an average initial dip of the Mai’iu Fault of ~44° for pre-extensional geothermal gradients ranging between 10 to 20°C/km. Presently dipping 20-22° at the surface, the constraints on the initial dip suggest that the Mai’iu Fault may have been back-rotated by >20° since the onset of extension, consistent with a rolling hinge-style evolution of this continental MCC.</p>

Thermochronologic constraints on the tectonic evolution of active metamorphic core complexes, D'entrecasteaux Islands, Papua New Guinea

Tectonics ◽  
1993 ◽  
Vol 12 (3) ◽  
pp. 611-628 ◽  
Author(s):  
Suzanne L. Baldwin ◽  
Gordon S. Lister ◽  
E. June Hill ◽  
David A. Foster ◽  
Ian McDougall
Keyword(s):  
Papua New Guinea ◽  
Tectonic Evolution ◽  
New Guinea ◽  
Metamorphic Core Complexes ◽  
Metamorphic Core
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