Phanerozoic record of mantle-dominated arc magmatic surges in the Zealandia Cordillera

We integrated new and existing bedrock and detrital zircon dates from the Zealandia Cordillera to explore the tempo of Phanerozoic arc magmatism along the paleo-Pacific margin of southeast Gondwana. We found that episodic magmatism was dominated by two high-magma-addition-rate (MAR) events spaced ~250 m.y. apart in the Devonian (370–368 Ma) and the Early Cretaceous (129–105 Ma). The intervening interval between high-MAR events was characterized by prolonged, low-MAR activity in a geographically stable location for more than 100 m.y. We found that the two high-MAR events in Zealandia have distinct chemistries (S-type for the Devonian and I-type for the Cretaceous) and are unlikely to have been related by a repeating, cyclical process. Like other well-studied arc systems worldwide, the Zealandia Cordillera high-MAR events were associated with upper-plate deformation; however, the magmatic events were triggered by enhanced asthenospheric mantle melting in two distinct arc-tectonic settings—a retreating slab and an advancing slab, respectively. Our results demonstrate that dynamic changes in the subducting slab were primary controls in triggering mantle flare-up events in the Phanerozoic Zealandia Cordillera.

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Early Cretaceous crust–mantle interaction linked to rollback of the Palaeo-Pacific flat-subducting slab: constraints from the intermediate–felsic volcanic rocks of the northern Great Xing’an Range, NE China

Geological Magazine ◽

10.1017/s0016756821000170 ◽

2021 ◽

pp. 1-22

Author(s):

Jia-Hao Jing ◽

Hao Yang ◽

Wen-Chun Ge ◽

Yu Dong ◽

Zheng Ji ◽

...

Keyword(s):

Early Cretaceous ◽

Volcanic Rocks ◽

Geochemical Data ◽

Calc Alkaline ◽

Ne China ◽

Asthenospheric Mantle ◽

High K ◽

Wide Range ◽

Great Xing’An Range ◽

Subducting Slab

Abstract Late Mesozoic igneous rocks are important for deciphering the Mesozoic tectonic setting of NE China. In this paper, we present whole-rock geochemical data, zircon U–Pb ages and Lu–Hf isotope data for Early Cretaceous volcanic rocks from the Tulihe area of the northern Great Xing’an Range (GXR), with the aim of evaluating the petrogenesis and genetic relationships of these rocks, inferring crust–mantle interactions and better constraining extension-related geodynamic processes in the GXR. Zircon U–Pb ages indicate that the rhyolites and trachytic volcanic rocks formed during late Early Cretaceous time (c. 130–126 Ma). Geochemically, the highly fractionated I-type rhyolites exhibit high-K calc-alkaline, metaluminous to weakly peraluminous characteristics. They are enriched in light rare earth elements (LREEs) and large-ion lithophile elements (LILEs) but depleted in high-field-strength elements (HFSEs), with their magmatic zircons ϵHf(t) values ranging from +4.1 to +9.0. These features suggest that the rhyolites were derived from the partial melting of a dominantly juvenile, K-rich basaltic lower crust. The trachytic volcanic rocks are high-K calc-alkaline series and exhibit metaluminous characteristics. They have a wide range of zircon ϵHf(t) values (−17.8 to +12.9), indicating that these trachytic volcanic rocks originated from a dominantly lithospheric-mantle source with the involvement of asthenospheric mantle materials, and subsequently underwent extensive assimilation and fractional crystallization processes. Combining our results and the spatiotemporal migration of the late Early Cretaceous magmatic events, we propose that intense Early Cretaceous crust–mantle interaction took place within the northern GXR, and possibly the whole of NE China, and that it was related to the upwelling of asthenospheric mantle induced by rollback of the Palaeo-Pacific flat-subducting slab.

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Lithosphere thickness controls the extent of mantle melting, depth of melt extraction and basalt compositions in all tectonic settings on Earth – A review and new perspectives

Earth-Science Reviews ◽

10.1016/j.earscirev.2021.103614 ◽

2021 ◽

pp. 103614

Author(s):

Yaoling Niu

Keyword(s):

Mantle Melting ◽

Melting Depth ◽

Melt Extraction ◽

Lithosphere Thickness ◽

Tectonic Settings

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Supplemental Material: Phanerozoic record of mantle-dominated arc magmatic surges in the Zealandia Cordillera

10.1130/geol.s.14772789 ◽

2021 ◽

Author(s):

Mary Ringwood ◽

Joshua J. Schwartz ◽

et al.

Keyword(s):

Detrital Zircon ◽

Analytical Methods ◽

Zircon Geochronology ◽

Addition Rate

Detailed analytical methods and U-Pb zircon geochronology results, zircon cathodoluminescence images, Tera-Wasserburg plots, and tables containing igneous and detrital zircon data and volume addition rate calculations.

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Mantle Dynamics of the Central Atlantic Magmatic Province (CAMP): Constraints from Platinum Group, Gold and Lithophile Elements in Flood Basalts of Morocco

Journal of Petrology ◽

10.1093/petrology/egz041 ◽

2019 ◽

Vol 60 (8) ◽

pp. 1621-1652 ◽

Cited By ~ 3

Author(s):

Christian Tegner ◽

Sandra A T Michelis ◽

Iain McDonald ◽

Eric L Brown ◽

Nasrrddine Youbi ◽

...

Keyword(s):

Mantle Source ◽

Gold Mineralization ◽

Potential Temperature ◽

Primitive Mantle ◽

Mantle Melting ◽

Flood Basalts ◽

Asthenospheric Mantle ◽

Central Atlantic Magmatic Province ◽

Platinum Group ◽

Central Atlantic

Abstract Mantle melting dynamics of the Central Atlantic Magmatic Province (CAMP) is constrained from new platinum group element (PGE), gold (Au), rare earth element (REE), and high field strength element (HFSE) data and geochemical modelling of flood basalts in Morocco. The PGE are enriched similarly to flood basalts of other large igneous provinces. The magmas did not experience sulphide saturation during fractionation and were therefore fertile. The CAMP is thus prospective for PGE and gold mineralization. The Pt/Pd ratio of the Moroccan lavas indicates that they originated by partial melting of the asthenospheric mantle, not the subcontinental lithospheric mantle. Mantle melting modelling of PGE, REE and HFSE suggests the following: (1) the mantle source for all the lavas was dominated by primitive mantle and invariably included a small proportion of recycled continental crust (<8%); (2) the mantle potential temperature was moderately elevated (c. 1430°C) relative to ambient mantle; (3) intra-lava unit compositional variations are probably a combined result of variable amounts of crust in the mantle source (heterogeneous source) and fractional crystallization; (4) mantle melting initially took place at depths between c. 110 and c. 55 km and became shallower with time (c. 110 to c. 32 km depth); (5) the melting region appears to have changed from triangular to columnar with time. These results are best explained by melting of asthenospheric mantle that was mixed with continental sediments during the assembly of Pangaea, then heated and further mixed by convection while insulated under the Pangaea supercontinent, and subsequently melted in multiple continental rift systems associated with the breakup of Pangaea. Most probably the CAMP volcanism was triggered by the arrival of a mantle plume, although plume material apparently was not contributing directly (chemically) to the magmas in Morocco, nor to many other areas of CAMP.

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Overriding-plate deformation during micro-continent accretion

10.5194/egusphere-egu2020-7167 ◽

2020 ◽

Author(s):

Zoltán Erdős ◽

Ritske S. Huismans ◽

Claudio Faccenna

Keyword(s):

Plate Boundary ◽

Slab Thickness ◽

Plate Boundaries ◽

Complex Structures ◽

Model Experiments ◽

Plate Deformation ◽

Convergent Plate Boundaries ◽

The Right ◽

Back Arc ◽

Subducting Slab

Both divergent and convergent plate boundaries had been studied extensively throughout the last five decades. Among a host of other aspects came the realization, that given the right circumstances, a broad extensional basin can form behind a convergent plate boundary. The exact mechanisms triggering back-arc extension and why they are episodic, lasting only for tens of millions of years is still debated. The absolute and relative velocities of the plates, the age of the subducting oceanic plate and the inherited rheological properties of the back-arc lithosphere are all thought to be key players, shaping the dynamics of the fore-arc - back-arc systems.Here we use 2D mantle scale plane-strain thermo-mechanical model experiments to investigate how the accretion of small continental crustal terrains onto the overriding plate affect the dynamics of the subducting slab and the deformation of the overriding plate.Our results suggest that slab-retreat and back-arc extension can be achieved through the combination of slow convergence and micro-continent accretion. Back-arc extension during fast convergence is also possible through the subsequent accretion of more than one micro-continental terrain. Moreover, even the accretion of one such terrain can produce short (1-5 My) episodes of extension-contraction-quiescence in the overriding plate. These episodes are connected to slab break-off events, slab-interaction with upper mantle phase-change boundaries and variations in slab-pull due varying slab thickness.Our model experiments also result in complex structures in the overriding plate where discrete outcrops from a single oceanic basin are preserved on the surface hundreds of kilometres apart. This indicates that in nature a simple accretion scenario could produce a surface geological record that is difficult to decipher. Our results compare favourably to observations from the Aegean back-arc basin.

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Widespread reworking of Hadean-to-Eoarchean continents during Earth’s thermal peak

Nature Communications ◽

10.1038/s41467-020-20514-4 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

C. L. Kirkland ◽

M. I. H. Hartnady ◽

M. Barham ◽

H. K. H. Olierook ◽

A. Steenfelt ◽

...

Keyword(s):

Chemical Composition ◽

Detrital Zircon ◽

Stream Sediment ◽

Mantle Melting ◽

Crustal Growth ◽

Isotopic Data ◽

Sediment Samples ◽

Thermal Peak ◽

Preservation Potential ◽

Refractory Minerals

AbstractThe nature and evolution of Earth’s crust during the Hadean and Eoarchean is largely unknown owing to a paucity of material preserved from this period. However, clues may be found in the chemical composition of refractory minerals that initially grew in primordial material but were subsequently incorporated into younger rocks and sediment during lithospheric reworking. Here we report Hf isotopic data in 3.9 to 1.8 billion year old detrital zircon from modern stream sediment samples from West Greenland, which document successive reworking of felsic Hadean-to-Eoarchean crust during subsequent periods of magmatism. Combined with global zircon Hf data, we show a planetary shift towards, on average, more juvenile Hf values 3.2 to 3.0 billion years ago. This crustal rejuvenation was coincident with peak mantle potential temperatures that imply greater degrees of mantle melting and injection of hot mafic-ultramafic magmas into older Hadean-to-Eoarchean felsic crust at this time. Given the repeated recognition of felsic Hadean-to-Eoarchean diluted signatures, ancient crust appears to have acted as buoyant life-rafts with enhanced preservation-potential that facilitated later rapid crustal growth during the Meso-and-Neoarchean.

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Supplemental Material: Phanerozoic record of mantle-dominated arc magmatic surges in the Zealandia Cordillera

10.1130/geol.s.14772789.v1 ◽

2021 ◽

Author(s):

Mary Ringwood ◽

Joshua J. Schwartz ◽

et al.

Keyword(s):

Detrital Zircon ◽

Analytical Methods ◽

Zircon Geochronology ◽

Addition Rate

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Supplemental Material: Detrital zircon provenance of the Cretaceous–Neogene East Coast Basin reveals changing tectonic conditions and drainage reorganization along the Pacific margin of Zealandia

10.1130/geos.s.17200643 ◽

2021 ◽

Author(s):

J.T. Gooley ◽

N.M. Nieminski

Keyword(s):

Isotopic Composition ◽

Detrital Zircon ◽

East Coast ◽

Mixture Modeling ◽

Systematic Analysis ◽

The Pacific ◽

University Of Arizona ◽

Pb Isotopic Composition ◽

Pacific Margin ◽

The University

<div>Table S1: Data sources for composite basement terranes. Table S2: Relative proportions of age fractions for composite basement terranes. Table S3: U-Th-Pb isotopic composition of detrital zircon analyzed at the University of Arizona LaserChron Center. Table S4: U-Th-Pb isotopic composition of detrital zircon analyzed at the University California, Santa Cruz. Table S5: Relative proportions of age fractions for Cenozoic East Coast Basin cover stratigraphy. Table S6: Relative proportions of age fractions for Cretaceous East Coast Basin cover stratigraphy. Table S7: Mixture modeling results for detrital zircon samples. Figure S1: Map of all samples from the basement terrane and cover stratigraphy with detrital zircon U-Pb ages. File S1: Systematic analysis of mixture modeling results. </div>

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