Intermediate P/T-type regional metamorphism of the Isua Supracrustal Belt, southern west Greenland: The oldest Pacific-type orogenic belt?

Arai, T; Omori, Soichi; Komiya, Tsuyoshi; Maruyama, Shigenori

doi:10.1016/j.tecto.2015.05.020

Cited by 22 publications

(67 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Namely, all prior detailed geologic studies of our best-preserved Eoarchean terrane, the ca. 3.85-3.60 Ga Isua supracrustal belt of SW Greenland, interpret this site to record terrane collision within the context of plate tectonics (Arai et al, 2015;Hanmer and Greene, 2002;Komiya et al, 1999;Nutman et al, 2015b;. It is worth considering that an individual record of subduction and terrane collision does not require global plate tectonics; for example, proposed Venusian subduction at the Artemis corona is spatially restricted within an otherwise stagnant lid setting (Davaille et al, 2017).…”

Section: Introductionmentioning

confidence: 94%

“…3.7 Ga stratigraphic sequences and flanking TTG bodies to infer a suture zone and/or accretionary complex along the ~35 km length of the Isua supracrustal belt, with initial collision prior to intrusion of small volumes of ca. 3.66-3.60 Ga granites observed in all rock packages (e.g., Arai et al, 2015;. Despite agreement on an overarching plate-tectonic setting, basic aspects of the geometric, kinematic, and petrologic framework of Isua are disputed.…”

Section: Geological Backgroundmentioning

confidence: 99%

“…2A; Arai et al, 2015;Komiya et al, 1999). Late extrusion is speculated to have exposed a cross section through the prism, such that peak metamorphic grade decreases from amphibolite to greenschist facies northeastward across the northeastern portion of the belt (Arai et al, 2015;Komiya et al, 1999). The main competing model argues that north-dipping subduction resulted in the ca.…”

Section: Researchmentioning

confidence: 99%

See 2 more Smart Citations

A non–plate tectonic model for the Eoarchean Isua supracrustal belt

et al. 2020

View full text Add to dashboard Cite

The ca. 3.8–3.6-b.y.-old Isua supracrustal belt of SW Greenland is Earth’s only site older than 3.2 Ga that is exclusively interpreted via plate-tectonic theory. The belt is divided into ca. 3.8 Ga and ca. 3.7 Ga halves, and these are interpreted as plate fragments that collided by ca. 3.6 Ga. However, such models are based on idiosyncratic interpretations of field observations and U-Pb zircon data, resulting in intricate, conflicting stratigraphic and structural interpretations. We reanalyzed published geochronological work and associated field constraints previously interpreted to show multiple plate-tectonic events and conducted field-based exploration of metamorphic and structural gradients previously interpreted to show heterogeneities recording plate-tectonic processes. Simpler interpretations are viable, i.e., the belt may have experienced nearly homogeneous metamorphic conditions and strain during a single deformation event prior to intrusion of ca. 3.5 Ga mafic dikes. Curtain and sheath folds occur at multiple scales throughout the belt, with the entire belt potentially representing Earth’s largest a-type fold. Integrating these findings, we present a new model in which two cycles of volcanic burial and resultant melting and tonalite-trondhjemite-granodiorite (TTG) intrusion produced first the ca. 3.8 Ga rocks and then the overlying ca. 3.7 Ga rocks, after which the whole belt was deformed and thinned in a shear zone, producing the multiscale a-type folding patterns. The Eoarchean assembly of the Isua supracrustal belt is therefore most simply explained by vertical stacking of volcanic and intrusive rocks followed by a single shearing event. In combination with well-preserved Paleoarchean terranes, these rocks record the waning downward advection of lithosphere inherent in volcanism-dominated heat-pipe tectonic models for early Earth. These interpretations are consistent with recent findings that early crust-mantle dynamics are remarkably similar across the solar system’s terrestrial bodies.

show abstract

Section: Introductionmentioning

confidence: 94%

Section: Geological Backgroundmentioning

confidence: 99%

Section: Researchmentioning

confidence: 99%

See 1 more Smart Citation

A non–plate tectonic model for the Eoarchean Isua supracrustal belt

et al. 2020

View full text Add to dashboard Cite

show abstract

“…The Isua supracrustal belt is comprised of at least five separate structural domains [55][56][57][58]; these were overprinted by one, two, or three metamorphic events in the Archean [59,60]. Other studies suggest polyphase metamorphism from greenschist to amphibolite facies, which divides the eastern part of the Isua belt into four zones having differing pressure and temperature conditions [61][62][63]. Furthermore, the Isua belt contains well-preserved cross-cutting intrusions, which formed during different episodes in the Archean and the Proterozoic [64,65].…”

Section: Geological Context and Research Materialsmentioning

confidence: 99%

“…Within one low-strain domain, primary volcanic and sedimentary features can still be found [20,56,66]. This area was probably influenced by only a single amphibolite facies metamorphism (450-475 • C and 360-400 MPa, at 3.69 Ga [59,60]) or by relatively low-grade greenschist metamorphism (360-400 • C and 150-400 MPa [63]). Therefore, samples collected from this area should provide the best available material for the study of Archean environmental conditions.…”

Section: Geological Context and Research Materialsmentioning

confidence: 99%

Chlorine Isotope Composition of Apatite from the >3.7 Ga Isua Supracrustal Belt, SW Greenland

et al. 2019

View full text Add to dashboard Cite

The study of the oldest surviving rock suites is crucial for understanding the processes that shaped the early Earth and formed an environment suitable for life. The metasedimentary and metavolcanic rocks of the early Archean Isua supracrustal belt contain abundant apatite, the geochemical signatures of which may help decipher ancient environmental conditions. However, previous research has shown that secondary processes, including amphibolite-facies metamorphism, have reset the original hydrogen isotope composition (δD) of apatite from the Isua belt; therefore, δD values are not indicative of primary conditions in the Archean. Here, we report the first in situ chlorine isotope (δ 37 Cl) analyses by Secondary Ion Mass Spectrometry (SIMS) from Isua apatite, which we combine with information from transmission electron microscopy, cathodoluminescence imaging, and spectroscopy, documenting the micron-scale internal features of apatite crystals. The determined δ 37 Cl SMOC values (chlorine isotope ratios vs. standard mean ocean chloride) fall within a range from −0.8% to 1.6% , with the most extreme values recorded by two banded iron formation samples. Our results show that δ 37 Cl values cannot uniquely document primary signatures of apatite crystals, but the results are nonetheless helpful for assessing the extent of secondary overprint.Minerals 2020, 10, 27 2 of 25 of evidence, such as putative microbial fabrics and carbon isotope signatures, arguing for traces of biological activity in the Isua rocks [6][7][8][9][10][11][12][13][14][15][16]. The recent study by Dodd et al. [17], in which variably 13 C-depleted graphitic carbon was identified in world-wide occurring banded iron formations, suggests Minerals 2020, 10, 27 21 of 25 materials by GS-IRMS. We would like to thank the editorial team and the reviewers for their suggestions and comments, which helped us to improve the quality of the manuscript. Conflicts of Interest:The authors declare no conflict of interest.

show abstract

Structural Architecture and Spatial-Temporal Distribution of the Archean Domains in the Eastern North China Craton

Peng

2016

Springer Geology

View full text Add to dashboard Cite

Intermediate P/T-type regional metamorphism of the Isua Supracrustal Belt, southern west Greenland: The oldest Pacific-type orogenic belt?

Cited by 22 publications

References 64 publications

A non–plate tectonic model for the Eoarchean Isua supracrustal belt

A non–plate tectonic model for the Eoarchean Isua supracrustal belt

Chlorine Isotope Composition of Apatite from the >3.7 Ga Isua Supracrustal Belt, SW Greenland

Structural Architecture and Spatial-Temporal Distribution of the Archean Domains in the Eastern North China Craton

Contact Info

Product

Resources

About