Comparative orotomy of the Archean Superior and Phanerozoic Altaid orogenic systems

Abstract

We compare and contrast the materials and mechanisms of continental crustal growth in the largest preserved regions of Phanerozoic and Archean juvenile additions to the crust, to test for similarities or differences in the formation of continents through time. We accomplish this through a comparison of map patterns, lithological contents, structural and metamorphic evolution, of the Phanerozoic Altaid orogenic system of Asia, with the Archean Superior Province of the North American Craton, in a method termed comparative orotomy. Both orogenic systems consist of collages of curvilinear belts of eroded arcs, some older continental slivers, and vast tracts of former subduction/accretionary complexes, containing numerous shreds of portions of the ophiolite suite, slivers of island and continental arcs, accreted oceanic plateaux, all intruded by multiple magmatic suites during or between multiple deformation events, then sliced by large transcurrent fault systems and bent into large oroclinal structures. We make this comparison because the Superior Province is a typical Archean craton that was later, in the Paleoproterozoic, incorporated into the larger North American craton, and has occupied a central position in several supercontinents (e.g., Kenorland, Nuna, which then formed the core of Columbia, Rodinia, Laurentia, and Pangea) during its longevity. Since it is the largest single fragment of Archean continental cratonic lithosphere preserved on Earth, the Superior Province is widely regarded as a testing ground about how Earth's continental crust was formed. Likewise, the Altaids encompass the largest region of crustal growth for the Phanerozoic. Our comparison with the Altaids is needed, as in recent years many myths about how the planet may have responded to higher heat production and flow in the Archean have emerged, because of trends in the science where the regional geology is ignored in favor of numerical models, isotopic proxies for assumed models of chemical behavior for crust-forming or tectonic processes, or comparisons with other-worldly bodies that bear little resemblance to our hydrous Earth. Thus, we return to the geological record, and here describe the map patterns, lithological associations, structural patterns, and evolution of both the Altaids and Superior Province, showing how comparative tectonics, orotomy, is useful in the absence of meaningful paleomagnetic or biostratigraphic data. We pay particular attention to the style of preservation of disaggregated members of the ophiolite suite (ophirags), their relationships with other tectonic units, and to the widespread but largely overlooked significance of late-stage major transcurrent motions and structural slicing of both Archean and Phanerozoic orogenic systems in defining the present-day architecture of both orogenic systems.

Voluminous continental growth of the Altaids and its control on metallogeny

“…The Altaids (Altaid tectonic collage [ 25–27 , 55 ], Central Asian Orogenic Supercollage [ 56 ], Central Asian Fold Belt [ 57 ], the Central Asian Orogenic Belt (CAOB; [ 28 , 29 , 30 ]) or the Phanerozoic Altaid orogenic systems [ 44 ]) is located between the Siberian, Baltic (the East European Cratons) and Tarim-North China cratons and occupies ∼8 745 000 km 2 [ 26 , 27 ]. The Altaids evolved from the late Precambrian (Ediacaran: 635 Ma) to the Early Cretaceous (∼145 Ma) [ 27 ].…”

“…Therefore, the Altaids is the most important site of Phanerozoic crustal growth and the largest preserved Phanerozoic juvenile crustal region. Kusky and Şengör [ 44 ] compared the map patterns, lithological contents, and structural and metamorphic evolution of the Altaids with those of the Archean Superior Province of the North American Craton to test for similarities or differences in the formation of continents through time. In addition, the comparison of crustal patterns and volumes of the two tectonic units is also significant.…”

“…Thus, the Altaids is considered to be Earth's largest Phanerozoic accretionary orogen and also the most important site of Phanerozoic crustal growth [ 25–29 , 31 , 42 , 43 ]. More recently, Kusky and Şengör [ 44 ] took the Altaids as the largest preserved Phanerozoic juvenile crustal region to compare it with the Archean Superior Province of the North American Craton to test for similarities or differences in the formation of continents through time and to confirm the onset time of accretionary orogenic systems and plate tectonics in the Archean Eon. On the other hand, the Altaids also comprises numerous ancient crustal blocks and microcontinents [ 45–49 ].…”

Altaids, continental growth and metallogeny

“…Safonova and Perfilova [ 9 ] reconstruct the survived and disappeared fossil intra-oceanic arcs in central and eastern Kazakhstan to manifest that accretionary growth and subduction erosion alternatively functioned at the active margins of the PAO in Paleozoic time. Using the powerful method of comparative orotomy, Kusky and Şengör [ 10 ] compare and contrast the comprehensive geological materials and mechanisms of the Archean Superior and Phanerozoic Altaid orogenic systems, revealing remarkable similarities in accretionary orogenic processes, spatial and temporal scales of structural progression, and formation of continents on Earth over time. Applying isotopic contour mapping, Wang et al .…”