The Itmurundy Pacific-type orogenic belt in northern Balkhash, central Kazakhstan: Revisited plus first U–Pb age, geochemical and Nd isotope data from igneous rocks

Safonova, Inna; Savinskiy, Ilya; Perfilova, Alina; Gurova, A. V.; Maruyama, S.; Tsujimori, Tatsuki

doi:10.1016/j.gr.2019.09.004

Cited by 31 publications

(17 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The thickness of the Tekturmas chert is estimated as at least 200 m (Figure ), that is, notably larger than that in other regions of central Kazakhstan (Gridina, ; Popov & Tolmacheva, ), but comparable with that of Itmurundy cherty formations outcropped in northern Balkhash (Safonova et al, ; Safonova, Savinskiy, Perfilova, Gurova, & Maruyama, ). Such a thickness, even if overestimated due to the coupling/thrusting of tectonic sheets, suggests a large oceanic realm as also was shown in the Itmurundy accretionary complex (Safonova et al, ).…”

Section: Discussionmentioning

confidence: 88%

The Tekturmas ophiolite belt of central Kazakhstan: Geology, magmatism, and tectonics

et al. 2020

View full text Add to dashboard Cite

The Tekturmas ophiolite belt of central Kazakhstan is located in the western Central Asian Orogenic Belt. It consists of three structural‐formational zones: Tekturmas (centre), Bazarbai (north), and Sarysui (south). The Tekturmas zone includes igneous and sedimentary rocks of Karamurun, Tekturmas, and Sarytau formations, which are dominated by volcanogenic, deep sea, and clastic deposits, respectively. The Bazarbai zone consists of Kuzek and Basarbai formations dominated, respectively, by basaltic and sedimentary rocks. The Sarysui zone includes terrigenous Airtau and olistostromic Ermek formations. The age of sedimentary rocks was constrained by microfossils. The igneous rocks of the Karamurun and Bazarbai formations are alkaline and subalkaline basalt/dolerite, andesibasalt, and andesite. There are three main groups of rocks: high‐Ti, mid‐Ti, and low‐Ti. The high‐Ti Karamurun volcanics and low‐Ti Bazarbai are variably enriched in light rare earth element (LREE) showing LREE enriched (high‐Ti) and LREE flat (low‐Ti) REE patterns. The high‐Ti group shows enrichment in Nb, Th, Zr, and Sm compared with the low‐Ti group. The low‐Ti group is special for the Nb troughs in primitive mantle‐normalized multi‐element diagrams, which are typical of supra‐subduction settings. Both groups yielded positive εNd values, although the averages are 4.6 and 7.5 for the high‐ and low‐Ti rocks, respectively. The geochemical features suggest formation of the igneous rocks in oceanic and supra‐subduction (intra‐oceanic arc) settings. The geological and geochemical features of the Tekturmas ophiolite belt accord well with the tectonic emplacement of ophiolites and formation of accretionary complex at a Pacific‐type convergent margin similar to those of the western Pacific.

show abstract

Section: Discussionmentioning

confidence: 88%

The Tekturmas ophiolite belt of central Kazakhstan: Geology, magmatism, and tectonics

et al. 2020

View full text Add to dashboard Cite

show abstract

“…It is characterized by a horseshoe‐shaped oroclinal structure, extending from the northern limb of Chingiz arc to the southern limb of Yili arc (Figure 1b) (Şengör et al, 1993; Xiao et al, 2010). Paleomagnetic and geological studies revealed that several independent and short‐lived arc systems were amalgamated and/or welded together to form a long, quasi‐rectilinear ribbon continent in the latest Ordovician to Middle Silurian (e.g., Khassen et al, 2020; Korobkin & Buslov, 2011; Safonova et al, 2019, 2020). In the Late Silurian, this ribbon continent moved northward, crossed the equator and rotated clockwise by ~45° to a NW‐SE orientation (Figure 1c).…”

Section: Discussionmentioning

confidence: 99%

“…The Precambrian microcontinents include Ishim-Middle Tianshan, Kokchetav-North Tianshan, Aktau-Junggar, and Chu-Yili ( Figure 1b) (Wilhem et al, 2012;Windley et al, 2007). The continental/island arcs are represented by Boshchekul-Chingiz arc, Baydaulet-Akbastau arc, Selety-Urumbar arc, Balkhash-Yili arc, Itmurundy-Tekturmas arc, and Early to Middle Devonian volcanic belt ( Figure 1b) (e.g., Khassen et al, 2020;Safonova et al, 2017Safonova et al, , 2019Safonova et al, , 2020. The accretionary wedges occur as Chinese North Tianshan belt, West Junggar, Balkhash, and Erementau ( Figure 1b).…”

Section: Geological Backgroundmentioning

confidence: 99%

“…The Kazakhstan Orocline can be divided into the northern limb (the Chingiz arc), the hinge (the Kokchetav‐North Tianshan), and the southern limb (the Yili arc) (Figure 1b). The northern limb mainly consists of several island arcs (e.g., Boshchekul‐Chingiz and Zharma‐Saur) and some accretionary wedges (e.g., West Junggar and Balkhash) (Figure 1b) (Degtyarev, 2011; Safonova et al, 2020; Shen et al, 2015), while the hinge is primarily composed of Ishim‐Middle Tianshan, Kokchetav‐North Tianshan Precambrian microcontinents (e.g., Erementau and Zhaman‐Sarysu) (Figure 1b) (Bazhenov et al, 2012; Degtyarev et al, 2017; Seltmann et al, 2011). The southern limb was built on several microcontinents (e.g., Aktau‐Junggar and Chu‐Yili) juxtaposed to Paleozoic accretionary wedges (e.g., Chinese North Tianshan belt and South Tianshan belt, STB) (Figure 1b) (Xiao et al, 2015).…”

Section: Geological Backgroundmentioning

confidence: 99%

“…The western part of CAOB is occupied by the Kazakhstan collage system, which is characterized by oroclinal bending and mainly made up of the Chingiz, Baydaulet-Akbastau, Kokchetav-North Tianshan, Ishim-Middle Tianshan, Aktau-Junggar, and Chu-Yili terranes ( Figure 1b) (Levashova et al, 2012;Seltmann et al, 2014). These terranes dispersed independently in the western PAO before Ordovician and amalgamated together in the Latest Ordovician to Middle Silurian, forming a long EW-striking ribbon continent (Khassen et al, 2020;Korobkin & Buslov, 2011;Safonova et al, 2019Safonova et al, , 2020. In the Late Silurian, the ribbon continent began to move northward and rotated clockwise to NW direction ( Figure 1c).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Evolution of Late Paleozoic Magmatic Arc in the Yili Block, NW China: Implications for Oroclinal Bending in the Western Central Asian Orogenic Belt

et al. 2020

View full text Add to dashboard Cite

Subduction transformation (advancing vs. retreating) may be manifested by compositional variations of arc magmas and may result in oroclinal bending. Identifying relevant chemical and physical processes is crucial for understanding accretionary orogenesis and continental crustal evolution. The Northern Yili Block (NYB) was situated on an active margin associated with subduction of the Junggar Ocean (part of the Paleo-Asian Ocean) and underwent perplexing accretionary orogenesis in late Paleozoic. Two episodes of subduction-related granitoid magmatism have been identified, the first in the Late Devonian (374-369 Ma) and the second in the Late Carboniferous (ca. 304 Ma). These two episodes of granitoid magmatism exhibit contrasting features; for example, the first episode shows low ε Nd (t) (−6 to −2) and ε Hf (t) (−12 to +3) values, while the second episode displays relatively higher values (−2 to +7 and 0 to +20, respectively), suggesting increase contribution of juvenile components in the magma sources. The calculated zircon saturation temperatures are mostly <800°C for the first episode but increased to >800°C for the second episode. The (La/Yb) N ratios of the two-episode granitoids vary from 2-17 to 1-9, indicative of the NYB crustal thinning in the Late Carboniferous. In addition, the migrations of the magmatic arc and trench in the NYB took place coevally in the Late Carboniferous and were accompanied by development of an accretionary complex and an immature back-arc basin. We interpret that the arc magmatic variations and migrations reflect geodynamic transition from the Late Devonian advancing subduction to the Late Carboniferous retreating subduction. The retreating subduction of the Junggar oceanic plate possibly resulted in prominent oroclinal bending of the southern Kazakhstan collage system in the Late Carboniferous.

show abstract

Ediacaran‐Cambrian intra‐oceanic arc volcanic rocks in southern West Junggar, NW China: New constraints on the initial subduction of the Junggar‐Balkhash Ocean and migration of arc magmatism

Liao

Han

et al. 2021

Geological Journal

View full text Add to dashboard Cite

As numerous blocks of the Ediacaran‐Cambrian supra‐subduction zone ophiolites, seamounts, subduction‐related metamorphic rocks, and arc granitoids have been identified in the ophiolitic mélanges in the contiguous West Junggar (China) and Balkhash (Kazakhstan) area, the initial subduction of the Junggar‐Balkhash Ocean, a major branch of the southern Palaeo‐Asian Ocean is emerging as an interesting topic. In this study, we present new data from diabase and basalt xenoliths in an Ediacaran‐Early Cambrian quartz‐monzonite block within the Tangbale ophiolitic mélange and an isolated dacitic tufflava block within the Saleinuohai ophiolitic mélange in southern West Junggar, NW China, as another line of evidence for the Ediacaran initial subduction of the Junggar‐Balkhash Ocean and the Cambrian migration of arc magmatism in West Junggar. The diabase and dacitic tufflava yield concordant zircon U–Pb ages of 568 and 530 Ma, respectively. The diabase and basalt exhibit high Al2O3 (17.38–17.75 wt%) and low TiO2 (0.69–0.90 wt%), with Mg# = 47–55, whereas the dacitic tufflava is characterized by high Na2O (7.87–8.43 wt%), with Mg# = 46–49. All the samples display similar LREE and large‐ion lithophile element (LILE) enrichment and Nb, Ta, Ti, and varying Zr and Hf depletion, indicating that they were formed in an intra‐oceanic arc setting. An integration of the new and published data shows that the subduction of the Junggar‐Balkhash Ocean was initiated in the Late Ediacaran at least, followed by slab rollback and retreat of subduction zone, which would be responsible for the northward migration of arc magmatism.

show abstract

The Itmurundy Pacific-type orogenic belt in northern Balkhash, central Kazakhstan: Revisited plus first U–Pb age, geochemical and Nd isotope data from igneous rocks

Cited by 31 publications

References 38 publications

The Tekturmas ophiolite belt of central Kazakhstan: Geology, magmatism, and tectonics

The Tekturmas ophiolite belt of central Kazakhstan: Geology, magmatism, and tectonics

Evolution of Late Paleozoic Magmatic Arc in the Yili Block, NW China: Implications for Oroclinal Bending in the Western Central Asian Orogenic Belt

Ediacaran‐Cambrian intra‐oceanic arc volcanic rocks in southern West Junggar, NW China: New constraints on the initial subduction of the Junggar‐Balkhash Ocean and migration of arc magmatism

Contact Info

Product

Resources

About