Suturing of the Proto- and Paleo-Tethys oceans in the western Kunlun Xinjiang, China
F. Mattern
a,
, W. Schneider
b
a
Institut fu¨r Geologı¨e, Geophysik und Geoinformatik, Freie Universita¨t Berlin, Matteserstraße 74-100, D-12249 Berlin, Germany
b
Institut fu¨r Geowissenschaften, Technische Universita¨t Braunschweig, Pockelsstraße 4, D-38106, Braunschweig, Germany Received 5 February 1999; accepted 30 September 1999
Abstract
The Proto-Tethys Ocean between the North and South Kunlun began to form during the Sinian. Remnants of this ocean are preserved at the Oytag-Kudi suture. The presence of Paleozoic arc batholiths in the northern South Kunlun and their absence in the North Kunlun indicates
southward subduction of the Proto-Tethys Ocean beneath the South Kunlun. Opposite subduction polarity can be demonstrated for the Late Paleozoic to mid-Mesozoic when the southerly located Paleo-Tethys Ocean was consumed beneath the South Kunlun and generated a Late
Carboniferous to mid-Jurassic magmatic arc in the southern South Kunlun. Arc magmatism affected the southern South Kunlun and the large Kara-Kunlun accretionary prism a suture sensu lato which formed as a result of Paleo-Tethys’ consumption. The dextral shear sense of
ductile faults which are located at the margins of the arc batholiths, and which parallel the South KunlunKara-Kunlun boundary, suggests oblique plate convergence with a dextral component. Different lines of evidence encourage us to interpret the Proto-Tethys ophiolites of the
Oytag-Kudi zone as at least partly derived from an oceanic back-arc basin. In contrast, we assume that Paleo-Tethys was a large ocean basin which was eliminated directly at the southern margin of the South Kunlun where no oceanic back-arc region existed. q 2000 Elsevier
Science Ltd. All rights reserved.
1. Introduction
Knowledge of the geology of the Kunlun was always sparse, as it is difficult to access this geographic frontier.
Until recently, fundamental geological knowledge of the western Kunlun remained obscure to the international geos-
cientific community because since 1949 foreigners were not allowed to visit the area Gaetani et al., 1990. Only as of
1988 could non-Chinese workers carry out investigations in the region again. The Italian expedition team was the first
one to resume foreign research efforts Gaetani et al., 1990. On the basis of recently collected data by Chinese and other
workers e.g. Liu et al., 1988; Gaetani et al., 1990, 1991; Matte et al., 1991; 1996; Pan et al., 1992; Yao and Hsu¨,
1994; Mattern et al., 1996, it is now possible to review the main aspects of the geology of the western Kunlun. Our
descriptions pay special attention to those aspects signifi- cant for the reconstruction of the geodynamic development.
For more details on the regional geology the reader is referred to the quoted literature and the sources therein.
Our main intention is to decipher the pre-Cenozoic plate tectonic processes which shaped the western Kunlun.
Subduction of oceanic lithosphere plays a key role in this regard. At the same time we will also address problematic
aspects in the understanding of the tectonic history.
The western Kunlun is one of the Earth’s highest moun- tain ranges. It is located south of the Tarim Basin Takla
Makan Desert and north of the westernmost part of the Tibet Plateau which is referred to as the “Kara-Kunlun”
area Fig. 1. To the northwest, parts of the Kunlun are morphologically and geologically transitional to the Pamirs.
The western Kunlun represents an accretion zone at which Central Asia grew during the Phanerozoic. It is tectonostra-
tigraphically subdivided into the North Kunlun, i.e. the southern margin of the Tarim Block, and the narrow
South Kunlun, which was the site of two Phanerozoic magmatic arc-related intrusion cycles. Both tectonic units
are separated by the ophiolite-bearing Oytag-Kudi suture Fig. 1. The Kara-Kunlun is a sizeable mid-Phanerozoic
accretionary wedge.
We use the geological time table by Haq and van Eysinga 1987 in correlating radiometric ages with geological time
units and corresponding stratigraphical time–rock units and in assigning numerical time spans.
Journal of Asian Earth Sciences 18 2000 637–650
1367-912000 - see front matter q 2000 Elsevier Science Ltd. All rights reserved. PII: S 1 3 6 7 - 9 1 2 0 0 0 0 0 0 1 1 - 0
www.elsevier.nllocatejseaes
Corresponding author. E-mail address: frankcapecod.net F. Mattern.
2. Sinian rifting of the North Kunlun and creation of the Proto-Tethys Ocean
