Page 4 - i1052-5173-32-1

Discovery of an Entrapped Early Permian

(ca. 299 Ma) Peri-Gondwanic Sliver in the

Cretaceous Shyok Suture of Northern

Ladakh, India: Diverse Implications

Rajeev Upadhyay, Dept. of Geology (CAS), Kumaun University, Nainital-263001 (Uttarakhand), India, rajeevntl1@gmail.com; Saurabh
Gautam, Birbal Sahni Institute of Palaeosciences, 53 University Road, Lucknow-226007, India; and Ram Awatar, 7/464 A, Vikas Nagar,
Lucknow-226022, India

ABSTRACT spreading, which produced new oceanic et al., 1990; Scotese and McKerrow, 1990;
In a significant breakthrough, we report crust and several smaller oceans and larger Scotese and Langford, 1995; Upadhyay et
the first discovery of twenty-six genera plates. The erstwhile Tethys Ocean, juxta- al., 1999b; Muttoni et al., 2009). These
and thirty-five species of Early Permian posed between the Eurasian continent in the blocks belong to a poorly defined continent
(Asselian–Sakmarian and Artinskian; 299 north and Gondwana in the south, ruptured, named peri-Gondwana or Cimmeria (Şengör,
Ma to 276 Ma) Gondwanic palynomorphs and culminated into the subsequent open- 1987). Based on the occurrence of Early
from a tectonically emplaced metasedimen- ing and closing of nascent Neo-Tethys and Permian marine Gondwanan sediments,
tary sliver of Shyok Ophiolitic Mélange of Paleo-Tethys oceans, respectively. Several the Karakoram terrane is now (Fig. 1) iden-
the India-Asia Collision zone of Northern smaller continental fragments existed tified as a peri-Gondwanan microcontinent
Ladakh, India. These palynofloral assem- between the two continental masses (Smith at a latitude ~35 S, somewhere between the
blages are of peri-Gondwanian (Cimmerian) et al., 1981; Nie et al., 1990; Scotese and Indian plate and the Qiangtang-Lhasa blocks
origin and have a strong affinity with the Langford, 1995; Upadhyay et al., 1999b). (Upadhyay et al., 1999b). Paleogeographic
Gondwana assemblage of peninsular India. Paleogeographic reconstructions of reconstruction of the Early Permian shows
Similar palynofloral assemblages are also Pangaea during the late Paleozoic (Smith et that these peri-Gondwanian microconti-
known from Extra-Peninsular India, Salt al., 1981; Nie et al., 1990; Scotese and nents were situated between ~20° and 40°
Range, Karakoram, Antarctica, Australia, Langford, 1995) show that a southern belt of southern latitudes (Nie et al., 1990; Scotese
South Africa, and South America. The these continental fragments stretching from and Langford, 1995; Muttoni et al., 2009).
occurrence of Gondwanic sliver within the Iran and Afghanistan, through Tibet to Thus, the origin and evolution of the
Shyok Suture is interpreted as a thin flake western Thailand, Malaysia, and Sumatra Ladakh-Kohistan block and Karakoram ter-
of active continental margin of peri- has been accreted to Asia since the mid- rane of northwest India and Lhasa and
Gondwanic microcontinent/Kshiroda plate, Paleozoic (Şengör, 1987; Metcalfe, 2006). Qiangtang blocks of western Tibet have now
which was sliced off during the subduction/ The Karakoram-Hindukush microplate in been widely accepted to have resulted
collision process, between Ladakh block the west and the Qiangtang-Lhasa block in from multiple subduction/collisional events
and Karakoram–Qiangtang-Lhasa terrane central and southeastern Asia are among between Gondwana-derived terranes or con-
and amalgamated with obducted remnants these blocks, which were welded/sutured to tinents and Eurasia since the late Paleozoic
of the accretionary prism of the nascent Asia, probably around 130–120 Ma (Şengör, (Gansser, 1977; Allégre et al., 1984; Şengör,
Shyok Suture. The Shyok Suture closed 1987; Dewey et al., 1988, and references 1987; Dewey et al., 1988; Scotese and
during the mid- to Late Cretaceous period. therein) (Fig. 1). The origin, migration path, McKerrow, 1990; Nie et al., 1990; Beck et al.,
Subsequent syn- and post-collision syn- timing of accretion, and assembly of all of 1995; Burg et al., 1996; Upadhyay et al.,
kinematic episodes tectonically juxtaposed these blocks in their present tectonic posi- 1999b; Metcalfe, 2006; Muttoni et al., 2009;
the peri-Gondwanic sliver in the tectonized tion are little known. The paleogeography Bouilhol et al., 2013; Upadhyay, 2002, 2014;
zone of Shyok Ophiolitic Mélange. The during the break-up of Gondwana is poorly Borneman et al., 2015).
India-Asia collision, which took place ca. constrained, and scant geological informa- In northwest India, the Ladakh block lies
60–50 Ma with the demise of Neo-Tethys tion is available from Pamir, Northern between the Indian Plate in the south and
Ocean, along the Indus Tsangpo Suture Ladakh, Karakoram, and western Tibet. the Eurasian Plate in the north. To the west,
Zone, modified the geometry of accreted However, based on temperate fauna, flora, this block is separated from the Kohistan
ophiolitic stack of the Shyok Suture. and even glacial and glaciomarine deposits Complex by the Nanga Parbat–Haramosh
(tillites or diamictites) from the Permian syntaxis, and to the east, it is separated
INTRODUCTION sequences, the Central Iran, Helmand, from the Lhasa and Quiangtang blocks by
The supercontinent Pangaea began to Western Qiangtang, Lhasa, and Sibumasu the Karakoram fault (Upadhyay, 2002,
break apart during the late Carboniferous– blocks are interpreted as having rifted off 2014) (Figs. 1 and 2). The Ladakh block is
early Permian period (ca. 300 Ma–272 Ma). the northern margin of Gondwana in post- bounded by two suture zones—the Indus
This break-up is followed by the seafloor Early Permian times (Smith et al., 1981; Nie Suture in the south and the Shyok Suture in

GSA Today, v. 32, https://doi.org/10.1130/GSATG481A.1. CC-BY-NC.

4 GSA TODAY | January 2022