Abstract We use Pn -tomography to map lithospheric mantle velocity and anisotropy at the Arabia–Eurasia plate boundary, namely Makran and Zagros. We use catalogue events recorded by Oman, UAE, Saudi Arabia and Iran networks, the International Seismological Centre and the National Earthquake Information Center. Events of 1.8–16 degree distances were used for this Pn -tomography. In this study we show that the northeastern Arabia plate is characterized by cold and stable lithospheric mantle. Contrastingly, Eurasia is underlain by hot unstable lithospheric mantle. The Arabia–Eurasia lithospheric suture follows the Zagros collision surface suture within c. 70 km lateral proximity. At the southernmost Zagros collision, the Arabia lithosphere is inferred to extend further NE beneath Lut Block. This may be indicative of extended subduction of Arabia beneath Eurasia in southernmost Zagros. We find that eastern Makran shows typical subduction characteristics, with inferred oceanic lithosphere underlying the eastern Oman Sea and hot unstable lithospheric mantle below overriding Helmand Block. Contrastingly, the western Makran subduction zone including Arabia and Eurasia continental sides is underlain by a low- Pn -velocity anomaly, indicative of hot unstable lithospheric mantle. Surface evidence show that western, southern and eastern boundaries of western Makran low- Pn -velocity anomaly may represent a Late Neogene reactivated Precambrian terrane boundary in north Oman.

Abstract The actual state of knowledge concerning the tectonic evolution of the Afghan orogenic segment is summarized in the context of the neighbouring regions. The segment can be divided into: (1) the Late Palaeozoic North Afghan Variscan domain, which forms the southern margin of the Turan Plate; (2) the Early Cimmerian (Late Triassic–Early Jurassic) Palaeotethys suture zone of Middle Afghanistan, with the associated magmatic arc and back-arc rift extending from the Parapamisos and western Hindu Kush to the northern Pamir Mountains; (3) the Late Cimmerian (Late Jurassic–Early Cretaceous) domain of the Central Afghan Block mosaic with Gondwana-derived terranes; and (4) the Cenozoic-age Himalayan domain, which fringes the Cimmerian domain along the transpressive boundary of the Indian Plate in the east and the accretionary complex of the Makran subduction zone in the south. This current review of the scattered literature of a country where geological fieldwork effectively ceased 35 years ago is intended to bridge the gap between the better-known regions to the west in eastern Iran, and to the east in the Pamir–Punjab syntaxis.

Abstract In Lower Palaeozoic times, Gondwana was by far the largest tectonic entity, stretching from the South Pole to north of the Equator, and is termed a superterrane. We consider the northeastern sector of the Gondwanan and peri-Gondwanan margin, from Turkey through the Middle East, the north of the Indian subcontinent, southern China and SE Asia, to Australia and New Zealand. There was progressive tectonic activity along some of its margins during the period, with areas such as southeastern Australia undergoing enlargement through the accretion of island arcs as that part of Gondwana rotated. However, most of the area, from the Taurides of Turkey to at least east of India, represented a passive margin for the whole of the Lower Palaeozoic. Other adjacent areas, such as the Pontides of Turkey and Annamia (Indochina), were separate from the main Gondwanan craton as independent terranes. The quality and quantity of available data on Lower Palaeozoic rocks and faunas varies enormously over different parts of this substantial area, and there are few or no detailed palaeomagnetic data available for most of it. Some workers have considered the string of terranes from Armorica to the Malaysia Peninsula as having left Gondwana together in the late Cambrian as a Hun superterrane, leaving a widening Palaeotethys Ocean between it and Gondwana. However, we consider that the Palaeotethys opened no earlier than in late Silurian time (with Armorica and other terranes to its north), and that the Hun superterrane was not a cohesive unity. Other researchers vary in presenting many substantial Central Asian and Far Eastern terranes, including North China, South China, Tarim, Annamia and others, as integral parts of core Gondwana and not leaving it until Devonian and later times. We conclude that North China, Tarim and Annamia, among others, were probably not attached to core Gondwana in the Lower Palaeozoic, that South China was close to Gondwana (but not an integral part of it), and that Sibumasu was probably part of Gondwana. We try to reconcile the very varied published geological data and opinions, and present new palaeogeographical maps for that sector of Gondwana and surrounding areas for the Cambrian (500 Ma), Ordovician (480 Ma) and Silurian (425 Ma).

Abstract The South Caspian Basin was formed as a result of the interaction of the Eurasia, India, Arabia, and numerous microplates starting from the Trias-sic. During the Late Triassic–Early Jurassic, several microplates were sutured to the Eurasian margin, closing the Paleotethys Ocean. A Jurassic–Cretaceous north-dipping subduction was developed along this new continental margin south of the Pontides, Trans-Caucasus, and Iranian plates. This subduction zone trench-pulling effect caused rifting, creating the back-arc basin of the Greater Caucasus–proto-South Caspian Sea, which achieved a maximum width during the Late Cretaceous–early Paleogene. During the Eocene, the Lesser Caucasus, Sanandaj-Sirjan, and Makran plates were sutured to Trans-Caucasus–Talesh–South Caspian–Lut system. The subduc-tion zone jumped to the Scythian-Turan margin. The South Caspian underwent reorganization during the Oligocene–Neogene. Northward movement of the South Caspian microcontinent (SCM) resulted in rifting between SCM and Alborz plate. The southwestern part of the South Caspian Basin was reopened, whereas the northwestern part was gradually reduced in size. The source rocks of the Maikop Formation were deposited in the South Caspian Basin during the Oligocene–early Miocene. The collision of India and the Lut plate with Eurasia caused the deformation of Central Asia and created a system of northwest–southeast wrench faults. The remnants of the Jurassic–Cretaceous back-arc system oceanic and attenuated crust, as well as Tertiary oceanic and attenuated crust, were locked between adjacent continental plates and orogenic systems. Thick molasse-type sediments that accumulated during the Pliocene–Quaternary provided reservoir rocks and contributed to the burial and maturation of source rocks.

Abstract Thirty-two maps have been constructed which depict the plate-tectonic configuration, paleogeography, and selected lithofacies for Phanerozoic time intervals from the earliest Cambrian through the Neogene. The plate-tectonic maps illustrate geodynamic evolution of the Earth from the disassembly of Rodirua-Pannotia during Sauk time through closure, assembly, reorganization, and formation of the Pangean supercontinent during Tippecanoe, Kaskaskia, and Early Absaroka times, rifting, spreading, and disassembly during Late Absaroka and Zuni times, and new closure during Tejas time. The Earth's climate reflects the plate-tectonic phases of continental breakup and assembly. The climate changed from a greenhouse with short icehouse interlude through icehouse with warming interludes, and another greenhouse, to the present-day icehouse.