Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen
The stratigraphic and palaeogeomorphologic conditions of the Qahlah Formation deposition in the U... more The stratigraphic and palaeogeomorphologic conditions of the Qahlah Formation deposition in the United Arab Emirates are related to the geotectonic evolution of the western Oman Mountains during the Late Cretaceous. The Qahlah Formation ranges from a few metres to more than 70 m in thickness. It is the first sedimentary deposit to onlap the abducted Semail ophiolite, which was subjected to extensive weathering in a tropical environment during the Maastrichtian. Erosion accompanied the transgression of the Maastrichtian sea across the region. The sedimentary sequence can be divided into four facies: ophiolitic breccia, ophiolitic conglomerate, lateritic ferruginous siltstone and lithic sandstone. These sediments were probably formed in a shallow-marine to beach setting adjacent to a retreating cliff line of the ophiolite. A comparative analysis of the principal chemical and mineralogical components of the different facies indicates a genetic relationship between them. The nickel content (0.85-l-1.16 wt%) in the laterite facies is of economic interest as a low-grade ore provided that larger reserves can be identified.
Nasir, S. and Sadeddin, W., 1989. The heavy minerals of the Kurnub Sandstone (Early Cretaceous) o... more Nasir, S. and Sadeddin, W., 1989. The heavy minerals of the Kurnub Sandstone (Early Cretaceous) of Jordan. Sediment. Geol. 62: 101-107. A study of the heavy-mineral distribution in the Kurnub Sandstone (Early Cretaceous) in Jordan was carried out in vertical and lateral sections. The heavy-mineral suites of the Kurnub Sandstone in north and south Jordan are identical and comparable to those in south Israel and southwest Sinai. The suites are mainly opaques, zircon, tourmaline and rutile; garnet, staurolite, epidot, anatase, barite and hornblende are less frequent. Staurolite and hornblende are confined to the south, whereas garnet is confined to a few horizons in the north. Selective chemical decomposition played a significant role in the modification of the unstable heavy-mineral variations in the Kurnub Sandstone. The ultrastable heavy minerals indicate a source area predominantly composed of granitic and metamorphic rocks. The association of zircon, tourmaline and rutile in a pure quartz arenite indicates that the main source of the Kurnub Sandstone of Jordan must be weathered Paleozoic sediments.
The Miocene deposits of the Dam Formation were deposited in a narrow seaway stretching along the ... more The Miocene deposits of the Dam Formation were deposited in a narrow seaway stretching along the western edge of the Qatar Arch. During the initial stages of basin evolution the rising Zagros Mts. delivered debris in this fore deep basin. The paleocurrent and paleogeographic zonation are reflected by the heavy mineral assemblage, by the spatial distribution of phyllosilicates and the various types of sulphate. From NW towards the SE, the contents of smectite and palygorskite increase, whereas the illite and kaolinite contents decrease. Mega crystals of gypsum are found in the NW and massive fine-grained gypsum in the SE of the basin. During the waning stages of basin subsidence, the Arabian Shield became more and more important as a source for the Miocene sediments. In this study, the Dam Formation was subdivided into 7 members/lithofacies associations (lower, middle, upper Salwa, and Al Nakhsh Members, Abu Samrah Member). The Salwa Members at the base of the Dam Formation consists of heterolithic siliciclasticcalcareous sediments which were laid down under meso-to microtidal conditions. The Al Nakhsh Members formed under macrotidal conditions with sub-to supratidal depositional environments passing into continental ones. Celestite, gypsum, and microbial mats (stromatolites) are very widespread in these sabkha sediments. Crystals of gypsum and the thickness of stromatolites tremendously increase towards younger sediments indicating thereby a close genetic link between growth of microbial domes and gypsum precipitation. Throughout the Abu Samrah Member marine calcareous sediments were deposited in a microtidal wave-dominated environment. Dissolution of Eocene evaporites at depth governed the lithofacies differentiation in the Miocene Dam Formation.
A new fossiliferous locality is discovered from the upper Eocene Aydim Formation, in Dhofar, Sout... more A new fossiliferous locality is discovered from the upper Eocene Aydim Formation, in Dhofar, Southern Sultanate of Oman. A left ulna of Arsinoitherium is described, and cranial and postcranial specimens found in close proximity are referred to the same taxon. The locality is promising for the recovery of additional fossil specimens. Moreover, the presence of Arsinoitherium in Oman is of biogeographic significance; as the Red Sea did not exist during the late Eocene, these large-bodied animals were able to freely travel between what is now the Arabian Peninsula and continental Africa.
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen
The stratigraphic and palaeogeomorphologic conditions of the Qahlah Formation deposition in the U... more The stratigraphic and palaeogeomorphologic conditions of the Qahlah Formation deposition in the United Arab Emirates are related to the geotectonic evolution of the western Oman Mountains during the Late Cretaceous. The Qahlah Formation ranges from a few metres to more than 70 m in thickness. It is the first sedimentary deposit to onlap the abducted Semail ophiolite, which was subjected to extensive weathering in a tropical environment during the Maastrichtian. Erosion accompanied the transgression of the Maastrichtian sea across the region. The sedimentary sequence can be divided into four facies: ophiolitic breccia, ophiolitic conglomerate, lateritic ferruginous siltstone and lithic sandstone. These sediments were probably formed in a shallow-marine to beach setting adjacent to a retreating cliff line of the ophiolite. A comparative analysis of the principal chemical and mineralogical components of the different facies indicates a genetic relationship between them. The nickel content (0.85-l-1.16 wt%) in the laterite facies is of economic interest as a low-grade ore provided that larger reserves can be identified.
Nasir, S. and Sadeddin, W., 1989. The heavy minerals of the Kurnub Sandstone (Early Cretaceous) o... more Nasir, S. and Sadeddin, W., 1989. The heavy minerals of the Kurnub Sandstone (Early Cretaceous) of Jordan. Sediment. Geol. 62: 101-107. A study of the heavy-mineral distribution in the Kurnub Sandstone (Early Cretaceous) in Jordan was carried out in vertical and lateral sections. The heavy-mineral suites of the Kurnub Sandstone in north and south Jordan are identical and comparable to those in south Israel and southwest Sinai. The suites are mainly opaques, zircon, tourmaline and rutile; garnet, staurolite, epidot, anatase, barite and hornblende are less frequent. Staurolite and hornblende are confined to the south, whereas garnet is confined to a few horizons in the north. Selective chemical decomposition played a significant role in the modification of the unstable heavy-mineral variations in the Kurnub Sandstone. The ultrastable heavy minerals indicate a source area predominantly composed of granitic and metamorphic rocks. The association of zircon, tourmaline and rutile in a pure quartz arenite indicates that the main source of the Kurnub Sandstone of Jordan must be weathered Paleozoic sediments.
The Miocene deposits of the Dam Formation were deposited in a narrow seaway stretching along the ... more The Miocene deposits of the Dam Formation were deposited in a narrow seaway stretching along the western edge of the Qatar Arch. During the initial stages of basin evolution the rising Zagros Mts. delivered debris in this fore deep basin. The paleocurrent and paleogeographic zonation are reflected by the heavy mineral assemblage, by the spatial distribution of phyllosilicates and the various types of sulphate. From NW towards the SE, the contents of smectite and palygorskite increase, whereas the illite and kaolinite contents decrease. Mega crystals of gypsum are found in the NW and massive fine-grained gypsum in the SE of the basin. During the waning stages of basin subsidence, the Arabian Shield became more and more important as a source for the Miocene sediments. In this study, the Dam Formation was subdivided into 7 members/lithofacies associations (lower, middle, upper Salwa, and Al Nakhsh Members, Abu Samrah Member). The Salwa Members at the base of the Dam Formation consists of heterolithic siliciclasticcalcareous sediments which were laid down under meso-to microtidal conditions. The Al Nakhsh Members formed under macrotidal conditions with sub-to supratidal depositional environments passing into continental ones. Celestite, gypsum, and microbial mats (stromatolites) are very widespread in these sabkha sediments. Crystals of gypsum and the thickness of stromatolites tremendously increase towards younger sediments indicating thereby a close genetic link between growth of microbial domes and gypsum precipitation. Throughout the Abu Samrah Member marine calcareous sediments were deposited in a microtidal wave-dominated environment. Dissolution of Eocene evaporites at depth governed the lithofacies differentiation in the Miocene Dam Formation.
A new fossiliferous locality is discovered from the upper Eocene Aydim Formation, in Dhofar, Sout... more A new fossiliferous locality is discovered from the upper Eocene Aydim Formation, in Dhofar, Southern Sultanate of Oman. A left ulna of Arsinoitherium is described, and cranial and postcranial specimens found in close proximity are referred to the same taxon. The locality is promising for the recovery of additional fossil specimens. Moreover, the presence of Arsinoitherium in Oman is of biogeographic significance; as the Red Sea did not exist during the late Eocene, these large-bodied animals were able to freely travel between what is now the Arabian Peninsula and continental Africa.
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