TY - JOUR
T1 - Sedimentary facies, mineralogy, and geochemistry of the sulphate-bearing Miocene Dam Formation in Qatar
AU - Dill, H. G.
AU - Botz, R.
AU - Berner, Z.
AU - Stüben, D.
AU - Nasir, S.
AU - Al-Saad, H.
N1 - Funding Information:
The senior author is grateful for the support provided by the College of Science, University of Qatar. Gratitude is especially expressed to the Scientific and Applied Research Centre (SARC) which was catering for the transport in the field. We are indebted to the staff members of the Qatar Centre of GIS who did not spare efforts in their assistance and provision with topographic data. Chemical analyses have been performed in the chemical labs of the Federal Institute for Geosciences and Natural Resources, Hannover, under the conductance of D. Rammlmair. The paper was reviewed by B. Sellwood, A.S.Alsharhan, and another anonymous reviewer. Their comments to the manuscript are acknowledged with thanks.
PY - 2005/1/18
Y1 - 2005/1/18
N2 - 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 siliciclastic-calcareous 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.
AB - 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 siliciclastic-calcareous 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.
KW - Deposition
KW - Evaporite
KW - Miocene
KW - Qatar
KW - Sabkha
KW - Siliciclastic-calcareous
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U2 - 10.1016/j.sedgeo.2004.11.004
DO - 10.1016/j.sedgeo.2004.11.004
M3 - Article
AN - SCOPUS:13244260770
SN - 0037-0738
VL - 174
SP - 63
EP - 96
JO - Sedimentary Geology
JF - Sedimentary Geology
IS - 1-2
ER -
