Wyniki wyszukiwania - Biblioteka Nauki

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: Tethyan Seaway

Sortuj według:

Ogranicz wyniki do:

Sedimentary environment and depositional sequences of the Qom Basin (north-eastern margin of the Tethyan seaway)

100%

Binazadeh T. , Safari A. , Vaziri-Moghaddam H.

tom Vol. 94, No. 1

61--82

This research attempted to determine the depositional sequences of the Qom Formation in the Urumieh-Dokhtar arc (Ghamsar section) and Esfahan-Sirjan fore-arc (Abadeh section) sub-basins in Iran, using microfacies and microtaphofacies analyses. The authors also investigated connections between the Qom Basin and the Zagros and Paratethys basins during the Oligocene. In this regard a total of eight microfacies, two terrigenous facies, and five microtaphofacies were identified on the basis of 269 samples from the Ghamsar section and 93 samples from the Abadeh section. The studied microfacies, terrigenous facies, and microtaphofacies were deposited on a homoclinal carbonate ramp. This carbonate platform can be divided into inner, middle and outer ramp environments. On the basis of the distribution of microfacies and sequence stratigraphy studies, five third-order depositional sequences and one incomplete depositional sequence were identified in the Ghamsar section and three third-order depositional sequences in the Abadeh section. According to the distribution of microtaphofacies and palaeobathymetric studies based on Amphistegina, the energy, and depth of the Qom sea in the Ghamsar section were greater than those evidenced in the Abadeh section. The results of local fault activity in the different sub-basins of the studied sections indicate a lesser effect of global sea-level changes in the Paratethys basin. On the basis of the formation of depositional sequences in these sub-basins; and differences in the number of depositional sequences; intense local fault activity is indicated during the Chattian Age (especially in the Urumieh-Dokhtar arc sub-basin). Regional sea-level fluctuations of the south Tethyan Seaway and the Paratethys Basin controlled sea-level changes in the Chattian Age. The depositional basins of the Tethyan seaway (southern Tethyan seaway, Paratethys Basin and Qom Basin) probably were related during the Burdigalian to Langhian and the early Serravallian. The results show that, the effect of sea-level changes of the Zagros Sea on the formation of depositional sequences in the Esfahan-Sirjan fore-arc sub-basin was significant.

Reconstruction of the depositional sedimentary environment of Oligocene deposits (Qom Formation) in the Qom Basin (northern Tethyan seaway), Iran

72%

Safari A. , Ghanbarloo H. , Mansoury P. , Esfahani M. M.

2020

tom Vol. 26, No. 2

93--111

During the Rupelian–Chattian, the Qom Basin (northern seaway basin) was located between the Paratethys in the north and the southern Tethyan seaway in the south. The Oligocene deposits (Qom Formation) in the Qom Basin have been interpreted for a reconstruction of environmental conditions during deposition, as well as of the influence of local fault activities and global sea level changes expressed within the basin. We have also investigated connections between the Qom Basin and adjacent basins. Seven microfacies types have been distinguished in the former. These microfacies formed within three major depositional environments, i.e., restricted lagoon, open lagoon and open marine. Strata of the Qom Formation are suggested to have been formed in an open-shelf system. In addition, the deepening and shallowing patterns noted within the microfacies suggest the presence of three third-order sequences in the Bijegan area and two third-order depositional sequences and an incomplete depositional sequence in the Naragh area. Our analysis suggests that, during the Rupelian and Chattian stages, the depositional sequences of the Qom Basin were influenced primarily by local tectonics, while global sea level changes had a greater impact on the southern Tethyan seaway and Paratethys basins. The depositional basins of the Tethyan seaway (southern Tethyan seaway, Paratethys Basin and Qom Basin) were probably related during the Burdigalian to Langhian and early Serravallian.