Wyniki wyszukiwania - BazTech

1

Klimat i oceanografia przełomu jury i kredy zachodniej Tetydy

Lodowski Damian Gerard

Przegląd Geologiczny

|

2023

|

Vol. 71, nr 10

514--522

EN

The key aspect for evaluation of potential effects of ongoing environmental changes is identification of their controlson one hand, and understanding of their mutual relations on other. In this context, the best source of information about medium and long term coThe key aspect for evaluation of potential effects of ongoing environmental changes is identification of their controlson one hand, and understanding of their mutual relations on other. In this context, the best source of information about medium and long term consequences of various environmental processes is the geologic record. Numerous different-scale palaeoenvironmental events took place during the Jurassic/Cretaceous transition; amongst them, the best documented so far are: long term marine regression during the Tithonian-early Berriasian, climate aridization during the late Tithonian-early Berriasian, and tectonic activity in western parts of the Neo Tethys Ocean during the late Berriasian-Valanginian. This study, which is based on the Ph Ddissertation of Damian Gerard Lodowski, attempts to reconstruct the latest Jurassic-earliest Cretaceous paleoenvironment and its evolution in the area of the Western Tethys, with special attention paid to cause-and-effect relationships between climate changes, tectonic activity and oceanographic conditions (perturbations in marine circulation and bioproductivity). Here are presented the basic results of high-resolution geochemical investigations performed in the Transdanubian Range (Hárskút and Lókút, Hungary), High-Tatric (Giewont, Poland) and Lower Sub-Tatric (Pośrednie III, Poland) series, Pieniny Klippen Belt (Brodno and Snežnica, Slovakia; Velykyi Kamianets, Ukraine) and Western Balkan (Barlya, Bulgaria) sections. The sections were correlated and compared in terms ofpaleoredox conditions (authigenic U), accumulation of micronutrient-type element (Zn) and climate changes (chemical index of alteration, CIA), providinga consistent scenario of the Tithonian-Berriasian palaeoenvironment evolution in various western Tethyan basins. Amongst the first-order trends and events, characteristic of studied sections are the two intervals recording an oxygen deficient at the seafloor: 1) the upper Tithonian-lowermost Berriasian (OD I); and 2) at the lower/upper Berriasian transition (OD II). Noteworthy, this phenomena cooccurred with elevated accumulations of nutrient-type elements (i. e. enrichment factor of Zn). Besides, collected data document the late Tithonian-early Berriasian trend of climate aridization, as well as the late Berriasian humidification. Such record is explained by a model, in which decreasing intensity of atmospheric circulation during the late Tithonian-early Berriasian was directly connected with climate cooling and aridization. This process resulted in lesser efficiency of up- and/or downwelling currents, which induced sea water stratification, seafloor hypoxia and perturbations in the nutrient-shuttle process during the OD I. On the other hand, the OD II interval may correspond to tectonic reactivation in the Neo Tethyan Collision Belt. This process might have led to physical cutoff of Alpine Tethys basins from the Neo Tethyan circulation (both atmospheric and oceanic), driving the limited stratification in the former, and limiting the effect of gradual humidification of global climate (i.e. due to increasing strength of monsoons and monsoonal upwellings). nsequences of various environmental processes is the geologic record. Numerous different-scale palaeoenvironmental events took place during the Jurassic/Cretaceous transition; amongst them, the best documented so far are: long term marine regression during the Tithonian-early Berriasian, climate aridization during the late Tithonian-early Berriasian, and tectonic activity in western parts of the Neo Tethys Ocean during the late Berriasian-Valanginian. This study, which is based on the Ph Ddissertation of Damian Gerard Lodowski, attempts to reconstruct the latest Jurassic-earliest Cretaceous paleoenvironment and its evolution in the area of the Western Tethys, with special attention paid to cause-and-effect relationships between climate changes, tectonic activity and oceanographic conditions (perturbations in marine circulation and bioproductivity). Here are presented the basic results of high-resolution geochemical investigations performed in the Transdanubian Range (Hárskút and Lókút, Hungary), High-Tatric (Giewont, Poland) and Lower Sub-Tatric (Pośrednie III, Poland) series, Pieniny Klippen Belt (Brodno and Snežnica, Slovakia; Velykyi Kamianets, Ukraine) and Western Balkan (Barlya, Bulgaria) sections. The sections were correlated and compared in terms ofpaleoredox conditions (authigenic U), accumulation of micronutrient-type element (Zn) and climate changes (chemical index of alteration, CIA), providinga consistent scenario of the Tithonian-Berriasian palaeoenvironment evolution in various western Tethyan basins. Amongst the first-order trends and events, characteristic of studied sections are the two intervals recording an oxygen deficient at the seafloor: 1) the upper Tithonian-lowermost Berriasian (OD I); and 2) at the lower/upper Berriasian transition (OD II). Noteworthy, this phenomena cooccurred with elevated accumulations of nutrient-type elements (i. e. enrichment factor of Zn). Besides, collected data document the late Tithonian-early Berriasian trend of climate aridization, as well as the late Berriasian humidification. Such record is explained by a model, in which decreasing intensity of atmospheric circulation during the late Tithonian-early Berriasian was directly connected with climate cooling and aridization. This process resulted in lesser efficiency of up- and/or downwelling currents, which induced sea water stratification, seafloor hypoxia and perturbations in the nutrient-shuttle process during the OD I. On the other hand, the OD II interval may correspond to tectonic reactivation in the Neo Tethyan Collision Belt. This process might have led to physical cutoff of Alpine Tethys basins from the Neo Tethyan circulation (both atmospheric and oceanic), driving the limited stratification in the former, and limiting the effect of gradual humidification of global climate (i.e. due to increasing strength of monsoons and monsoonal upwellings).

2

Oligocene crabs (Decapoda: Brachyura) from the Asmari Formation in Yasuj area (SW Iran)

Bahrami Ali, Ossó Alex, Yazdi Mehdi, Ansari Heshmatollah

Acta Geologica Polonica

|

2023

|

Vol. 73, no. 2

189--200

EN

New findings of crustacean decapod brachyurans from the Rupelian period (lower Oligocene) in Iran are presented in this study. In particular, Lophoranina sp. and Palaeocarpilius cf. P. rugifer Stoliczka, 1871, from the Rupelian strata were found in two previously unexplored localities, Abshar and Vezg near Yasuj in the southwestern region of Iran. The discovery contributes to fill the gap in the record of brachyuran decapod crustaceans in Iran during the Eocene and Miocene periods. The presence of both genera in the Oligocene of Iran suggests a certain degree of faunal similarity among brachyurans on both sides of the Tethys Realm.

3

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

Safari Amrollah, Ghanbarloo Hossein, Mansoury Parisa, Esfahani Mehran Mohammadian

Geologos

|

2020

|

Vol. 26, No. 2

93--111

EN

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.

4

Paleogeografia i tektonika płyt północnej Tetydy i Perytetydy w Polsce i na obszarach przyległych w jurze i wczesnej kredzie

Golonka J., Krobicki M., Matyszkiewicz J., Jędrzejowska-Tyczkowska H., Misiarz P., Olszewska B., Oszczypko N.

Nafta-Gaz

|

2005

|

R. 61, nr 7/8

314-320

PL

Jurajskie baseny północnej Tetydy powstały w wyniku rozpadu Pangei. W dolnej-środkowej jurze powstała Tetyda alpejska, podzielona przez wśródoceaniczny grzbiet czorsztyński na północnozachodni basen magurski, i południowowschodni basen pienińskiego pasa skałkowego. W późnej jurze rozwinął się ryft Karpat zewnętrznych (basen śląski) wypełniony górnojurajskimi-dolnokredowymi osadami fliszowymi. Grzbiet śląski oddzielał basen śląski od magurskiego. Na obszarze przedgórza Karpat mamy do czynienia z facjami Perytetydy reprezentowanymi przez osady węglanowe najwyższego doggeru - najniższego walanżyn. Można tu wyróżnić dwie megasekwencje: dolna zuni II, oraz dolna zuni III. Megasekwencja dolna zuni II rozpoczynałaby się transgresją w jurze środkowej a kończyłaby się regresją na przełomie kimeryd-tyton lub dolnym tytonie. Megasekwencja dolna zuni III zaczyna się cyklem transgresyjnym w dolnym tytonie a kończyłaby się generalną regresją w dolnym walanżynie. Na całym obszarze zapadliska występuje luka stratygraficzna pomiędzy kredą dolną i górną.

EN

Jurassic basins of the Northern Tethys originated during the Pangea break-up. During Early-Middle Jurassic Alpine Tethys was born. It was divided by middle-oceanic Czorsztyn Ridge into northwestern Magura Basin and southeastern Pieniny Klippen Belt Basin, The Outer Carpathian rift (Silesian Basin) developed during Late Jurassic. It was filled with the Upper Jurassic-Early Cretaceous flysch deposits. The Silesian ridge separated Silesian an Magura Basin. In the Carpathian foreland area Peri-Tethys facies were represented by uppermost Dogger - lowermost Valanginian carbonate deposits. Two megasequences could be distinguished here Lower Zuni II, began with the Middle Jurassic transgression and ended with Early Tithonian regression. Lower Zuni III lasted from Early Tithonian to the general Early Valanginian regression. There is a gap between Lower and Upper Cretaceous deposits in the whole Carpathian Foredeep area.