Ograniczanie wyników
Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 84

Liczba wyników na stronie
first rewind previous Strona / 5 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  Upper Jurassic
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 5 next fast forward last
PL
W artykule zaprezentowano wyniki analizy sejsmicznej i otworowej dla utworów jury górnej z rejonu usytuowanego na południe i południowy wschód od Tarnowa, której celem było określenie potencjału geotermalnego tego obszaru. Przeprowadzona analiza geologiczno-złożowa wykazała, że skały węglanowe górnej jury są dobrym kolektorem wód geotermalnych, a najbardziej perspektywiczne do uzyskania większych wydajności są strefy uskokowo-szczelinowe oraz strefy pogrążonego paleokrasu. Świadczą o tym opróbowania przeprowadzone w otworach wiertniczych w interwale skał górnojurajskich, które wykazały przypływy wód termalnych o wydajnościach do 30 m3 /h i temperaturze rzędu 50–80°C. Duża część z tych opróbowań związana jest bądź to ze strefami spękań i uskoków, bądź też z przypowierzchniową strefą rozwoju paleokrasu. Wspomniane utwory górnej jury zalegają w obszarze badań na głębokości od 1600 m do ponad 3000 m p.p.m. W ich nadkładzie występują węglanowe utwory kredy górnej, klastyczne utwory miocenu (autochtonicznego i jednostki zgłobickiej) oraz utwory jednostek tektonicznych Karpat. Zakres przeprowadzonych badań pozwolił na rozpoznanie budowy geologicznej oraz warunków złożowych analizowanego rejonu. Było to podstawą do wytypowania obszaru perspektywicznego, zlokalizowanego we wschodniej części obszaru badań, w obrębie którego można spodziewać się wyższych temperatur oraz możliwości uzyskania większych wydajności wód termalnych, koniecznych do zasilania obiektów energetycznych, ciepłowniczych czy też rekreacyjnych. W rejonie tym na podstawie danych sejsmicznych wyinterpretowano obecność skomplikowanego systemu uskoków, w większości o przebiegu z NW na SE. Dla wytypowanego obszaru perspektywicznego przedstawiono szczegółową charakterystykę parametrów złożowych, istotnych w kontekście poszukiwania i eksploatacji wód geotermalnych.
EN
The article presents the results of a seismic and well analysis conducted for the Upper Jurassic formations in the area south and southeast of Tarnów, aimed at determining the geothermal potential of this area. A geological and reservoir analysis has shown that the Upper Jurassic carbonate rocks are a good collector of geothermal water, and the fault and fracture zones as well as the buried paleokarst zones are the most promising for higher yields. Tests conducted in wells in the interval of the Upper Jurassic rocks, showed thermal water flows of up to 30 m3 /h and temperatures in the range of 50–80°C. A large number of these tests are either associated with zones of faults and fractures, or with the near-surface paleokarst zone. These Upper Jurassic sediments occure in the study area at depths ranging from 1600 meters to more than 3000 meters below sea level. In their overburden are carbonate formations of the Upper Cretaceous, clastic sediments of the Miocene (autochthonous and the Zgłobice Unit) and formations of the tectonic units of the Carpathians. The scope of the study helped determine the geological structure and reservoir conditions of the analyzed region. This was fundamental to the selection of a prospective area, located in the eastern part of the study area, within which higher temperatures and the possibility of higher thermal water yields, necessary for power, heating or recreational facilities, can be expected. In this area, the presence of a complex fault system, mostly running NW-SE, was interpreted from seismic data. A detailed characterization of reservoir parameters relevant to geothermal water exploration and exploitation is presented for the selected prospective area.
PL
W artykule scharakteryzowano górnojurajskie wapienie ze złóż w rejonie Działoszyna, udokumentowane dla potrzeb przemysłu cementowego, wapienniczego i do produkcji kamienia budowlanego. Przedstawiono najważniejsze parametry chemiczne oraz fizyczne i mechaniczne wapieni z eksploatowanych złóż oraz dane na temat wielkości wydobycia i dostępnych zasobów. Wśród kompleksów skalnych oksfordu, charakteryzujących się zróżnicowanym udziałem wapieni, wapieni marglistych i margli, szczególne znaczenie ma odmiana wapieni zalesiackich. Skały te poddane zostały szczegółowej charakterystyce w zakresie wykształcenia litologicznego, parametrów jakościowych oraz kierunków gospodarczego wykorzystania.
EN
The paper presents the characteristics of the Jurassic limestones from deposits in the Działoszyn area, recognized as a rock minerals for the cement and lime industry and for the production of construction stone. The most important chemical, physical and mechanical parameters of limestone from exploited deposits as well as data on the mining output volume and available resources are presented. Among the Oxford rock complexes, comprises of limestones, marly limestones and marls that occurs in various proportions, the type of Zalesiaki limestones is of particular importance. These rocks were subjected to detailed analyses in terms of variability of lithological features, quality parameters and directions of economic use.
EN
The Upper Jurassic carbonates representing the microbial-sponge megafacies in the area of the Kraków-Częstochowa Upland (KCU) were locally silicified. In the reclaimed Lipówki Quarry, in Rudniki near Częstochowa (in the northern part of the Upland), macroscopically different silicification products were observed in blocks of Upper Jurassic limestones, deposited as mining waste. Two varieties were distinguished: (i) chert concretions representing the I silicification stage and (ii) light-brown, silicified limestones infilling the fractures in chert concretions or forming the cortices around the concretions or forming irregular bodies, all representing the II silicification stage. The diagnostic features are the following: (i) macroscopic development, (ii) the presence of moganite exclusively in chert concretions and (iii) significant differences in crystallinity index (CI) values, namely: 0.1–0.7 for chert concretions and 6.0–6.6 for silicified limestones. The formation of chert concretions was initiated as early as in unconsolidated sediment, whereas the II silicification stage followed the chemical compaction of the limestones. The results of geochemical analyses of the products of both silicification stages indicated that the probable source of silica were the low-temperature hydrothermal solutions. Two types of fractures were found in the chert concretions, generated during different tectonic events. The older, open fractures were formed during the extension of the Late Jurassic sedimentary basin, which formerly occupied the territory of the more recent KCU. These fractures were infilled with unconsolidated, fine-detrital carbonate sediment, in which the concretions were embedded and finally silicified in the II silicification stage. The younger, closed fractures, transversal to those filled by the products of II silicification stage, along which small displacements are evident, document the later tectonic deformations presumably related to Cenozoic faulting.
EN
Foraminifera, ammonites, and calcareous dinoflagellates were used for stratigraphy and, together with microfacies, for the assessment of the palaeoenvironmental conditions of the Upper Jurassic deposits in the central Alborz Zone of northern Iran. The Lar Formation (Lar Fm.) in the Polur section is of latest Oxfordian to early Kimmeridgian age. The ammonite Subnebrodites planula and the calcareous dinoflagellate Colomisphaera nagyi have been introduced as new biomarkers of the lower Kimmeridgian in the central Neo-Tethys. The distribution of calcareous dinoflagellates reflects possible dispersal routes along a narrow seaway between the western Neo-Tethys and the Alborz Zone in the central Neo-Tethys. The Terebella-Crescentiella associations of the Lar Fm. represent a low-energy setting under dysoxic conditions in the Central Neo-Tethys Ocean. The benthic foraminiferal assemblages in this formation show a high dominance of infaunal taxa and r-selected strategists. This assemblage is reminiscent of eutrophic conditions and low oxygen levels in the lower part of the Lar Fm. Good preservation of the hexactinellid sponges in the upper part of the Lar Fm. also indicates an oxygen-minimum zone. Three third-order depositional sequences can be distinguished in the study area based on six microfacies. Depositional sequence 1 (DS1) is composed mainly of argillaceous limestone and medium- to thick-bedded limestone, corresponding to an outer ramp-to-middle ramp environment. Depositional sequence 2 (DS2) comprises breccia limestone and thick-bedded limestone facies in its lower part and thin-bedded limestone to massive limestone in its upper part. The breccia limestone facies may be associated with subaerial exposure and reworking of previously deposited sediment during a relative sea level fall. The thin-bedded limestone to massive limestone of DS2 consists mainly of bioclastic mudstone to wackestone (outer ramp). These represent an deep-water outer homoclinal ramp facies. Depositional sequence 3 (DS3) consists mainly of massive limestone to thick-bedded limestone with a bioclastic peloidal microbial Crescentiella packstone (middle ramp). The relative stratigraphic positions of DSs1–3 and sequence boundaries in the uppermost Oxfordian to lower Kimmeridgian of the Polur area show a fair match to the upper Oxfordian to lower Kimmeridgian sequences (JOx7, JOx8, JKi1 and JKi2) on the global sea level curve.
EN
A relatively rich assemblage of starfish is recognised from the talus facies of an Upper Jurassic (lower Kimmeridgian) biohermal, sponge-cyanobacterial build-up from the Wapienno/Bielawy succession exposed in a salt-dome anticline in Kuyavia region, north-central Poland. The paper presents 8 taxa belonging to 4 genera (one new to science): Boxaster gen. nov., Noviaster Valette, 1929, Tylasteria Valette, 1929, Valettaster Lambert, 1914, and 4 families: Astropectinidae Gray, 1840, Goniasteridae Forbes, 1841, Sphaerasteridae Schöndorf, 1906 and Stauranderasteridae Spencer, 1913. Only a very few representatives of some of these taxa have formerly been reported from the Jurassic of Poland. Two species are new: Valettaster planus sp. nov. and Boxaster wapienensis gen. et sp. nov. The Jurassic starfish assemblage recognised from the Wapienno/Bielawy succession is interpreted as an offshore starfish fauna with the admixture of allochtonous shallow-water taxa. The lithology of the source deposits indicates their transport by storm agitation and/or mass movements. This fact strongly influenced the preservation state, all collected plates being disarticulated and most of them abraded.
EN
The source of clastic material supplied to the epicontinental sea during the Middle and Late Jurassic in the Pomeranian Segment of the northern part of the Mid-Polish Trough is analysed, using deposits from the Rzeczyn PIG-1 borehole that represent the Łyna, Chociwel, Brda, Pałuki, Kcynia and Rogoźno formations. Heavy mineral analysis, including weathering indices (ZTR, GZI, RZI and Q) and standardised scores for each mineral species, shows that each formation is characterized by a different heavy minerals association. In each association, transparent minerals include both ultrastable minerals (zircon, tourmaline and rutile), occurring in various proportions, and unstable minerals. This indicates that deposits subject to earlier multiple reworking were eroded from the surrounding landmasses. Most probably these deposits represented Triassic rocks, although fresh weathering covers were also eroded. The main direction of clastic material supply was from the N and NW, and to a lesser degree from the NE. The main reasons for changes in the source areas were probably sea level oscillations, while during regressions, exposed parts of the seabed became source areas of clastic material. Conversely, during transgressions, parts of the seabed became cut off from the supply of clastic material from eroded landmasses.
EN
The stratigraphical interval of the Kimmeridgian between the Bimammatum and the Hypselocylum zones in the SW margin of the Holy Cross Mts. shows a transition from the open shelf deep-neritic sponge megafacies to the shallow-water carbonate platform, including its development and decline. The uniform progradation of the shallow-water carbonate platform occurred at the end of the Planula Chron. Development of the shallow-water carbonate platform was controlled by climatic and tectonic factors. The former induced by orbital cyclicity resulted in changes of sea-level, revealed i.a. by the incoming of open-marine ammonite faunas, the latter were related to the synsedimentary activity of faults which resulted in contrasted facies changes. The episodically occurring strong influx of siliciclastic material was at least partly controlled by the tectonic activity. The newly elaborated formal lithostratigraphic subdivision takes into account the facies development of the succession in relation to climatically and tectonically induced changes. Such is e.g. the Małogoszcz Oolite Formation, corresponding to a single 100-kyr eccentricity cycle from the late Platynota Chron to the earliest Hypselocyclum Chron, bordered from the base and top by two transgressive climatically-controlled levels. The final stage of the shallow-water platform development at the end of the Hypselocyclum Chron was marked by the successive limitation of restricted environments, and the appearance of more open-marine conditions related to tectonic subsidence of the area of study. Comparison between the carbonate platform development of the Holy Cross Mts. in central Poland, and the coeval shallow-water carbonates of the Jura Mts. in northern Switzerland and south-eastern France provides an opportunity to consider similarities in the successions which can be attributed to the climatically-controlled sedimentary cyclicity and/or the wide-ranged tectonic phenomena. The palaeontological part of the study gives comments on the classification and phylogeny of ammonites of the families Ataxioceratidae and Aulacostephanidae.
EN
Vertebrate remains, mostly cryptodiran turtle shellfragments, pliosaur skull bones and teeth, plesiosaur vertebrae and crocodylomorph isolated teeth and skull fragments are described from the Upper Jurassic (Kimmeridgian) limestone beds of Krzyżanowice in the NE margin of the Holy Cross Mountains in Poland. The vertebrate fossils were collected during the palaeontological excavations conducted in 2018 and 2019 by the authors, and in the 1960s by a scientific team from the Museum of the Earth and the Institute of Paleobiology Polish Academy of Sciences. All osteological remains are generally very well preserved. This interesting vertebrate bones association from the upper part of the Kimmeridgian represents fossils of animals from two different types of environment. The first contains costal reptiles, like turtles and crocodylomorphs, the second one contains large pelagic animals - pliosaurids and plesiosaurids. This new vertebrate fauna from Poland has been correlated with age-equivalents from other regions of Europe and both Boreal/Subboreal and Mediterranean palaeobiogeographical realms.
EN
Oxygen and carbon isotope ratios of well-preserved calcitic bivalves from the Lower-lowermost Upper Kimmeridgian of Central Poland (SW margin of the Holy Cross Mountains) have been studied to reconstruct palaeoenvironmental conditions and variations in ancient water chemistry. Low and scattered δ18O and δ13C values of bivalve shells from shallow carbonate deposits of the Hypselocyclum and the Hypselocyclum-Divisum zone boundary (-3.5 to -1.5, and 2.6 to 4.0‰, respectively) are a result of salinity changes, and local variations in the composition of dissolved inorganic carbon (DIC) in conditions of restricted water circulation. A slight increase in bivalve δ13C values and more densely clustering of δ18O values is observed after the marine transgression at the Divisum-Mutabilis zone boundary. A global decrease of δ13C values of marine carbonates is partly recorded in Lower-lowermost Upper Kimmeridgian bulk carbonates from central Poland (from the Radomsko Elevation and the Wieluń Upland). Local negative shifts and the data scatter are, however, observed in rocks deposited in a very shallow environment of carbonate platforms during the Platynota and Hypselocyclum chrons. This interval corresponds to the uppermost part of the lowstand systems track of a major regressive trend, which had started already in the Late Oxfordian.
EN
New data are presented in relation to the worldwide definition of the Oxfordian/Kimmeridgian boundary, i.e. the base of the Kimmeridgian Stage. This data, mostly acquired in the past decade, supports the 2006 proposal to make the uniform boundary of the stages in the Flodigarry section at Staffin Bay on the Isle of Skye, northern Scotland. This boundary is based on the Subboreal-Boreal ammonite successions, and it is distinguished by the Pictonia flodigarriensis horizon at the base of the Subboreal Baylei Zone, and which corresponds precisely to the base of the Boreal Bauhini Zone. The boundary lies in the 0.16 m interval (1.24–1.08 m) below bed 36 in sections F6 at Flodigarry and it is thus proposed as the GSSP for the Oxfordian/ Kimmeridgian boundary. This boundary is recognized also by other stratigraphical data – palaeontological, geochemical and palaeomagnetic (including its well documented position close to the boundary between magnetozones F3n, and F3r which is placed in the 0.20 m interval – 1.28 m to 1.48 m below bed 36 – the latter corresponding to marine magnetic anomaly M26r). The boundary is clearly recognizable also in other sections of the Subboreal and Boreal areas discussed in the study, including southern England, Pomerania and the Peri-Baltic Syneclise, Russian Platform, Northern Central Siberia, Franz-Josef Land, Barents Sea and Norwegian Sea. It can be recognized also in the Submediterranean-Mediterranean areas of Europe and Asia where it correlates with the boundary between the Hypselum and the Bimmamatum ammonite zones. The changes in ammonite faunas at the boundary of these ammonite zones – mostly of ammonites of the families Aspidoceratidae and Oppeliidae – also enables the recognition of the boundary in the Tethyan and Indo-Pacific areas – such as the central part of the Americas (Cuba, Mexico), southern America, and southern parts of Asia. The climatic and environmental changes near to the Oxfordian/Kimmeridgian boundary discussed in the study relate mostly to the European areas. They show that very unstable environments at the end of the Oxfordian were subsequently replaced by more stable conditions representing a generally warming trend during the earliest Kimmeridgian. The definition of the boundary between the Oxfordian and Kimmeridgian as given in this study results in its wide correlation potential and means that it can be recognized in the different marine successions of the World.
EN
The Owadów-Brzezinki quarry is one of the most important paleontological sites in Poland, known from its exceptionally well-preserved Late Jurassic (Tithonian) fossils of marine and terrestrial biota, including horseshoe crabs and decapod crustaceans, rare ammonites, various insects and pterosaurs. This paper describes the discovery of new, well preserved reptile bones (ichthyosaurs, turtles and crocodylomorphs), which adds sigmficantly to our knowledge of these three gr°upü. The occurrence of large marine reptiles show open marine connections with the Sub- boreal-Boreal areas (both with Subboreal English seas and Boreal Arctic areas), and the Submediterranean Province (corresponding to the area of southern Germany).
EN
New biostratigraphical and carbon isotope data are presented for the Upper Jurassic limestones of the Raptawicka Turnia Limestone Formation (High Tatric unit, Western Tatra Mountains, Poland) from the Mały Giewont area. The Kimmeridgian, lower Tithonian and lower part of the upper Tithonian have been identified on the basis of calcareous dinocysts and calpionellids. Eight microfossil biozones are distinguished: acme Fibrata, acme Parvula, Moluccana, Borzai, Tithonica acme Pulla(?), Malmica, Chitinoidella and Crassicollaria (pars). The Kimmeridgian/Tithonian boundary is indicated at the top of the Borzai Zone 76 m above the base of the Raptawicka Turnia Limestone Formation. The microfossil stratigraphy suggests the late Early Kimmeridgian age (acme Parvula Zone) of the ammonites described by Passendorfer (1928). The taxon Taramelliceras ex gr. compsum found 14 m above those ammonites is Late Kimmeridgian in age. Seven microfacies types (MF) are identified in the Upper Jurassic limestones of the Mały Giewont area. The Bositra-Saccocomidae MF occurs across the Lower-Upper Kimmeridgian boundary. The planktonic and benthic foraminifera occur in the Upper Jurassic deposits of the Raptawicka Turnia Limestone Formation. The genera Lenticulina Lamarck and Spirillina Ehrenberg are common in the Kimmeridgian and Tithonian limestones. The palaeobathymetric evolution of the Kimmeridgian-Tithonian deposition recorded in the Mały Giewont sections reveals: the transgressive episode at the Lower/Upper Kimmeridgian boundary interval, the transgression peak during the Early Tithonian (Malmica Zone) and gradual shallowing of the High-Tatric swell in the Late Tithonian. Integrated isotope stratigraphy and biostratigraphy enabled correlation with the pelagic section of the Sub-Tatric succession in the Długa Valley section. The middle part of the Raptawicka Turnia Limestone Formation (Upper Kimmeridgian) might be correlated with the upper part of the Czajakowa Radiolarite Formation (red radiolarites) and Czorsztyn Formation in the Długa Valley section. The upper part of the Raptawicka Turnia Limestone Formation of Early Tithonian age corresponds mostly to the Jasenina Formation. The overall similarity of the δ13C decreasing values recorded in the Kimmeridgian–earliest Tithonian interval of the Mały Giewont (this study) and Długa Valley sections indicates that the generally shallow-water deposits of the Raptawicka Turnia Limestone Formation accumulated below the zone influenced by changes in the composition of marine water caused, for instance, by intense rainfalls.
PL
Z badań składu chemicznego i izotopowego wód górnojurajskiego poziomu wodonośnego rejonu Buska-Zdroju i Solca- Zdroju wynika, że są to solanki pierwotne i wody słone, zasilane w okresie przedplejstoceńskim, kiedy klimat charakteryzował się długimi okresami znacznie cieplejszymi niż współcześnie. Solanki te mają zdecydowanie cięższy skład izotopowy niż wody lecznicze, siarczkowe występujące na tym obszarze w utworach kredowych (głównie cenomanu) oraz zbliżone wartości wskaźników hydrochemicznych do wód morskich.
EN
The study of the chemical and isotopic composition of the Upper Jurassic aquifer in the Busko-Zdrój and Solec-Zdrój region suggests primary nature of the brines supplied before the Pleistocene under climate conditions characterized by long and much warmer periods than today. Compared to the sulphide healing waters occurring in the Cretaceous formations, mainly of Cenomanian age, the discussed brines and salt water are characterized by a far heavier isotopic composition as well as by the values of hydrochemical indica¬tors mostly similar to those of marine waters.
EN
The Buila-Vânturariţa Massif consists of massive Upper Jurassic reef limestones (Kimmeridgian–Tithonian) and Lower Cretaceous (Berriasian–Valanginian, and Barremian–?Lower Aptian) deposits. Besides corals and stromatoporoids, a wide range of micro-encrusters and microbialites has contributed to their development. In this study, the authors describe briefly and interpret the main facies associations and present the microfossil assemblages that are important for age determination. The distribution of facies associations, corroborated with the micropalaeontological content and early diagenetic features, indicate different depositional environments. The carbonate successions show the evolution of the Late Jurassic–Early Cretaceous depositional environments from slope and reef-front to internal-platform sedimentary settings, including peritidal environments in the lowermost Cretaceous. Early diagenesis, represented by synsedimentary cementation in the form of micritization (including cement crusts in the reef microframework), followed by dissolution, cementation and dolomitization in a meteoric regime, and void-filling late cementation during the burial stage.
EN
Benthic foraminifera, tintinnids and calcareous dinocysts provide new important biostratigraphic data on the age of the Raptawicka Turnia Limestone Formation and Wysoka Turnia Limestone Formation of the NiedŸwiedŸ crag geological section in the Polish Western Tatra Mts. Foraminiferal assemblages of shallow- water limestones from the NiedŸwiedŸ section contain some stratigraphically significant species, including Haghimashella arcuata (Haeusler), Protomarssonella kummi (Zedler), Uvigerinammina uvigeriniformis (Seibold & Seibold) and Textulariopsis jurassica (Guembel). Sporadic planktonic microfossils, such as the tintinnid Tintinnopsella carpathica (Murgeanu & Filipescu), calcareous dinocysts (Cadosina minuta Borza, Colomisphaera lucida Borza, C. tenuis (Nagy), C. varia Øechanek and Parastomiosphaera malmica (Borza), have also been identified. On the basis of these microfossil assemblages the lower and middle parts of the NiedŸwiedŸ section was dated as the Lower Tithonian–Barremian. Limestones of the Raptawicka Turnia Limestone Formation section represent peloidal, peloidal-oolitic and peloidal-oolitic-bioclastic facies. Limestones from the Wysoka Turnia Limestone Formation of the NiedŸwiedŸ section was dated as the Upper Barremian–Lower Aptian, based on a specific composition of foraminifera assemblages, that suggest an eroded carbonate platform as a source of Urgonian-type carbonate material. The boundary between the formations occurs within a poorly dated interval (Valanginian–Barremian).
EN
Two partial skeletons of allosaurid theropods belonging to an adult and a juvenile from the Upper Jurassic (Tithonian) Morrison Formation of McElmo Canyon in Montezuma County, southwestern Colorado, were discovered in 1953 by the late Joseph T. Gregory and David Techter. The adult specimen consists of several isolated cranial and postcranial skeletal elements that are exceptionally well-preserved and include the left premaxilla, maxilla, dentary, teeth, quadratojugal, two caudal vertebrae, pubic peduncle, ischium, proximal tibia, a nearly complete left foot, and several isolated teeth, whereas the juvenile specimen is represented by the distal portion of the right dentary and a fragmentary splenial. The specimens represent a new species of Allosaurus, here named Allosaurus lucasi, which differs from Allosaurus fragilis by having a relatively short premaxilla and robust quadratojugal with short jugal process and a short quadrate process of the quadratojugal that is at the same level as the rostral quadratojugal ramus. The presence of a new species of Allosaurus in the Tithonian of North America provides further evidence of the taxonomic and morphological diversity of the Allosauridae clade and their continuous evolutionary success, which extended to the Cretaceous.
EN
In 1879, Othniel C. Marsh and Arthur Lakes collected in the Upper Jurassic Morrison Formation Quarry 12 at Como Bluff, Wyoming, USA, several isolated axial and appendicular skeletal elements of small theropod dinosaurs. Since the discovery the specimens remained unnoticed for over a century. The skeletal remains of small theropods are rare at Como Bluff and throughout the Morrison Formation. Their bones are delicately constructed, so they are not as well-preserved as the bones of large-bodied theropods. The bones of small theropods described here were found mixed with isolated crocodile teeth and turtle shells. Comparison of the skeletal materials with other known theropods from the Morrison Formation reveals that some of the bones belong to a very small juvenile Allosaurus fragilis and Torvosaurus tanneri and also to a new ceratosaur taxon, here named Fosterovenator churei, whereas the other bones represent previously unidentified juvenile taxa of basal tetanuran and coelurid theropods. The discovery and description of these fossil materials is significant because they provide important information about the Upper Jurassic terrestrial fauna of Quarry 12, Como Bluff, Wyoming. The presence of previously unidentified theropod taxa in the Morrison Formation indicates that the diversity of basal tetanuran and coelurid theropods may have been much greater than previously expected. Although the fossil material here described is largely fragmentary, it is tenable that theropods of different clades co-existed in the same ecosystems at the same time and most likely competed for the same food sources.
EN
The ammonite succession in the stratigraphical interval from the Bifurcatus Zone, through the Hypselum Zone, up to the lower part of the Bimammatum Zone corresponding to a large part of the Submediterranean Upper Oxfordian is studied in several sections of the Polish Jura in central Poland. The sections have yielded numerous ammonites of Submediterranean–Mediterranean affinity, but also, some of Boreal and Subboreal character. The co-occurrence of ammonites of different bioprovinces makes possible the correlation between the different zonal schemes – especially between the Subboreal/Boreal zonations and the Submediterranean/Mediterranean zonation. The correlation shows that the boundary of the Pseudocordata and Baylei zones (Subboreal) and its equivalent – the boundary of the Rosenkrantzi and Bauhini zones (Boreal), currently proposed as the primary standard of the Oxfordian-Kimmeridgian boundary within its GSSP at Staffin Bay (Isle of Skye, Scotland), runs in the Submediterranean/Mediterranean Upper Oxfordian near the base of the Bimammatum Zone. This discovery removes the main obstacle against the formal recognition of the Staffin Bay section as representing the uniform base of the Kimmeridgian Stage in the World and its GSSP. The ammonite taxa recognized are commented on and/or described, and suggestions on their taxonomical and phylogenetical relations are given in the palaeontological part of the study. A new taxon is established: Microbiplices anglicus vieluniensis subsp. nov.
EN
A development project of the Zalew Balaton area is being presently carried out. One of the project assumptions is to create a geological path across the object. However, detailed data about the geological structure of this place is not available. For this reason, the author has researched and updated the information about the rocks occurring in the walls of the old quarry. Primarily, terrain (textural and structural analysis, layers strike and dip measurements, geological boundaries delimitation) and laboratory analysis (X-Ray Powder Diffraction, microscopic rock samples analysis) were conducted. Collected data was afterwards compared with available literature. Within the steep slopes of excavation, strong-karsted, faulted Upper Jurassic (Oxfordian) carbonate sediments were revealed. These are massive, platy and crumpled limestone. These rocks could be deposited in changing conditions of sedimentation, when calm carbonate sedimentation was disturbed by underwater gravity flows, as demonstrated by their detrital character. One of the karst funnel on the northern slope was filled with Oligocene sand. As a result, groundwater fluctuations created a sarsen structure, popularly called the “Wielbłąd”. In relation to the planned geological path across the Zalew Balaton area, previous knowledge should be supplemented with new data, respectively processed and included on information panes, located within object. Plans of the path should pay attention to potential geotouristic safety, as well as to the geological values of the protected object, during its future modernization.
PL
Przedstawiono wyniki badań utworów jury górnej w dwóch peźnordzeniowych profilach wierceń, które opracowano przy realizacji „Zintegrowanego programu płytkich wierceń badawczych dla rozwiązania istotnych problemów budowy geologicznej Polski”. Utwory jury górnej reprezentują megafację gąbkową. Profil otworu wiertniczego Trojanowice 2 charakteryzuje biohermalny obszar facjalny w obrębie całej przewierconej części profilu oksfordu (od oksfordu dolnego do najniższej części poziomu Bimammatum oksfordu górnego). Profil Cianowice 2 charakteryzuje basenowy obszar facjalny (miedzybiohermalny basen Korzkwi) w obrębie niemal kompletnego stratygraficznie oksfordu. Znaczne różnice reliefu dna zbiornika wykazane na podstawie precyzyjnej biostratygrafii predysponowały do różnego rodzaju ruchów masowych. Utwory reprezentujące efekty takich ruchów rozpoznano w wyższej części profilu Cianowice 2. Stwierdzono, że zróżnicowanie na dwa wymienione powyżej obszary facjalne rozpoczęło się z początkiem późnego keloweju. Określono gęstość mumii gąbkowych w biohermie otworu wiertniczego Trojanowice 2. Zmieniała się ona od kilku do 63 mumii na metr bieżący profilu. W liczącym 201 m profilu doliczono się 2199 „generacji” gąbek krzemionkowych. Dla tego samego profilu wiercenia obliczono skrócenie profilu wapieni biohermalnych w wyniku procesu rozpuszczania pod ciśnieniem (stylolityzacji wzdłuż płaszczyzn poziomych). Minimalne skrócenie, obliczane jako amplituda stylolitu, wyniosło średnio 11,6%.
EN
We present the results of research in two Upper Jurassic drill core sections which were conducted with in the frames of “Integrated research program of shallow drillings to solve the major problems of geology of Poland”. The sections represent the Upper Jurassic sponge megafacies. The Trojanowice 2 drill core records the biohermal Oxfordian facies (from the Lower Oxfordian to the lowermost part of Bimammatum Zone of the Upper Oxfordian). The Cianowice 2 section is characterized by a facies typical of interbiohermal basins (Korzkiew Basin) and shows a nearly complete Oxfordian stratigraphic section. Significant differences of the sea bottom relief shown by the precise biostratigraphic method, evoked various types of mass movements. Rocks representing the effects of such movements have been recognized in the upper part of the Cianowice 2 drill core. The differences between the two regions mentioned above are evident from the beginning of the Late Callovian. We have determined the density of the sponge mummies in the Trojanowice 2 drill core. It varied from a few to 63 mummies per 1 metre of the section. In the 201-m long profile, a total of 2199 “generations” of siliceous sponges were found. In the same profile, we calculated the shortening of the limestone thickness as a result of pressure dissolution (along a horizontal plane). The minimal shortening, calculated as the stylolite amplitude, was averagely 11.6%.
first rewind previous Strona / 5 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.