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Detailed biostratigraphy of the Middle Callovian – lowest Oxfordian in the Mikhaylov reference section (Ryazan region, European part of Russia) by ammonites

Kiselev D. N., Rogov M. A.

Volumina Jurassica

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2018

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Vol. 16, no 1

73--186

EN

Study of the sections near the Mikhaylov (Ryazan region) has made it possible to improve the infrazonal subdivision of the Middle Callovian – Lower Oxfordian of the European Russia by ammonites. The Athleta Zone is the most complete in the studied sections. A sequence of kosmoceratid biohorizons (phaeinum, proniae, rowlstonense and kuklikum) is established here, as well as infrazonal units based on a phylogenetic sequence of species of the genus Funiferites. A study of the paleobiodiversity and frequency of occurrence of ammonites at different intervals of the section showed that the ammonite assemblages of the Athleta Zone are Sub-Boreal or Sub-Tethyan, while in the Lamberti Zone they are Boreal, and in the Lower Oxfordian they are Arctic. It is also shown that the change in ammonite composition in the sections coincides with the cycles of transgressions and regressions of Boreal basins. New species and subspecies of the ammonites Funiferites allae compressum, Cadoceras (Eichwaldiceras) intermedium, Brightia (B.) lominadzei, B. (B.) progzhellensis, B. (B.) eccentrtica, B. (Glyptia) canaliculata stankevitchae, Zieteniceras rarecostatum are described.

2

How to kill the street without destroying the buildings

Samuels I.

Technical Transactions

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2018

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Vol. 115, iss. 1

5--18

EN

A discussion of the manner in which Oxford University institutions have modified the historic street structure and its character by acquiring whole blocks or by inserting new buildings, which ignore the street context, in the pursuit of promotional advantages.

PL

Artykuł stanowi omówienie sposobu, w jaki instytucje Uniwersytetu Oksfordzkiego zmodyfikowały historyczną strukturę ulicy i jej charakter poprzez nabycie całych bloków lub wstawienie nowych budynków, których obecność bagatelizuje kontekst uliczny w dążeniu do korzyści promocyjnych.

3

Comments on the identification of Ammonites planula Hehl in Zieten, 1830 (Upper Jurassic, SW Germany)

Schweigert G., Kuschel H.

Volumina Jurassica

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2017

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Vol. 15, no 1

1--16

EN

Ammonites planula Hehl in Zieten, 1830 is the type species of the Late Jurassic ammonite genus Subnebrodites Spath, 1925 and the index species of the well-established Planula Zone of the Submediterranean Province. Recently, Enay and Howarth (2017) classified this stratigraphically important ammonite species as a ʻnomen dubiumʼ and considered it to be the possible macroconch counterpart of Idoceras balderum (Oppel, 1863). These authors claimed “Subnebrodites planula Spath, 1925” instead of Ammonites planula (Hehl in Zieten, 1830) to be the type species of Subnebrodites. However, their nomenclatorial acts are based on erroneous assumptions. For future taxonomic stability we here propose a neotype for Ammonites planula (Hehl in Zieten, 1830) and a lectotype for Ammonites planula gigas Quenstedt, 1888. In addition, dimorphism within the stratigraphically much younger Idoceras balderum (Oppel) is demonstrated showing that there is no morphological resemblance and no closer relationship with Ammonites planula (Hehl in Zieten, 1830).

4

Biostratigraphy, geochemistry and sedimentology of Middle to Late Jurassic strata in the Strážovce section (Strážovské vrchy Mts), Krížna Nappe of the Central Carpathians, Slovakia

Michalík J., Bąk M., Lintnerová O., Méres Š

Volumina Jurassica

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2017

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Vol. 15, no 1

161--178

EN

The Jurassic / Lower Cretaceous sequence of the Strážovce section has been deposited in the central, axial part of the Zliechov Basin. Its most characteristic part – the Ždiar Formation consists of bedded siliceous radiolarian limestones and radiolarites. The radiolar¬ian assemblage typical of the North Tethyan Bioprovince lived during mid Oxfordian – Early Kimmeridgian in a warm upper part of the well stratified water column, partially near to the thermocline. Radiolarian abundance decreases upwards. Productivity decrease is quanti¬fied by the share of biogenic SiO2 as well as by high EFSi values during sedimentation of both the Ždiar and Jasenina formations. The geochemical data indicate relatively stable volume of the siliciclastic component of the rocks and a felsic character comparable to the Average Shale. The chemically homogeneous sedimentary signal indicates values of both CPA and EF ≤ 1 of Ti, Zr, Fe, Na, K, Rb, V and U. The values of EF > 1 signal enrichment of elements with affinity to carbonate minerals (Sr, Mn, P, Y, and Mg). Metal enrichment (Cu, Zn and Ni) indicates metal mobilization from other sources or due to carbonate diagenesis. In comparison to the Average Shale, decreased ΣREE´s and negative Cech and Euch anomalies could be regarded as a typical deep sea water signal. The differentiated REE record of higher calcareous beds of the Jasenina Fm. suggests basinal dysoxic conditions. The “bell-shape” of curves (normalized to shale) indicate that REEs were slightly affected by carbonate diagenesis. The Oxfordian / Kimmeridgian siliceous sedimentation in the Zliechov Basin was influenced probably more by monsoon-controlled input of land derived weathered material than by hydrothermal fluids from the bottom rifts.

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Sequence stratigraphy of the Oxfordian to Tithonian sediments (Baisakhi Formation) in the Jaisalmer Basin

Pandey D. K., Pooniya D.

Volumina Jurassica

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2015

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Vol. 13, no. 1

65--76

EN

The Oxfordian to Tithonian sediments deposited along the southern Tethyan margin exhibit very diverse sedimentary facies. The Jaisalmer Basin, situated along the northwestern margin of the Indian peninsula, is a good example of those preserving these sediments (Baisakhi Formation). The scattered nature of the outcrops, due to peneplanation and desert sand cover, and the diversity in sedimentary facies, have led earlier workers to employ a confusing lithostratigraphy and lithostratigraphic correlations. New records of ammonites, more detailed facies description and the application of the sequence stratigraphic method helped to sort out the stratigraphical problems of these isolated outcrops. The complexity of the Oxfordian-Kimmeridgian-Tithonian sediments present in the Jaisalmer Basin, as evidenced by ammonite finds can be traced along an onshore – offshore transect. Within the Oxfordian-Tithonian strata of the Baisakhi Formation, Jaisalmer Basin, 35 parasequences grouped into three depositional sequences (TST-HST/FSST) have been recognized. In at least two cases, the maximum flooding surfaces (MFS) are superimposed on the transgressive surfaces within very condensed sections. The parasequences belong to a continuous succession representing shoreface (deepest part of the basin) to foreshore (shallowest part of the basin). During deposition of the Tithonian succession the southern part of the basin witnessed shallow, nearshore, or foreshore to fluvial depositional environments and, consequently, contains several depositional gaps and less distinct parasequences. The chronological order of the parasequences has been established on the basis of ammonites: Oxfordian – Perisphinctes (Dichotomosphinctes) sp. and P. (Dichotomoceras) sp.; Kimmeridgian – Torquatisphinctes alterniplicatus (Waagen) and Pachysphinctes aff. major Spath; Tithonian – Aulacosphinctoides sp., Virgatosphinctinae and other zonal ammonites recorded by earlier workers. The most logical facies correlation in conformity with Walther’s law was also used. Unfortunately, no marker beds have been recognized; however, the record of at least two brackish-water phases helped in the understanding of depositional settings along the onshore-offshore transects during these time intervals. In general, the Kimmeridgian-Tithonian part of Baisakhi Formation exhibits a general coarsening-upward trend and a change from lower shoreface zone to fluvial environments. The three sequence cycles interpreted within the Oxfordian-Tithonian sediments in the Jaisalmer Basin correspond to second-order sequence cycles.

6

Report of the Oxfordian Task Group (OTG) Meeting : the section of Ham Cliff, Redcliff Point, Weymouth, UK (11-14th June 2014)

Meléndez G., Page K. N.

Volumina Jurassica

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2015

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Vol. 13, no. 2

159--163

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Integrated biostratigraphy of the Jurassic strata of the Wagad Uplift, Kachchh, western India

Rai J., Garg S., Gupta M., Singh A., Pandey D. K., Fürsich F. T., Alberti M., Garg R.

Volumina Jurassica

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2015

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Vol. 13, no. 2

55--80

EN

An integrated study based on calcareous nannofossils, organic-walled dinoflagellate cysts, and ammonites from the Washtawa and Kanthkot formations of the Wagad Uplift have allowed a detailed documentation of the stratigraphic position of these formations within the Oxfordian and Kimmeridgian sediments of the Kachchh Basin, western India. The nannofossil assemblages from the lower part of the Nara Shale Member exposed in the Nara and Washtawa domes, the Kanthkot Ammonite Beds along the Trambau River section, and the Patasar Shale Member exposed along the Trambau River section and the Patasar Tank section in the eastern part of the Wagad Uplift belong to the NJ 14 Cyclagelosphaera margerelli Zone of the Early Oxfordian, the NJ 15a Lotharingius sigillatus Zone of the Middle Oxfordian, and the NJ 15b Cretarhabdus conicus of Early Kimmeridgian age, respectively. Zonation schemes, based on calcareous nannofossils, dinoflagellate cysts, and ammonites were calibrated highlighting their biostratigraphic potential. These studies may represent a reference biochronology for Oxfordian–Kimmeridgian age strata applicable to the Tethyan realm of which India was a part during Late Jurassic times.

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Deformacje skamieniałości śladowych a proces kompakcji w wapieniach mikrytowych górnej jury okolic Korzkwi (Wyżyna Krakowska)

Ziółkowski P.

Volumina Jurassica

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2005

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Vol. 3, no. 1

55--61

EN

Upper Jurassie (Oxfordian, Bimmammatum Zone) micritic limestones show presence of omission surface of firmground character with trace fossils assemblage. Deformations of burrows are used to quantitative determination of mechanical compaction, applying Ricken's model. Presented results may be used in reconstruction of sea bottom relief during Late Jurassie in area of study.

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Callovian and Oxfordian echinoids of Zalas

Radwańska U.

Volumina Jurassica

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2005

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Vol. 3, no. 1

63--74

EN

Within the Callovian-to-Oxfordian sequence, transgressive upon the Variscan rhyodacite laccolith exposed at Zalas in the Cracow Upland, southern Poland, and far-known due to its ubiquitous fossils of various kinds, to this study subjected are the echinoids. The Callovian assemblage from the variably-sized clastics is low-diversified, to contain 4 taxa of a wider regional occurrence. The Lower (up to the base of Middle) Oxfordian assemblage appears the richest in the Oxfordian of Poland. Its content is typified by the representatives of the orders Cidaroida Claus, 1880, and Phymosomatoida Mortensen, 1904. Amongst the recognised 12 species, of special attention are those first reported from the Jurassic sequences of Poland, viz. Eosalenia miranda Lambert, 1905, and Heterocidaris dumortieri Cotteau, 1871, the latter of which is still a great rarity to the science. Discussed are the life requirements of some of the recognised taxa, as apparent from the functional analysis of their tests. banalnych form nieregularnych pojawia się tutaj (patrz pl. 1: 3a-3b) duży osobnik regularny, Stomechinus heberti Cotteau, 1884, nieznany dotąd w środkowej jurze Polski. Zespół jeżowców z osadów oksfordu (patrz pl. 2- 3) składa się z 12 taksonów (patrz fig. 2), spośród których sześć z podgromady Cidaroidea Claus, 1880, zostało omówionych wcześniej (Radwańska 2003). Zespół ten obejmuje wyłącznie jeżowce regularne o zbliżonych wymaganiach życiowych wskazujące na ujednolicenie warunków środowiskowych w czasie rozszerzającej się transgresji. Uwagę zwraca w nim gatunek Heterocidaris dumortieri Cotteau, 1871, o wprawdzie niejasnej pozycji systematycznej (patrz Fell 1966), a reprezentowany niestety tylko w postaci ułamków pancerzy (pl. 2: 5) znacznych rozmiarów (średnicy ponad 10 cm), ale będący niezmierną rzadkością w jurze europejskiej (patrz Cotteau 1860, 1871; Fell 1966) i nieznany dotychczas z obszaru Polski.

PL

Profil osadów jurajskich odsłaniający się w stropie wielkiego kamieniołomu waryscyjskich riodacytów Zalasu (patrz fig. 1) okazuje się znaczącym ze względu na bogactwo szczątków różnorodnych szkarłupni (liliowców, rozgwiazd, wężowideł), spośród których na szczególną uwagę zasługują jeżowce . W dotychczasowych opracowaniach profilu Zalasu, dostępnego dawniej w niewielkich odsłonięciach naturalnych lub lokalnych łomikach, jeżowce były notowane sporadycznie, jako towarzyszące obfitej faunie gąbek, amonitów i innych mięczaków, oraz ramienionogów (patrz Siemieradzki 1893; Wójcik 1910). Rozlegle odsłonięcie w kamieniołomie riodacytów, rozbudowywanym od lat 1970-tych, umożliwiło szczegółowe rozpoznanie wykształcenia facjalnego osadów jurajskich, ich inwentarza faunistycznego i przede wszystkim ich biostratygrafii wyznaczającej pozycję stratygraficzną profilu w przedziale dolny kelowej - niższa część oksfordu środkowego (patrz Giżejewska i Wieczorek 1977; Matyja i Tarkowski 1991; Tarkowski 1989). Badane przez autorkę jeżowce, pochodzące częściowo z rozmaitych kolekcji (publicznych i prywatnych), a w większości zebrane osobiście, stanowią w sumie dosyć istotny element w rozpoznaniu faun jurajskich Polski. Zespół jeżowców z osadów keloweju (patrz pl. 1) obejmuje tylko 4 gatunki (patrz fig. 2) o różnych wymaganiach życiowych wskazujących na nieustabilizowane warunki środowiskowe w czasie postępującej transgresji morskiej. Oprócz dość Analiza funkcjonalna pancerzy (patrz Smith 1978, 1984; Radwańska 1999) pozwoliła na bardziej szczegółowe rozpatrzenie sposobu życia i wymogów środowiskowych badanych gatunków jeżowców z keloweju i oksfordu Zalasu, zaś analiza taksonomiczna na unacześnienie rozpoznań autorów wcześniejszych (Siemiradzki 1893; Wójcik 1910; patrz fig, 3). Zespół jeżowców oksfordzkich Zalasu okazuje się najbogatszym spośród wszystkich dotychczas badanych stanowisk oksfordu w Polsce (por. Radwańska 2000,2003, 2004b), zaś jego środowiskowe siedlisko - wśród obfitych gąbek, ich mumii i budowli (por. Matyja i Tarkowski 1981, fig. 2B-3) - nadzwyczaj podobne do przedstawionego dla środkowego oksfordu Szwajcarii (patrz Hess 1975, fig. 27).