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The proposal of a GSSP for the Berriasian Stage (Cretaceous System): Part 2

Wimbledon William A.P., Reháková Daniela, Svobodová Andrea, Elbra Tiiu, Schnabl Petr, Pruner Petr, Šifnerová Krýstina, Kdýr Šimon, Frau Camille, Schnyder Johann, Galbrun Bruno, Vaňková Lucie, Dzyuba Oksana, Copestake Philip, Hunt Christopher O., Riccardi Alberto, Poulton Terry P., Bulot Luc G., De Lena Luis

Volumina Jurassica

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2020

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Vol. 18, no. 2

121-160

EN

In part 1 of this work we discussed the possibilities for the selection of a GSSP for the Berriasian Stage of the Cretaceous System, based on prevailing practical methods for correlation in that J/K interval, traditional usage and the consensus over the best boundary markers that had developed in the last forty years. This consensus has developed further, based on the results of multidisciplinary studies on numerous sites over the last decade. Here in Part 2 we give an account of the application of those results by the Berriasian Working Group (ISCS), and present the stratigraphic evidence that justifies the selection of the locality of Tré Maroua (Hautes-Alpes, SE France) as the proposed GSSP. We describe a 45 m-thick section in the Calcaires Blancs vocontiens – that part of the formation covering the calpionellid Chitinoidella, Remanei. Intermedia, Colomi, Alpina, Ferasini, Elliptica and Simplex biozones. The stratigraphic data collected here has been compiled as part of a wider comparative study of complementary Vocontian Basin sites (with localities at Charens, St Bertrand, Belvedere and Le Chouet). Evidence from Tré Maroua thus sits in this substantial regional biostratigraphic and magnetostratigraphic context. For the purposes of the GSSP definition, here we particularly concentrate on the unbroken sequence and biotic markers in the interval immediately below the boundary, the Colomi Subzone (covering circa 675,000 years), and immediately above, the Alpina Subzone (covering circa 725,000 years). Particularly significant fossil datums identified in the Tré Maroua profile are the primary basal Berriasian marker, the base of the Alpina Subzone (a widespread event marked by dominance of small Calpionella alpina, with rare Crassicollaria parvula and Tintinopsella carpathica): the base of the Berriasian Stage is placed at the base of bed 14, which coincides with the base of the Alpina Subzone. Secondary markers bracketing the base of the Calpionella Zone are the FOs of the calcareous nannofossil species Nannoconus wintereri, close below the boundary, and the FO of Nannoconus steinmannii minor, close above. The Tithonian/Berriasian boundary level occurs within M19n.2n, in common with many documented sites, and is just below the distinctive reversed magnetic subzone M19n.1r (the so-called Brodno reversal). We present data which is congruent with magnetostratigraphic and biostratigraphic data from other key localities in France and in wider regions (Le Chouet, Saint Bertrand, Puerto Escaño, Rio Argos, Bosso, Brodno, Kurovice, Theodosia…), and thus the characteristics and datums identified at Tré Maroua are key for correlation and, in general, they typify the J/K boundary interval in Tethys and connected seas

2

Integrated stratigraphy of the reference sections for the Callovian-Oxfordian boundary in European Russia

Kiselev D., Rogov M., Glinskikh L., Guzhikov A., Pimenov M., Mikhailov A., Dzyuba O., Matveev A., Tesakova E.

Volumina Jurassica

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2013

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Vol. 11, no. 1

59–-96

EN

The most complete succession of the Callovian-Oxfordian boundary recorded in European Russia is the Dubki section, where the authors have carried out integrated paleontological and magnetostratigraphical studies. A continuous sequence of the West-European biostratigraphic units in the interval from the Lamberti to the Cordatum Zones is present in this section, and 10 ammonite biohorizons have been recognized. Additional data concerning nannofossil assemblages, foraminifers, ostracods, belemnoids and the paleomagnetic polarity for the Dubki section are also presented. The Callovian-Oxfordian boundary, marked by FAD of the genus Cardioceras, is placed at the base of the scarburgense biohorizon. The paleontological richness and continuity of the succession make the Dubki section a possible GSSP candidate for the Callovian/Oxfordian boundary. Correlation of the Dubki ammonite succession with those of the other GSSP candidates, Redcliff Point and Thuoux, is proposed. Other sections studied in Russia have yielded some additional observations on the Callovian-Oxfordian boundary beds. Although in the Dubki section the praemartini biohorizon is not found, its existence is proved, however, in Orenburg region (Khanskaya Gora). In the Datchovskaya section (Northern Caucasus) the paucicostatum biohorizon is characterized by an unusual combination of Subtethyan and Boreal ammonites, including Kosmoceras, which is not typical of the paucicostatum biohorizon outside the Northern Caucasus.

3

Testing the congruence of the macrofossil versus microfossil record in the Turonian-Coniacian boundary succession of the Wagon Mound-Springer composite section (NE New Mexico, USA)

Walaszczyk I., Lees J., Peryt D., Cobban W., Wood C.

Acta Geologica Polonica

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2012

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Vol. 62, no. 4

581-594

EN

The Turonian-Coniacian boundary succession from the Wagon Mound-Springer composite section in the US Western Interior shows a virtually identical macrofaunal record to that revealed in the proposed candidate Coniacian GSSP in the Salzgitter-Salder-Slupia Nadbrzezna composite section in central Europe, with easy identification in both regions of the base of the Coniacian Stage, as defined by the first appearance of the inoceramid bivalve species, Cremnoceramus deformis erectus (Meek). The macrofaunal boundary definition is additionally confirmed by the foraminiferal and nannofossil data, demonstrating the high potential of the inoceramid marker for the base of the Coniacian. The former claims about distinct diachroneity between macrofossil and microfossil dates in the trans-Atlantic correlations, resulted from methodological deficiencies, and have no factual basis.

4

Pozycja chronostratygraficzna granicy neogen/czwartorzęd

Marks L.

Biuletyn Państwowego Instytutu Geologicznego

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2010

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nr 438

93--97

PL

Spełniając wieloletnie postulaty badaczy czwartorzędu, Komitet Wykonawczy Międzynarodowej Unii Nauk Geologicznych (IUGS) ratyfikował propozycję Międzynarodowej Komisji Stratygrafii obniżenia dolnej granicy czwartorzędu do dolnej granicy piętra gelas (2,588 Ma), a dolna granica plejstocenu została obniżona do tego samego poziomu. Dotychczasowa dolna granica czwartorzędu i plejstocenu, wyznaczona przez stratotyp Vrica w południowych Włoszech i datowana astronomicznie na 1,806 Ma, została utrzymana, ale jako dolna granica piętra kalabr, czyli piętra drugiego od dołu w zrekonstruowanym oddziale plejstocen. Nowa dolna granica czwartorzędu odzwierciedla moment kluczowych zmian klimatu Ziemi w pobliżu granicy epok paleomagnetycznych Gauss i Matuyama. Punkt krytyczny tych zmian został przekroczony około 2,7 Ma, kiedy nastąpiła drastyczna przebudowa cyrkulacji oceanicznej, spowodowana ostatecznym zamknięciem przesmyku panamskiego oraz zmniejszeniem zasolenia wód powierzchniowych Oceanu Arktycznego. Sprzyjało to utworzeniu stałej pokrywy lodowej w Arktyce, a wywołany tym wzrost albedo doprowadził do dramatycznej i jak dotąd nieodwracalnej ewolucji Ziemi, zdominowanej od tego czasu przez epokę lodową, z wielokrotnymi transgresjami lądolodów na kontynentach półkuli północnej.

EN

Many years’ consequent postulates of Quaternary scientists resulted in a decision of the Executive Committee of the International Union of Geological Sciences (IUGS) to ratify a proposal of the International Commission on Stratigraphy to lower the base of the Quaternary to the lower boundary of the Gelasian stage. Simultaneously, the lower boundary of the Pleistocene has been moved to the same position. The previous lower chronostratigraphic boundary of the Quaternary, represented by the Vrica stratotype in southern Italy, has been hardly recognizable outside the Mediterranean Region and neither biostratigraphic indices nor traces of extreme geological events could be found in this very place. On the other hand, an establishment of the Vrica site as the stratotype for the Neogene/Quaternary boundary (equivalent to the Pliocene/Pleistocene boundary) was a driving force to create the Gelasian as a new and uppermost stage of the Pliocene. The Gelasian filled a hiatus between the upper boundary of the Piacenzian stage at Castell Arquato and the boundary of the so-called Plio-Pleistocene at Vrica. The lower boundary of the Gelasian was defined at 2.588 Ma, close to a boundary of the palaeomagnetic epochs Gauss and Matuyama. The new lower boundary of the Quaternary reflects a principal transformation of the climate on the earth. A critical change occurred at about 2.7 Ma, when a severe reconstruction of the thermohaline circulation took place, caused by a final closure of the Panama Straits and inflow of freshwater to the Arctic Ocean. The latter favoured development of constant ice covers in the Arctic, a higher albedo of which resulted in initiation of the ice ages in the northern hemisphere.

5

The Salzgitter-Salder Quarry (Lower Saxony, Germany) and Slupia Nadbrzezna river cliff section (central Poland) : a proposed candidate composite Global Boundary Stratotype Section and Point for the Coniacian Stage (Upper Cretaceous)

Walaszczyk I., Wood C., Lees J., Peryt D., Voigt S., Wiese F.

Acta Geologica Polonica

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2010

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Vol. 60, no. 4

445-477

EN

An integrated account of a candidate composite Global Boundary Stratotype Section and Point for the base of the Coniacian Stage, comprising the Salzgitter-Salder Quarry section (Lower Saxony, Germany) and the Słupia Nadbrzeżna river cliff section (central Poland), is provided. Documented are all the main biostratigraphically significant macrofossil and microfossil groups: ammonites, bivalves (inoceramids and the genus Didymotis), planktonic foraminifera and calcareous nannoplankton. also provided are correlations based on stable carbon isotope curves. The base of the Coniacian is defined by the first occurrence (FO) of the inoceramid bivalve Cremnoceramus deformis erectus (Meek, 1876), a cladogenetic successor of the C. waltersdorfensis (Andert, 1911) lineage. This event is well above the first appearance of the classic ammonite marker of this boundary, Forresteria petrocoriensis (Coquand, 1859), which is first noted high in the Upper Turonian Mytiloides scupini inoceramid bivalve zone at Słupia Nadbrzeżna. The boundary at Salzgitter-Salder cannot be precisely defined by means of ammonites; however, there is an apparent local change in one scaphitid lineage a short distance below the boundary. In calcareous nannofossil terms, the boundary falls within the interval between the first occurrence of Broinsonia parca parca and the last occurrence (LO) of Helicolithus turonicus. at present, no planktonic species found in both sections can be used as a close proxy for the base of the Coniacian, as defined by the inoceramid bivalve marker. In terms of carbon stable isotopes, the Turonian Coniacian Boundary lies in the inflection point from falling to rising [delta^13]C values. a comparison of the Salzgitter-Salder and Słupia Nadbrzeżna carbon isotope curves indicates a hiatus at the former locality. The base of the Coniacian in the Salzgitter-Salder section is marked by a flood occurrence of Cremnoceramus deformis erectus, constituting the deformis erectus I event. The boundary interval at Słupia Nadbrzeżna is expanded: here the first occurrence of C. deformis erectus is separated from both the terminal Turonian C. waltersdorfensis waltersdorfensis event and the C. deformis erectus I event, also indicating the existence of a hiatus at the boundary in the Salzgitter-Salder section. In view of this hiatus at the critical level, it is proposed that the two sections should constitute a candidate composite Coniacian GSSP.

6

The ammonite faunas of the Callovian-Oxfordian boundary interval in Europe and their relevance to the establishment of an Oxfordian GSSP

Page K., Melendez G., Wright J.

Volumina Jurassica

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2009

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Vol. 7, no. 1

89-99

EN

At Moenkopi Wash along the Ward Terrace escarpment of northern Arizona strata of the upper Dinosaur Canyon Member of the Moenave Formation contain sedimentary structures we interpret as casts of tetrapod burrows. Sandstone casts and in situ burrows occur concentrated in two horizons that extend several hundred meters along the Ward Terrace escarpment. The structures, hosted in beds of eolian sandstone, form interconnecting networks of burrows that branch at right angles. Individual burrow casts have sub-circular cross sections and consist of nearvertical tunnels and horizontal to low-angle galleries that connect to larger chambers. Most burrow casts measure 5 to 15 cm in diameter, are filled by sandstone of similar grain size as the host rock, and have walls that are unlined and lack external ornamentation. Bedding plane exposure of the lower horizon reveals that the density of burrows exceeds 30 vertical tunnels per square meter. One exposure in the upper horizon reveals burrows concentrated in a mound-like structure with 1 m of relief. Rhizoliths, distinguished from burrows by their typical smaller diameters, calcareous infilling, and downward branching, co-occur with these burrows in the upper horizon. The fossil burrows in the Moenave Formation appear to have been constructed by a fossorial tetrapod with social behavior similar to the modern Mediterranean blind mole-rat. Although no skeletal remains are associated with the burrows, the fossil record suggests that the most likely producers of the Moenave burrows were tritylodontid cynodonts.

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Jurassic Global Stratotype Section and Points (GSSPs)-a potential serial World Heritage Site?

Page K., Melendez G., Henriques M.

Volumina Jurassica

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2008

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Vol. 6, no. 1

155-162

EN

The Operation Guidelines for the UNESCO World Heritage Convention state that proposed areas should: “..be outstanding examples representing major stages of Earth’s history, including the record of life”, “..contain all or most of the key interrelated and interdependent elements in their natural relationships”, “..have a management plan…” and “..have adequate long-term legislative, regulatory, institutional or traditional protection..”. By definition, Global Stratotype Sections and Points (GSSPs) should satisfy all these criteria, although in isolation, the proposal of any single GSSP is unlikely to succeed, however, as an individual site may lack a broader context. Nevertheless, combining a suite of GSSPs sites for a System within a ‘serial’ World Heritage site proposal would satisfy such a concern and could be an ultimate goal for the International Subcommission on Jurassic Stratigraphy.

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Towards the definition of the Triassic/Jurassic systems boundary

Bloos G.

Volumina Jurassica

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2006

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Vol. 4, no. 1

277-277

EN

This contribution summarizes the main stratigraphic results of the T/J Boundary WG since its establishment in 1988 and of the IGCP Project 458 (2001-2005); state at end of March 2006. The T/J transition in general. It begins with the main end-Triassic extinction event which is related to the negative carbon isotope excursion 13Corg. Above follows a range of strongly impoverished Triassic survivors whose duration is different in different fossil groups. Above begins the succession of Jurassic forms, sometimes at first together with last Triassic forms. Up to now (March 2006) four candidate GSSPs have been proposed: St. Audrie's Bay (Somerset, UK), Muller Canyon (Nevada, USA), Chilingote (Utcubamba Valley, Peru), and Kunga Island (British Columbia, Canada). Further important sections are known; one, situated in the Alps, will be proposed as a fifth candidate. Three possibilities to define the T/J boundary are proposed: 1. within the succession of early psiloceratids (England, Nevada); 2. at the base of the psiloceratid succession (England, Nevada, Peru); 3. at the radiolarian turnover in the T/J transitional interval (Canada). Proposal 1. It is essentially the traditional boundary since the 19 th century, indicated by the first wide-spread occurrence of psiloceratids. Since no psiloceratid species is cosmopolitan, global correlation is possible only by regional species and thus essentially tentative. The proposed correlation Psiloceras planorbis - Ps. calliphyllum - Ps. pacificum is supported by the partly proved, partly probable occurrence of the genus Neophyllites below. Since there is no difference in the associated fossil content below and above the boundary, no proxies are known which could indicate the position of the boundary where ammonites are lacking. In this case only earlier levels are available. Proposal 2. With this proposal all psiloceratids would become Jurassic. The difficulty to distinguish between Triassic and Jurassic psiloceratids would be avoided. A global correlation by ammonites would be more difficult than in "proposal 1" because such early forms are extremely rare, belong to regionally restricted species and are not proved to be coeval. First appearances of Jurassic forms in other fossil groups, particularly in palynomorphs, could be regional proxies for correlations, also with sections where ammonites are lacking. Proposal 3. New investigations suggest that the radiolarian turnover could be a global event and potentially a suitable system boundary. However, successions of sufficiently preserved radiolarians are extremely rare and they are, moreover, poor in other fossils.Therefore, the correlation with other fossil groups is diffcult and, consequently, the exact stratigraphic position of the turnover is not yet known. No proxies of other fossil groups are known to recognize the turnover in sections without radiolarians. The strong impact on the evolution of radiolarians suggests that the radiolarian turnover is close to the main end-Triassic extinction event. In this case the turnover could be situated still in latest Triassic as defined e.g. by surviving Misikella posthernsteini in Britain.

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The Triassic/Jurassic boundary beds of the Karwendel Syncline (Austria) - initial report of a new GSSP candidate for the base of the Jurassic

von Hillebrandt A., Krystyn L., Kuerschner W.

Volumina Jurassica

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2006

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Vol. 4, no. 1

287-288

EN

The northwestern part of the Northern Calcareous Alps (NCA) is famous for its fully marine and complete Triassic/Jurassic transition beds formed in an intraplatform through of the western Tethys called as Eiberg Basin (Krystyn et al. 2005). A classic boundary section (Kendlbachgraben) with a relatively rich Rhaetian invertebrate fauna is known since 150 years but with the handicap of a 15 m gap between the last Triassic (Choristoceras marshi) and the first Jurassic ammonite (Psiloceras calliphyllum). A wealth of macro- and microfaunistic information has since been added (Golebiowski 1990) favouring a TJB directly on top of the Koessen Formation (Eiberg Member), just above the disappearance of many Triassic fossil groups (ammonoids, conodonts, brachiopods). New palynological and isotopic research in the area (Kuerschner et al. in press) now points to a boundary located 6 m higher within the Tiefengraben Member (or Grenzmergel) of the lower Kendlbach Formation where along with a distinct δ ¹ ³C shift the appearance of Cerebropollenites thiergatii marks the onset of Jurassic palynomorphs (Fig. 1). Another drastic negative C isotope excursion occurs at the top of the Koessen Formation concomitant with the disappearance of Triassic macrofauna, and both isotopic events can be recognized in boundary sections in England, Greenland and Nevada. The Triassic/Jurassic boundary (TJB) beds of the Karwendel Syncline (northern Tyrol) are well exposed at many places, easily correlatable by palynology (Fig. 1) and show a thicker (about 20 m), lithologically different, marl-dominated Tiefengraben Member with reddish clays ("Schattwald beds" auct.) at the base. They are richer and more diverse in micro- and macrofauna, and they contain an ammonite horizon around 7 m above the Koessen top with a new psiloceratid ammonite unknown from Europe and the Tethys realm. Based on its less intended suture line, the involute conch (umbilical width 40%) and juvenile tubercles (Knötchenstadium) the species is close to the South American earliest psiloceratid P. tilmanni but differs in a subtriangular cross-section. The new "Liassic" ammonite layer corresponds closely to the turnover in the Forminifera and to the onset of "Jurassic" ostracods (e.g. Cytherelloidea pulchella) as well as palynomorphs, with C. thiergatii as a first order correlation tool to marginal marine and continental basins. Bivalves in the basal Grenzmergel may bridge the present macrofaunal gap down to the Koessen Formation top but have still to be evaluated; a nannoplankton analysis is already under way. The investigated sections provide an important new insight in the nature of the physical and biological changes occurring around the boundary with rapidly changing palynomorph associations that point to several short-termed climatic oscillations. In which way they have affected the environmental conditions across the TJB and have controlled the stratigraphic ranges of biomarkers will be an important issue of the ongoing studies. Irrespective of any extinction scenario we see the fossil and geochemical record of the Karwendel Syncline as a major improvement of our knowledge of this time interval and as justified reason to introduce there a section as GSSP candidate for the Triassic/Jurassic boundary.

10

The ammonite faunas of the Callovian/Oxfordian boundary interval in Europe and their relevance to the establishment of an Oxfordian GSSP

Melendez G., Page K., Wright J., Atrops F.

Volumina Jurassica

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2006

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Vol. 4, no. 1

185-185

EN

The latest Callovian and Early Oxfordian represent one of the most dynamic intervals in the history of Jurassic Ammonoidea and is characterized by one of the highest levels of mixing of Boreal, Submediterranean and even Mediterranean faunas. In particular the massive expansion of Boreal Cardioceratidae from their original “home” in Arctic areas as far south as South East France, brings them into contact with Mediterranean-style faunas rich in Phylloceratidae. This so-called “Boreal Spread” (after J. H. Callomon) provides the framework within which high-resolution inter-bioprovincial correlations are possible and hence the context for a sucessful GSSP designation for the base of the Oxfordian Stage within Europe (and hence the beginning of the Upper Jurassic). Associated with the Cardioceratidae, however, is a great variety of Perisphinctina, including Aspidoceratidae, Periphinctidae, Grossouvridae and rarer Pachyceratidae as well as frequent Hecticoceratidae and rarer Phylloceratidae. The latter groups are much more abundant in southern areas (Tethyan Realm), but the Aspidoceratidae do persist well into the Boreal Realm. Crucially, several groups of the Perisphinctina persist beyond Europe and therefore provide tantalising indications that a truly global correlation of any GSSP established in Europe will ultimately be possible. The current paper will review the stratigraphical, taxonomic and palaeobiogeographical context and significance of the trans Callovian/Oxfordian boundary faunas within Europe, building on recent results from the UK and France. Conclusions will be drawn concerning the appropriate – or convenient – level at which the place the Callovian-Oxfordian in Europe and its potential interpretation elsewhere. Such conclusions are highly relevant to the eventual establishment of an Oxfordian GSSP.

11

Pliensbachian/Toarcian boundary: the proposed GSSP of Peniche (Portugal)

Elmi S.

Volumina Jurassica

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2006

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Vol. 4, no. 1

5-16

EN

The Peniche section (Portugal) is cosidered as a potential stratotype (GSSP) for the Pliensbachian- Toarcian boundary and it is analysed on the background of the available data on the ammonite successions from other Tethyan and NW European areas.

12

Jurassic Global Stratotype Section and Points (GSSPs) – a potential serial World Heritage Site?

Page K., Melendez G., Henriques M.

Volumina Jurassica

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2006

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Vol. 4, no. 1

253-253

EN

The Operation Guidelines for the World Heritage Convention include the following criteria for the selection of natural heritage sites, which states that they should: "…be outstanding examples representing major stages of Earth's history, including the record of life, significant ongoing geological processes in the development of land forms, or significant geomorphic or physiographic features" [Criteria a (i)]; "The sites listed in a (i) should contain all or most of the key interrelated and interdependent elements in their natural relationships…" [Criteria b (i)]; "The site described in paragraph (a) should have a management plan…" [Criteria b (v)]; "A site described in paragraph (a) should have adequate long-term legislative, regulatory, institutional or traditional protection..." [Criteria b (vi)]. Global Stratotype Sections and Points (GSSPs) represent, by definition, the most stratigraphically complete and globally important stage-boundary sections known. They therefore fully satisfy the World Heritage criterion a (i). Crucially, their identification and ratification is regulated globally by the International Union of Geological Sciences (IUGS) which also advises UNESCO on the selection of World Heritage Sites for geological features - such a ratification can be taken as confirmation of global significance in more than just a technical or scientific sense. In addition, as part of the GSSP selection process aspects of the site's conservation status and safeguard for future study are also taken into consideration, Criterion b (vi) and be satisfied, if not b (v) as well. The proposal of any single GSSP in isolation as a World Heritage site is unlikely succeed, however, as individually such sites may lack a broader context. Combining a suite of GSSPs sites in a "serial" World Heritage site proposal - a well established approach in other contexts - is however, conceptually much more likely to succeed. In particular a proposal incorporating all the applicable GSSPs for a single system could certainly satisfy Criterion b (i), especially as all key interrelated and interdependent elements would then be included, i.e. all component stages of that system. Such a proposal could be an ultimately goal for the ISJS, as a celebration of decades of intensive work by many colleagues from many countries. Such a project would require a high degree of international agreement and already five countries are implicated in the process: Portugal, Spain, England, Scotland and France. Nevertheless, the close working relationships between specialists in different nations established through the Working Groups of the Subcommission can offer a marvellous opportunity for such collaboration.

13

Integrated stratigraphical study of the candidate Oxfordian Global Stratotype Section and Point (GSSP) at Redcliff Point, Weymouth, Dorset, UK

Page K., Melendez G., Hart M., Price G., Wright J., Bown P., Bello J.

Volumina Jurassica

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2006

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Vol. 4, no. 1

200-201

EN

Redcliff Point near Weymouth, Dorset (SW England) exposes one of Europe’s most complete Callovian-Oxfordian boundary sequences and has been the subject of a rigorous multidisciplinary assessment. The boundary sequence lies entirely within the clay facies of the Oxford Clay Formation, the relatively high carbonate content of which facilitates the excellent preservation of both macro- and microfaunas (and floras) as well as geochemical information. Ammonites, in particular, are conspicuous, and partly retain an aragonitic shell. By convention, the stage boundary is drawn at the first occurrence of the genus Cardioceras, which has been interpreted as corresponding to the transition between “Quenstedtoceras” paucicostatum (Lang) and Cardioceras ex gr. scarburgense (Young and Bird), specifically at the first occurrence of C. woodhamense Arkell sensu Callomon (non Marchand). This transition is well seen at Redcliff and provides the primary means through which the boundary can be correlated. Associated Perisphinctina (including Peltoceras, Alligaticeras, Properisphinctes and Euaspidoceras) provide additional biostratigraphical information. Other macrofossil groups show less discernible changes, although the end of the Callovian in England marks the local, virtual disappearance of Boreal cylindroteuthid belemnites with the persistence of Tethyan hibolithids into the Early Oxfordian. Isotopic studies of recovered belemnites record important information on carbon and strontium isotopes and provide new, high resolution data for the refinement of the global curves. The isotope data are also consistent with continuous sedimentation across the boundary. Foraminiferal assemblages are dominated by poorly preserved epistominids. Planktonic Foraminifera are recorded, mainly as pyrite steinkerns. This makes identification difficult although a flood close to the boundary appears to be Globuligerina oxfordiana. Other planktonic taxa are present, including one species that may be new. Nannofloras are well preserved, common to abundant and dominated by Watznaueria britannica with conspicuous Zeugrhabdotus erectus, podorhabdids and Stephanolithion bigotii. The presence of Stephanolithion bigotii maximum throughout, places the samples within the NJ14 biozone. Ostrocoda and holothurian spicules are also recorded. These results are synthesised to provide a multidisciplinary, integrated review of the suitability of Redcliff Point for the definition of an Oxfordian GSSP. Correlations with the French candidate site in Savournon, Haute-Provence are discussed and proposals made for formally establishing a GSSP for the base of the Oxfordian Stage in Europe.