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Upper Cretaceous of the Barranca (Navarra, northern Spain); integrated litho-, bio- and event stratigraphy.Part 2, Campanian and Maastrichtian

Kuchler T.

Acta Geologica Polonica

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2000

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Vol. 50, no. 4

441-499

EN

Campanian to Lower Maastrichtian strata of the eastern Barranca (Navarra, northern Spain), based on 11 exposures near Irurzun, were investigated in detail and correlated with coeval strata of the western Barranca and the Oroz-Betelu Massif (Navarra). The Sarasate Formation exposed in the Barranca in divided into ten members. Deposition was influenced by uplift of the Anoz-Ollo salt structure during the latest Santonian and Early Campanian. The Campanian-Maastrichtian of Navarra is characterised by thick and relatively complete successions containing biostratigraphically significant fossil groups (ammonites, inoceramids, echinoids). Detailed bed-by-bed collecting has enabled the establishment of an integrated zonal scheme with potential for interbasinal correlation. In addition to local peak, partial range and assemblage zones, based on echinoids and ammonite-echinoid assemblages, an ammonite zonation, based on an unnamed interval and the following 10 partial range (PRZ) and assemblage zones (AZ) of Scaphites hippocrepis III, S. hippocrepis III/Menabites spp., Hoplitoplacenticeras marroti, Trachyscaphites spiniger, Pseudoxybeloceras phaleratum, Nostoceras (Bostrychoceras) polyplocum, Trachyscaphites pulcherrimus, N. (didymoceras) archiacianum, N. (Nostoceras) hyatti and Pachydiscus neubergicus/Pachydiscus epiplectus, is presented. The ammonite zonation markedly refines both the existing regional and the so-called European standard zonal schemes. Correlation with other Spanish areas (Cantabria, Burgos and Guipuzcoa), the Aquitaine (France), Westphalia and Lower Saxony (Germany) and the Vistula valley (Poland) is discussed. Twelve of the recognised bio-events, characterised by mass-occurrences of irregular echinoids and of monospecific, or taxonomically more variable, mostly heteromorph ammonite assemblages, are significant for regional correlation. Three Offaster maxima are of interbasinal importance as they can be correlated to Germany, Great Britain and Northern Ireland. The origin of these bio-events is closely related to the transgressive and regressive pulses recognised in Navarra, of which the pomeli Transgression I and the hippocrepis, subglobosa and polyplocum regressions are the most pronounced. The tectonic phase at the Santonian/Campanian boundary is related to the Wernigerode Phase. The onset of the second phase is placed in the lower Upper Campanian marotti Zone, the onset of a third phase (UCTE) in theUpper Campanian polyplocum Zone.

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Scaphites hippocrepis (DEKAY) IV, a new chronological subspecies from the Lower - Upper Campanian (Upper Cretaceous) boundary interval of northern Spain

Kuchler T.

Acta Geologica Polonica

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2000

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Vol. 50, no. 1

161-167

EN

A fourth chronological subspecies of Scaphites hippocrepis (DeKay), called S. hippocrepis IV, is described from the highest Lower Campanian and lower Upper Campanian of Navarra, northern Spain. It is the stratigraphically highest representative of the hippocrepis lineage, characterized by strong conical to massive umbilical tubercles, which number three to five in microconchs and five in macroconchs

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Upper Cretaceous of the Barranca (Navarra, northern Spain); integrated litho-, bio- and even stratigraphy. 1, Cenomanian through Santonian

Kuchler T.

Acta Geologica Polonica

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1998

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Vol. 48, no. 2

157-236

EN

Fossiliferous Upper Cenomanian to Lower Maastrichtian strata in Navarra, northern Spain, particularly in the eastern Barranca, were investigated in terms of litostratigraphy, macrofossil biostratigraphy and event stratigraphy. Extensive bed-by bed-collections of ammonites, inoceramids, and echinoids allow the establishment of combined standard zonal schemes of inter-regional significance. Data on geochronological boundaries, macrofossil distribution, the succession of events and the inter-relations between bioevents, eustato-events and tectonic movements in northern Spain are presented. The Upper Cenomanian - Turonian successions of the Barranca sections (Arardi, Izurdiaga, Satrustegui) and of the Estella area (Ganuza, Ollogoyen), differ considerably in both lithofacies and thickness and periodically, in faunal composition, as a result of their palaeogeographical positions within an stable outer shelf and an unstable mit-shelf, respectively. The Ganuza/Ollogoyen standard section is revised. In the context of the established event stratigraphical scheme, discrepancies in previously applied ammonite zonation are pointed out and discussed in terms of their regional relevance. The expanded and relatively complete Turonian of the Estella area is subdivided into an unnamed interval devoid of ammonites (Upper Cenomanian Metoicoceras geslinianum Zone to the mid-Lower Turonian), six ammonite zones and an inoceramid/ammonite assemblage zone. The upper Lower Turonian Kamerunoceras ganuzai/Mammites nodosoides Zone is succeeded by the Middle Turonian zones of K. turoniense, Romaniceras kallesi, R. ornatissimum and R. deverianum; and the Upper Turonian Subprionocyclus neptuni and Cremnoceramus waltersdorfensis/ Prionocyclus germari zones. The Lower Turonian zonal scheme given by WIEDMANN (1979a) for the Estella area is shown to be impracticable, and neither Lower Turonian Choffaticeras quaasi Zone sensu SANTAMARIA (1992) nor a Watinoceras coloradoense Zone sensu LAMOLDA & al. (1989) can be recognized. On the other hand, the refined French Middle Turonian ammonite zonation of AMEDRO & al. (1982) is readily applicable, while the application of a Collignoniceras woolgari Zone is hardly possible. The base of the Middle Turonian has been placed at the FAD of K. turoniense, at a level stratigraphically lower (upper Lower Turonian) than the one recently accepted. C. woollgari is rare and appears no lower than the ornatissimum Zone. The base of the Upper Turonian is placed at the FAD of Subprionocyclus neptuni. Romaniceras deverianum appears considerably lower than the former, but has its main occurrence in the neptuni Zone, ranging up to overlap with Prionocyclus germari. The Barranca succession is condensed and includes hiati from the Upper Cenomanian Neocardioceras juddii Zone to the upper ganuzai/ nodosoides Zone; between the Middle Turonian kallesi and ornatissimum zones; and in the lower Upper Turonian neptuni Zone. Twelve bio-events that are significant for regional and inter-regional correlations are differentiated and dated: the Mytiloides kossmati, ganuzai, reveliereanus, turoniense/hercynicus, kallesi/ornatissimum, Scaphites geinitzii, Subprionocyclus I, Micraster ex gr. normanniaecortestudinarium, Subprionocyclus II events. Most of these events are time-equivalents of events already recognised by ERNST & al. (1983) in Germany. The biostratigraphic framework permits a dating and correlation of the major tectono-sedimentary and eustato-events, namely the Cenomanian-Turonian Boundary Event (CTBE), the Middle Turonian Event (MTE) and Lower Upper Turonian Event (LUTE). The calcareous Coniacian - Santonian succession of the eastern Barranca (Izurdiaga, Ecay and Zuazu sections), is divided into Lower Izurdiaga, Zuazu and Upper Izurdiaga formations, and into numerous component members. The succession is rich in echinoids, and is biostratigraphically important because of the cooccurrence of inoceramids and ammonites. The Coniacian ammonite assemblages show affinities to those of the French type region and to the largely endemic ones of the Spanish standard sections in Burgos. The data obtained permit a confident correlation of the biostratigraphic frameworks of these two areas for the first time. In contrast to the widespread basal Coniacian hiatus, the Barranca succession at this level is locally relatively complete. The lower Coniacian Cremnoceramus rotundatus, Forresteria petrocoriensis and Peroniceras subtricarinatum zones, the Middle Coniacian Gauthiericeras margae Zone and the lower Upper Coniacian Protexanites bourgeoisi Zone are recognized. In marginal sections, the bourgeoisi Zone is followed by an hiatus which comprises the late Upper Coniacian Magadiceramus subquadratus and the Lower Santonian Cladoceramus undulatoplicatus inoceramid zones recognized in the continuous section of the western Barranca. By means of ammonites, the Santonian at Olazagutia is divided into an unnamed interval devoid of ammonites; the middle Coniacian Texanites quiquenodosus and the Upper Santonian Jouaniceras hispanicum/Scalarites cingulatum Zone. This scheme has affinities with the zonation applied by KENNEDY & al. (1995) in the Corbieres, France. In addition to a sequence of regionally important events and marker-beds, some events, namely the Didymotis II, Micraster ex gr. cortestudinarium andCladoceramus undulatoplicatus events, are of inter-basinal importance.