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The microcrinoid taxonomy, biostratigraphy and correlation of the upper Fredericksburg and lower Washita groups (Cretaceous, middle Albian to lower Cenomanian) of northern Texas and southern Oklahoma, USA

Gale Andrew Scott, Rashall Jenny Marie, Kennedy William James, Holterhoff Frank Koch

Acta Geologica Polonica

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2021

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Vol. 71, no. 1

1--52

EN

The stratigraphy of the upper Fredericksburg and lower Washita groups of northern Texas and southern Oklahoma is described, and biostratigraphical correlation within the region, and further afield, using micro-crinoids, ammonites, planktonic foraminiferans and inoceramid bivalves is summarised. The taxonomy of the roveacrind microcrinoids is revised by the senior author, and a new genus, Peckicrinus, is described, with the type species Poecilocrinus porcatus (Peck, 1943). New species include Roveacrinus proteus sp. nov., R. morganae sp. nov., Plotocrinus reidi sp. nov., Pl. molineuxae sp. nov., Pl. rashallae sp. nov. and Styracocrinus thomasae sp. nov. New formae of the genus Poecilocrinus Peck, 1943 are Po. dispandus forma floriformis nov. and Po. dispandus forma discus nov. New formae of the genus Euglyphocrinus Gale, 2019 are E. pyramidalis(Peck, 1943) forma pyramidalis nov., E. pyramidalis forma radix nov. and E. pyramidalis forma pentaspinusnov. The genera Plotocrinus Peck, 1943, Poecilocrinus and Roveacrinus Douglas, 1908 form a branching phylogenetic lineage extending from the middle Albian into the lower Cenomanian, showing rapid speciation, upon which a new roveacrinid zonation for the middle and upper Albian (zones AlR1-12) is largely based. Outside Texas and Oklahoma, zone AlR1 is recorded from the lower middle Albian of Aube (southeastern France) and zones AlR11-CeR2 from the Agadir Basin in Morocco and central Tunisia. It is likely that the zonation will be widely applicable to the middle and upper Albian and lower Cenomanian successions of many other regions.

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Stratigraphy of the Albian-Cenomanian boundary interval in the Agadir Basin, Morocco: ammonites, microcrinoids, planktonic foraminifera

Gale Andrew Scott, Kennedy William James, Petrizzo Maria Rose

Acta Geologica Polonica

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2021

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Vol. 71, no. 4

453--480

EN

The uppermost Albian and lowermost Cenomanian succession at Abouda Plage, north of Agadir, in the Agadir Basin, western Morocco, is described in detail, and ammonites, microcrinoids and planktonic foraminifera are recorded and illustrated. The lower part of the Aït Lamine Formation yields ammonites indicative of the Pervinquieria (Subschloenbachia) rostrata and P. (S.) perinflata ammonite zones, and the Thalmanninella appenninica planktonic foraminiferan Zone. The base of the Cenomanian is identified at 42.2 m above the base of the Aït Lamine Formation, based on the lowest occurrence of the planktonic foraminiferan Thalmanninella globotruncanoides Sigal, 1948. Lower Cenomanian ammonites of the Graysonites adkinsi Zone enter 3 m higher in the succession. Microcrinoid zones AlR11 and AlR12 are identified in the Upper Albian, and the base of the CeR1 Zone coincides with the lowest occurrence of Cenomanian ammonites. The ammonite and microcrinoid occurrences and detailed distributions are very similar to those found in north central Texas, which, in the Cenomanian, was 5,300 km to the west. The new records suggest that the G. adkinsi Zone is equivalent to the uppermost (Lower Cenomanian) part of the Pleurohoplites briacensis Zone of the Global Stratotype Section for the base of the Cenomanian stage. An hiatus, of global extent, immediately underlies the base of the G. adkinsi Zone and is represented in the Agadir Basin by an erosion surface containing bored and encrusted hiatus concretions.

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On some Turonian and Coniacian ammonites from central Colombia

Kennedy William James

Acta Geologica Polonica

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2021

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Vol. 71, no. 3

259--285

EN

The rich collections of Turonian and Coniacian ammonites from Colombia, housed in the University of California Museum of Paleontology, Berkeley, are described, with 20 species recognized, referred to the genera Reymenticoceras Kennedy, 2018, Vascoceras Choffat, 1898, Fagesia Pervinquière, 1907, Wrightoceras Reyment, 1954a, Subprionocyclus Shimizu, 1932, Subprionotropis Basse, 1951, Prionocycloceras Spath, 1926, Barroisiceras de Grossouvre, 1894, Forresteria Reeside, 1932, Niceforoceras Basse, 1948, Peroniceras de Grossouvre, 1894, Gauthiericeras de Grossouvre, 1894, Protexanites Matsumoto, 1955, and Metaptychoceras Spath, 1926. One species, Reymenticoceras ornatum, is new. Most of the species described can be assigned to the substages and ammonite zones recognized in Western Europe.

4

Upper Albian, Cenomanian and Upper Turonian ammonite faunas from the Fahdène Formation of Central Tunisia and correlatives in northern Algeria

Kennedy William James

Acta Geologica Polonica

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2020

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Vol. 70, no. 2

147--272

EN

Over 130 species are documented from the Upper Albian, Cenomanian and Upper Turonian Fahdène Formation and correlatives in Central Tunisia and northern Algeria, based on material described by Henri Coquand (1852, 1854, 1862, 1880), Léon Pervinquière (1907, 1910), Georges Dubourdieu (1953), Jacques Sornay (1955), and new collections. The material consists predominantly of limonitic nuclei, together with adults of micromorphs. There is no continuous record, and a series of faunas are recognised that can be correlated with the zonation developed in Western Europe. These are the Upper Albian Ostlingoceras puzosianum fauna, Lower Cenomanian Neostlingoceras carcitanense and Mariella (Mariella) harchaensis faunas, the upper Lower to lower Middle Cenomanian Turrilites scheuchzerianus fauna, Middle Cenomanian Calycoceras (Newboldiceras) asiaticum fauna, Upper Cenomanian Eucalycoceras pentagonum fauna, and the Upper Turonian Subprionocyclus neptuni fauna. Two new micromorph genera are described, Coquandiceras of the Mantelliceratinae and Cryptoturrilites of the Turrilitinae. Most of the taxa present have a cosmopolitan distribution, with a minority of Boreal, North American and endemic taxa.