Cretaceous Stage Boundaries — Proposals

AbstractA preliminary summary of the lower Visean to uppermost Moscovian (Carboniferous) conodont succession and biostratigraphy of the Dianzishang section in Zhenning, Guizhou, South China is presented. Eleven conodont zones, in ascending order, can be recognized:Gnathodus praebilineatus,Gnathodus bilineatus,Lochriea ziegleri,Declinognathodus noduliferus,Neognathodus symmetricus, ‘Streptognathodus’expansus(primitive form), ‘Streptognathodus’expansus,Mesogondolella donbassica – Mesogondolella clarki,Idiognathodus podolskensis,Swadelinafauna andIdiognathodus swadeizones. The first occurrences ofLochriea ziegleriat the base of the Serpukhovian Stage,Declinognathodus noduliferus noduliferusat the base of the Bashkirian Stage and ‘Streptognathodus’expansusat the base of the Moscovian Stage are recognized. The definitions of these stage boundaries, as well as that of the base of the Kasimovian Stage are discussed. Correlations with the Naqing section in South China, Russian and North American sections, as well as other important sections in the world, are considered.

Download Full-text

Biostratigraphical criteria for the recognition of the Coniacian to Maastrichtian stage boundaries in the Chalk of north-west Europe, with particular reference to southern England.

Bulletin of the Geological Society of Denmark ◽

10.37570/bgsd-1984-33-03 ◽

1984 ◽

Vol 33 ◽

pp. 31-39

Author(s):

H. W. Bailey ◽

A. S. Gale ◽

R. N. Mortimore ◽

A. Swiecicki ◽

C. J. Wood

Keyword(s):

Critical Assessment ◽

Basal Part ◽

Paris Basin ◽

Northern Germany ◽

North West ◽

Entry Level ◽

Southern England ◽

Standard Section ◽

Stage Boundaries

The biostratigraphical criteria for the recognition of Coniacian to Maastrichtian stage boundaries in the English Chalk, published in the Abstracts to the Copenhagen Symposium on Cretaceous Stage Boundaries 1983, are reviewed in the light of the discussion at the Symposium and the final recommendations. Particular attention is given to problems relating to the base of the Coniacian and Santonian Stages. A critical assessment is made of criteria used by French workers for recognising the base of the Senonian Stage in the Anglo-Paris Basin. Benthonic Foraminifera used to identify the base of the Senonian are shown to have discrepant ranges in Kent compared with Sussex and Senonian stratotype. The nannofossil Marthasterites furcatus first appears below the level of acme-occurrence of ammonites of the Late Turonian Subprionocyclus neptuni Zone in southern England, and cannot therefore be used as a marker to identify the base of the Coniacian in the Anglo-Paris Basin. Extended comment is made on the biostratigraphy of the successions in southern England and northern Germany across the Coniacian - Santonian boundary, and it is suggested that the Upper Coniacian Micraster bucaillei/Gonioteuthis praewestfalica Zone of the German Lligerdorf standard section should be re-assigned to the basal part of the Santonian. The base of the Campanian Stage in southern England is arbitrarily taken at the evolutionary first appearance of Bolivinoides culverensis, a level coincident with the top of the local Uintacrinus anglicus Zone, rather than at the extinction-level of Marsupites and/or entry of Gonioteuthis granulataquadrata lower in the succession. The entry of the nannofossil Broinsonia parca, widely taken as a criterion for recognising the base of the Campanian Stage, is shown to occur at an horizon well above the entry-level of B. culverensis.

Download Full-text

Phanerozoic Chronostratigraphy: Top-Down Instead of Bottom-Up Boundary Definitions

Proceedings ◽

10.3390/iecg2019-06199 ◽

2019 ◽

Vol 24 (1) ◽

pp. 26

Author(s):

Spencer G. Lucas

Keyword(s):

Top Down ◽

Bottom Up ◽

Single Set ◽

Stage Boundaries

The GSSP method defines stage bases, and, where proximate, equates them to the bases of larger chronostratigraphic units. The Phanerozoic and its subdivisions above the stage level thus are only successively larger “pigeonholes” within which to bin stages. This reductionism trivializes chronostratigraphic boundaries larger than stage boundaries. A single set of standard global stages is an unworkable abstraction that should be abandoned because no stage can be correlated globally because of facies changes, taphonomic biases, and/or provincialism. Stratigraphers should return to a top-down chronostratigraphy that defines chronostratigraphic units larger than stages by significant natural events that can be correlated globally.

Download Full-text

Stage boundaries of the Triassic in Northeast Asia

Stratigraphy and Geological Correlation ◽

10.1134/s0869593809020063 ◽

2009 ◽

Vol 17 (2) ◽

pp. 173-191 ◽

Cited By ~ 7

Author(s):

A. G. Konstantinov ◽

T. V. Klets

Keyword(s):

Northeast Asia ◽

Stage Boundaries

Download Full-text

Integrated biostratigraphy of the Santonian through Maastrichtian (Upper Cretaceous) of extra-Carpathian Poland

Acta Geologica Polonica ◽

10.1515/agp-2016-0016 ◽

2016 ◽

Vol 66 (3) ◽

pp. 321-358 ◽

Cited By ~ 15

Author(s):

Ireneusz Walaszczyk ◽

Zofia Dubicka ◽

Danuta Olszewska-Nejbert ◽

Zbigniew Remin

Keyword(s):

Upper Cretaceous ◽

Entire Interval ◽

Benthic Foraminifers ◽

Southern Poland ◽

South Eastern ◽

Vistula River ◽

Composite Section ◽

First Occurrence ◽

Western Ukraine ◽

Stage Boundaries

AbstractThe biostratigraphic importance, current zonations, and potential for the recognition of the standard chronostratigraphic boundaries of five palaeontological groups (benthic foraminifers, ammonites, belemnites, inoceramid bivalves and echinoids), critical for the stratigraphy of the Santonian through Maastrichtian (Upper Cretaceous) of extra-Carpathian Poland, are presented and discussed. The summary is based on recent studies in selected sections of southern Poland (Nida Synclinorium; Puławy Trough including the Middle Vistula River composite section; and Mielnik and Kornica sections of south-eastern Mazury-Podlasie Homocline) and of western Ukraine (Dubivtsi). The new zonation based on benthic forams is presented for the entire interval studied. Zonations for ammonites, belemnites and inoceramid bivalves are compiled. All stage boundaries, as currently defined or understood, may easily be constrained or precisely located with the groups discussed: the base of the Santonian with the First Occurrence (FO) of the inoceramid Cladoceramus undulatoplicatus; the base of the Campanian with the Last Occurrence (LO) of the crinoid Marsupites testudinarius and approximated by the range of the foraminifer Stensioeina pommerana; and the base of the Maastrichtian approximated by the FO of the inoceramid bivalve Endocostea typica and the FO of the belemnite Belemnella vistulensis. The positions of substage boundaries, as currently understood, are constrained in terms of the groups discussed.

Download Full-text

Macrofossil magnetobiostratigraphy for the upper Santonian–lower Campanian interval in the Western Interior of North America: comparisons with European stage boundaries and planktonic foraminiferal zonal boundaries

Canadian Journal of Earth Sciences ◽

10.1139/e95-020 ◽

1995 ◽

Vol 32 (3) ◽

pp. 247-260 ◽

Cited By ~ 18

Author(s):

G. D. Leahy ◽

J. F. Lerbekmo

Keyword(s):

North America ◽

Planktonic Foraminifera ◽

Niobrara Formation ◽

Lower Campanian ◽

Stage Boundaries ◽

Ammonite Zones

Magnetostratigraphic samples were collected from the Milk River and Pakowki formations of southeastern Alberta to determine the polarity chron 34–33 r boundary. This boundary was located in the upper half of the Deadhorse Coulee Member, and is below the first local occurrence of the Western Interior ammonite Baculites obtusus. Comparison with the laterally equivalent Eagle Sandstone of Montana and Niobrara Formation of Colorado indicates that the 34–33 r contact is within either the Baculites sp. (smooth) or Baculites sp. (weak flank ribs) ammonite zone in the Western Interior of North America. Direct correlation of the Desmoscaphites erdmanni through Baculites asperiformis Western Interior ammonite zones with magnetobiostratigraphic sections of the upper Santonian–lower Campanian stages in Europe suggests that (i) the Santonian–Campanian boundary as defined in Europe is within the lower Baculites obtusus Zone and (ii) the Western Interior appearance of some ammonites and crinoids (Scaphites hippocrepis, Trachyscaphites spiniger, Marsupites, Uintacrinus) is profoundly time transgressive relative to the appearance of these same species in Europe. The date of 84 Ma for the Santonian–Campanian boundary is too old, and a date of around 80 Ma may be more accurate. The Santonian–Campanian boundary defined by ammonites, crinoids, and belemnites in Europe is within the lower part of chron 33 r, and is younger than the Santonian–Campanian boundary as determined by planktonic foraminifera at Gubbio, Italy.

Download Full-text

Arabian Plate sequence stratigraphy: Potential implications for global chronostratigraphy

GeoArabia ◽

10.2113/geoarabia1204101 ◽

2007 ◽

Vol 12 (4) ◽

pp. 101-130 ◽

Cited By ~ 10

Author(s):

Michael D. Simmons ◽

Peter R. Sharland ◽

David M. Casey ◽

Roger B. Davies ◽

Owen E. Sutcliffe

Keyword(s):

Sequence Stratigraphy ◽

Bedding Plane ◽

Arabian Plate ◽

Third Order ◽

Level Change ◽

Stratotype Section ◽

Sequence Boundaries ◽

The 19Th Century ◽

Fundamental Units ◽

Stage Boundaries

ABSTRACT The ability to recognise and correlate third-order depositional sequences across Arabia and between Arabia and other plates indicates that these sequences are driven by synchronous eustatic sea-level change. This is of value in providing guidance for the definitions of stages, which are the fundamental units of chronostratigraphy. Each Phanerozoic stage requires a Global Stratotype Section and Point (GSSP), which is a location and specific bedding plane where the base of each stage is defined. This definition is tied to an event in the rock record useful for correlation. Progress in defining GSSPs has been delayed because of difficulties in choosing the most appropriate event and section to relate to a definition. It is recommended here that stage boundaries be related to correlative conformities of sequence boundaries. This closely links chronostratigraphy with sequence stratigraphy and honours the original concepts upon which many stages were first described in the 19th Century.

Download Full-text