The Meishan Section of Changxing County, Zhejiang Province, China and the base of its Bed 27c,in which Hindeodus parvus first occurs, are recommended as the GSSP of Permian-Triassic boundary (PTB).The present paper in...The Meishan Section of Changxing County, Zhejiang Province, China and the base of its Bed 27c,in which Hindeodus parvus first occurs, are recommended as the GSSP of Permian-Triassic boundary (PTB).The present paper introduces a description of the section. Biostratigraphic correlation with other famous sections shows the completeness of this section and justifies choice of H. Parvus as the index fossil. Chemostratigraphic investigation provides the δ￣13C excursion and the moderate but inconsistent Ir spike as auxiliary symbols for the PTB. This boundary is closely related to transgression,anoxia,volcanism,mass extinction and possible impact events which can be correlated with those in South China and other parts of the world .展开更多
Through a detailed study of sequence boundaries, it is concluded that sequence stratigraphy is an independent regional and transitional stratigraphic system between local lithostratigraphy and global chronostratigraph...Through a detailed study of sequence boundaries, it is concluded that sequence stratigraphy is an independent regional and transitional stratigraphic system between local lithostratigraphy and global chronostratigraphy. Therefore, a new tripartite stratigraphic classification scheme has been proposed. By combining organically the concept of sequence boundaries with the GSSP, it is suggested that the GSSP should be chosen in a conformale portion of a related sequence boundary, and the boundary established in light of this concept is defined as the Best Natural Boundary (BNB). The definition of the BNB points out the working area and stratigraphic level for the GSSP. By referring to a case study of the Permian Guadalupian/Lopingian boundary, the concept of the BNB has been elaborated in detail, and it is proposed that the BNB of the Guadalupian and the Lopingian lies between the Mesogondolella granti Zone and the Ctarkina postbitteri Zone, which is also the sequence chronostratigraphic boundary between the Transpecos composite sequence (chronozone)and the UAA- 1 composite sequence (chronozone).展开更多
Following voting by the Kimmeridgian Working Group,the International Subcommission on Jurassic Stratigraphy and the International Commission on Stratigraphy,the Global Stratotype Section and Point(GSSP)for the base of...Following voting by the Kimmeridgian Working Group,the International Subcommission on Jurassic Stratigraphy and the International Commission on Stratigraphy,the Global Stratotype Section and Point(GSSP)for the base of the Kimmeridgian Stage(Jurassic System)was ratified by the executive of the International Union of Geological Sciences.The boundary is placed in the upper part of Bed 35 of the Staffin Shale Formation,1.25±0.01 m below the base of Bed 36 in block F6 in the foreshore at Flodigarry,Staffin Bay,Isle of Skye,Scotland.The coordinates for the middle part of the two adjacent sections(sections F6N and F6S)are 57°39'39.5″N,6°14'43.9″W and 57°39'40.5″N,6°14'45″W;UK National Grid Scheme NG 46877139 and NG 46877142±5 m.This stratigraphic point coincides with the appearance over a short stratigraphic interval of several new ammonite taxa that delineate the base of the Subboreal ammonite Baylei Zone,the base of the Densicostata Subzone marked by the base of the flodigarriensis horizon,and,independently,the base of the Boreal ammonite Bauhini Zone.The main advantages of this locality are:the presence of a dual ammonite zonation marked by two extensively studied,well-preserved and very abundant groups of ammonites,and their preservation within a continuous section of~120 m of open marine,fossiliferous,thermally immature mudrocks with no evidence of condensation or stratigraphic gaps.Dinoflagellate cysts,magnetostratigraphy and stable isotope data from the same section provide secondary markers.The stratigraphic point is located 0.17–0.65 m below the boundary interval between the dinoflagellate cyst zones DSJ 26 and DSJ 27(equivalent to the boundary between subzones c and d of the Scriniodinium crystallinum(=Scr)Zone).展开更多
Following votes by the Hauterivian Working Group,the Cretaceous Subcommission and the International Commission on Stratigraphy,in December 2019 the Executive Committee of the International Union of Geological Sciences...Following votes by the Hauterivian Working Group,the Cretaceous Subcommission and the International Commission on Stratigraphy,in December 2019 the Executive Committee of the International Union of Geological Sciences unanimously approved the proposal that the Global Stratotype Section and Point(GSSP)for the base of the Hauterivian Stage of the Lower Cretaceous be placed at the base of bed no 189 of the La Charce section,Drôme,southeast France(Vocontian Basin).This level is marked by the first appearance of the ammonite genus Acanthodiscus,which defines the base of the Acanthodiscus radiatus ammonite Zone.Complementary data include 13 ammonite and nannofossil events,and magnetostratigraphic and carbon isotope events.展开更多
The Global Stratotype Section and Point(GSSP)for the base of the Capitanian Stage was proposed in 1999 and defined by the first appearance datum(FAD)of the conodont Jinogondolella postserrata within the lineage J.aser...The Global Stratotype Section and Point(GSSP)for the base of the Capitanian Stage was proposed in 1999 and defined by the first appearance datum(FAD)of the conodont Jinogondolella postserrata within the lineage J.aserrata→J.postserrata→J.shannoni at Nipple Hill in West Texas,USA.Despite its widespread recognition for more than two decades,the official GSSP paper was not published,nor have its index conodont fossils been properly documented.At Nipple Hill,only the uppermost 0.5 m of the Pinery Member belongs to the Capitanian Stage.J.postserrata first appears at 19.8 m above the base of the auxiliary Frijole section.Based on U-Pb CA-ID-TIMS geochronology of ash beds from the GSSP area,the base of the Capitanian Stage has been constrained at 264.28±0.16Ma.Magnetostratigraphy suggests that the Illawarra Reversal is located slightly below the base of the Capitanian Stage.Strontium isotope chemostratigraphy generally shows a continuous decline in the 87Sr/86Sr ratio throughout the Capitanian in the GSSP area,but all ratios are higher than the Capitanian minimum of~0.7068.δ^(13)Ccarb profile shows no distinct excursion around the Wordian/Capitanian boundary interval.Detailed correlation suggests that the middle-upper part of the fusuline-based Midian Stage correlates with the Capitanian Stage.展开更多
Following votes by the Barremian Working Group,the International Subcommission on Cretaceous Stratigraphy and the International Commission on Stratigraphy,the Executive Committee of the International Union of Geologic...Following votes by the Barremian Working Group,the International Subcommission on Cretaceous Stratigraphy and the International Commission on Stratigraphy,the Executive Committee of the International Union of Geological Sciences unanimously approved in March 2023 the Global Stratotype Section and Point(GSSP)for the Barremian Stage(Lower Cretaceous).The base of the Barremian Stage is defined at the base of bed 171 of the Río Argos section,near Caravaca(SE Spain)and correlated by the first appearance of the ammonite species Taveraidiscus hugii.This event falls within the NC5C calcareous nannofossil Subzone,the Lilliputianella semielongata planktonic foraminiferal Zone,and the Dorothia ouachensis benthic foraminiferal Zone.It roughly coincides with the beginning of a slightly negative trend interval in theδ^(13)C curve.Indirect calibration to the magnetostratigraphic scale suggests that the boundary falls in the lowermost part of polarity chron M3r.According to the astrochronological analysis,a time interval of 0.74 myr separates the beginning of the late Hauterivian Faraoni Episode from the base of the Barremian,which is dated at 125.77 MA.展开更多
The Calabrian Stage is now formally defined by the Global Boundary Stratotype Section and Point(GSSP)at Vrica,Calabria,Italy.This GSSP had previously defined the base of the Pleistocene Series.The Calabrian becomes th...The Calabrian Stage is now formally defined by the Global Boundary Stratotype Section and Point(GSSP)at Vrica,Calabria,Italy.This GSSP had previously defined the base of the Pleistocene Series.The Calabrian becomes the second stage of the Pleistocene Series and Quaternary System,following the Gelasian.The GSSP occurs at the base of the marine claystone conformably overlying sapropelic bed‘e’within Segment B in the Vrica section.This lithological level represents the primary marker for the recognition of the boundary,and is assigned an astronomical age of 1.80 Ma on the basis of sapropel calibration.It coincides with the transition from Marine Isotope Stage 65 to 64,and the underlying sapropel bed‘e’is assigned to the Mediterranean Precession-Related Sapropel layer 176.Secondary markers include calcareous plankton bioevents of widely distributed taxa.The boundary falls between the highest occurrence of Discoaster brouweri(below)and the lowest common occurrence of left-coiling Neogloboquadrina pachyderma(above),and below the lowest occurrences of medium-sized Gephyrocapsa(including G.oceanica)and Globigerinoides tenellus.The top of the Olduvai Subchron is identified c.8 m above the GSSP.Ratification of the Calabrian Stage effectively completes the Lower Pleistocene Subseries.展开更多
The steps and methods for the establishment of the global boundary stratotype section and point (GSSP) are summed up briefly as follows. (i) Select rock sequences of approximately the same age duration in a region, ma...The steps and methods for the establishment of the global boundary stratotype section and point (GSSP) are summed up briefly as follows. (i) Select rock sequences of approximately the same age duration in a region, make a thorough study of their properties or attributes in order to establish the high-resolution stratigraphic units reflecting the natural rhythms in Earth's history, and proceed by multidisciplinary comprehensive studies to reveal the relationship, including time-space relation and possible mutual causality, among the various stratigraphic units and the different natural rhythms established. (ii) Seek for the 'natural break' that represents the 'major natural changes in the historical development of the Earth' in shallow marine facies areas, which is frequently the third-order sequence boundaries. (iii) Trace from shallow marine facies areas toward the continental slope and bathyal areas to seek for a continuous depositional sequence that corresponds in time span to the 'natural break' of shallow marine facies areas. (iv) Seek for a horizon within the continuous depositional sequence that approximately coincides with the maximum regressive point in the 'natural break'. This horizon is commonly within a lowerstand systems tract (LST) or a shelf margin systems tract (SMST) of the relevant third-order sequence. (v) Seek immediately above this horizon of maximum marine regression for an organic radiation or explosion event closely related to the natural boundary, which is generally the first flooding surface (FFS) of the relevant third-order sequence. (vi) Select within the organic event deposits closely related to the FFS the base boundary of a fossil taxon with widest geographical range as the Leading Group biozone for designation of the stratigraphic boundary. (vii) Select from among the sections with continuous depositional sequence formed under similar sedimentary palaeogeographic background (in general continental slope or bathyal environments) the section which possesses the shortest distance between the base boundary of the Leading Group biozone and the immediately underlying FFS of the relevant third-order sequence as the global stratotype section. The first appearance datum (FAD) of the Leading Group biozone species in the section may be regarded as the ideal GSSP. The steps suggested above are a supplement and improvement of the currently used procedures and methods for establishing GSSP. The GSSP established by using the steps and methods suggested here would make the stratigraphic boundaries better reflect the 'major natural changes in the historical development of the Earth', more readily distinguishable and easily operable in recognition and correlation, and at the same time also make the designation of boundaries more objective.展开更多
文摘The Meishan Section of Changxing County, Zhejiang Province, China and the base of its Bed 27c,in which Hindeodus parvus first occurs, are recommended as the GSSP of Permian-Triassic boundary (PTB).The present paper introduces a description of the section. Biostratigraphic correlation with other famous sections shows the completeness of this section and justifies choice of H. Parvus as the index fossil. Chemostratigraphic investigation provides the δ￣13C excursion and the moderate but inconsistent Ir spike as auxiliary symbols for the PTB. This boundary is closely related to transgression,anoxia,volcanism,mass extinction and possible impact events which can be correlated with those in South China and other parts of the world .
文摘Through a detailed study of sequence boundaries, it is concluded that sequence stratigraphy is an independent regional and transitional stratigraphic system between local lithostratigraphy and global chronostratigraphy. Therefore, a new tripartite stratigraphic classification scheme has been proposed. By combining organically the concept of sequence boundaries with the GSSP, it is suggested that the GSSP should be chosen in a conformale portion of a related sequence boundary, and the boundary established in light of this concept is defined as the Best Natural Boundary (BNB). The definition of the BNB points out the working area and stratigraphic level for the GSSP. By referring to a case study of the Permian Guadalupian/Lopingian boundary, the concept of the BNB has been elaborated in detail, and it is proposed that the BNB of the Guadalupian and the Lopingian lies between the Mesogondolella granti Zone and the Ctarkina postbitteri Zone, which is also the sequence chronostratigraphic boundary between the Transpecos composite sequence (chronozone)and the UAA- 1 composite sequence (chronozone).
文摘Following voting by the Kimmeridgian Working Group,the International Subcommission on Jurassic Stratigraphy and the International Commission on Stratigraphy,the Global Stratotype Section and Point(GSSP)for the base of the Kimmeridgian Stage(Jurassic System)was ratified by the executive of the International Union of Geological Sciences.The boundary is placed in the upper part of Bed 35 of the Staffin Shale Formation,1.25±0.01 m below the base of Bed 36 in block F6 in the foreshore at Flodigarry,Staffin Bay,Isle of Skye,Scotland.The coordinates for the middle part of the two adjacent sections(sections F6N and F6S)are 57°39'39.5″N,6°14'43.9″W and 57°39'40.5″N,6°14'45″W;UK National Grid Scheme NG 46877139 and NG 46877142±5 m.This stratigraphic point coincides with the appearance over a short stratigraphic interval of several new ammonite taxa that delineate the base of the Subboreal ammonite Baylei Zone,the base of the Densicostata Subzone marked by the base of the flodigarriensis horizon,and,independently,the base of the Boreal ammonite Bauhini Zone.The main advantages of this locality are:the presence of a dual ammonite zonation marked by two extensively studied,well-preserved and very abundant groups of ammonites,and their preservation within a continuous section of~120 m of open marine,fossiliferous,thermally immature mudrocks with no evidence of condensation or stratigraphic gaps.Dinoflagellate cysts,magnetostratigraphy and stable isotope data from the same section provide secondary markers.The stratigraphic point is located 0.17–0.65 m below the boundary interval between the dinoflagellate cyst zones DSJ 26 and DSJ 27(equivalent to the boundary between subzones c and d of the Scriniodinium crystallinum(=Scr)Zone).
基金supported by the CGL2004-0694/BTE(MEC-CSIC)Project and grants from the 2006 and 2007 Geoconservation Projects,respectively coordinated at the Madrid and Torino universities.
文摘Following votes by the Hauterivian Working Group,the Cretaceous Subcommission and the International Commission on Stratigraphy,in December 2019 the Executive Committee of the International Union of Geological Sciences unanimously approved the proposal that the Global Stratotype Section and Point(GSSP)for the base of the Hauterivian Stage of the Lower Cretaceous be placed at the base of bed no 189 of the La Charce section,Drôme,southeast France(Vocontian Basin).This level is marked by the first appearance of the ammonite genus Acanthodiscus,which defines the base of the Acanthodiscus radiatus ammonite Zone.Complementary data include 13 ammonite and nannofossil events,and magnetostratigraphic and carbon isotope events.
基金supported by an international collaborative project of NSFC(Grant no.41420104003)the Strategic Priority Research Programs of the Chinese Academy of Sciences(Grant no.XDB26000000)the NSERC Discovery Grant to CMH.
文摘The Global Stratotype Section and Point(GSSP)for the base of the Capitanian Stage was proposed in 1999 and defined by the first appearance datum(FAD)of the conodont Jinogondolella postserrata within the lineage J.aserrata→J.postserrata→J.shannoni at Nipple Hill in West Texas,USA.Despite its widespread recognition for more than two decades,the official GSSP paper was not published,nor have its index conodont fossils been properly documented.At Nipple Hill,only the uppermost 0.5 m of the Pinery Member belongs to the Capitanian Stage.J.postserrata first appears at 19.8 m above the base of the auxiliary Frijole section.Based on U-Pb CA-ID-TIMS geochronology of ash beds from the GSSP area,the base of the Capitanian Stage has been constrained at 264.28±0.16Ma.Magnetostratigraphy suggests that the Illawarra Reversal is located slightly below the base of the Capitanian Stage.Strontium isotope chemostratigraphy generally shows a continuous decline in the 87Sr/86Sr ratio throughout the Capitanian in the GSSP area,but all ratios are higher than the Capitanian minimum of~0.7068.δ^(13)Ccarb profile shows no distinct excursion around the Wordian/Capitanian boundary interval.Detailed correlation suggests that the middle-upper part of the fusuline-based Midian Stage correlates with the Capitanian Stage.
文摘Following votes by the Barremian Working Group,the International Subcommission on Cretaceous Stratigraphy and the International Commission on Stratigraphy,the Executive Committee of the International Union of Geological Sciences unanimously approved in March 2023 the Global Stratotype Section and Point(GSSP)for the Barremian Stage(Lower Cretaceous).The base of the Barremian Stage is defined at the base of bed 171 of the Río Argos section,near Caravaca(SE Spain)and correlated by the first appearance of the ammonite species Taveraidiscus hugii.This event falls within the NC5C calcareous nannofossil Subzone,the Lilliputianella semielongata planktonic foraminiferal Zone,and the Dorothia ouachensis benthic foraminiferal Zone.It roughly coincides with the beginning of a slightly negative trend interval in theδ^(13)C curve.Indirect calibration to the magnetostratigraphic scale suggests that the boundary falls in the lowermost part of polarity chron M3r.According to the astrochronological analysis,a time interval of 0.74 myr separates the beginning of the late Hauterivian Faraoni Episode from the base of the Barremian,which is dated at 125.77 MA.
文摘The Calabrian Stage is now formally defined by the Global Boundary Stratotype Section and Point(GSSP)at Vrica,Calabria,Italy.This GSSP had previously defined the base of the Pleistocene Series.The Calabrian becomes the second stage of the Pleistocene Series and Quaternary System,following the Gelasian.The GSSP occurs at the base of the marine claystone conformably overlying sapropelic bed‘e’within Segment B in the Vrica section.This lithological level represents the primary marker for the recognition of the boundary,and is assigned an astronomical age of 1.80 Ma on the basis of sapropel calibration.It coincides with the transition from Marine Isotope Stage 65 to 64,and the underlying sapropel bed‘e’is assigned to the Mediterranean Precession-Related Sapropel layer 176.Secondary markers include calcareous plankton bioevents of widely distributed taxa.The boundary falls between the highest occurrence of Discoaster brouweri(below)and the lowest common occurrence of left-coiling Neogloboquadrina pachyderma(above),and below the lowest occurrences of medium-sized Gephyrocapsa(including G.oceanica)and Globigerinoides tenellus.The top of the Olduvai Subchron is identified c.8 m above the GSSP.Ratification of the Calabrian Stage effectively completes the Lower Pleistocene Subseries.
基金This work was jointly supported by the National Natural Science Foundation of China (Grant No. 40172014)the "SSER" of the Ministry of Science and Technology of China, and the Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology
文摘The steps and methods for the establishment of the global boundary stratotype section and point (GSSP) are summed up briefly as follows. (i) Select rock sequences of approximately the same age duration in a region, make a thorough study of their properties or attributes in order to establish the high-resolution stratigraphic units reflecting the natural rhythms in Earth's history, and proceed by multidisciplinary comprehensive studies to reveal the relationship, including time-space relation and possible mutual causality, among the various stratigraphic units and the different natural rhythms established. (ii) Seek for the 'natural break' that represents the 'major natural changes in the historical development of the Earth' in shallow marine facies areas, which is frequently the third-order sequence boundaries. (iii) Trace from shallow marine facies areas toward the continental slope and bathyal areas to seek for a continuous depositional sequence that corresponds in time span to the 'natural break' of shallow marine facies areas. (iv) Seek for a horizon within the continuous depositional sequence that approximately coincides with the maximum regressive point in the 'natural break'. This horizon is commonly within a lowerstand systems tract (LST) or a shelf margin systems tract (SMST) of the relevant third-order sequence. (v) Seek immediately above this horizon of maximum marine regression for an organic radiation or explosion event closely related to the natural boundary, which is generally the first flooding surface (FFS) of the relevant third-order sequence. (vi) Select within the organic event deposits closely related to the FFS the base boundary of a fossil taxon with widest geographical range as the Leading Group biozone for designation of the stratigraphic boundary. (vii) Select from among the sections with continuous depositional sequence formed under similar sedimentary palaeogeographic background (in general continental slope or bathyal environments) the section which possesses the shortest distance between the base boundary of the Leading Group biozone and the immediately underlying FFS of the relevant third-order sequence as the global stratotype section. The first appearance datum (FAD) of the Leading Group biozone species in the section may be regarded as the ideal GSSP. The steps suggested above are a supplement and improvement of the currently used procedures and methods for establishing GSSP. The GSSP established by using the steps and methods suggested here would make the stratigraphic boundaries better reflect the 'major natural changes in the historical development of the Earth', more readily distinguishable and easily operable in recognition and correlation, and at the same time also make the designation of boundaries more objective.
