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Mike Walker - One of the best experts on this subject based on the ideXlab platform.

  • formal ratification of the quaternary system period and the pleistocene series epoch with a base at 2 58 ma
    Journal of Quaternary Science, 2010
    Co-Authors: Philip L. Gibbard, Martin J. Head, Mike Walker
    Abstract:

    In June 2009, the Executive Committee of the International Union of Geological Sciences (IUGS) formally ratified a proposal by the International Commission on Stratigraphy to lower the base of the Quaternary System/Period to the Global Stratotype Section and Point (GSSP) of the Gelasian Stage/Age at Monte San Nicola, Sicily, Italy. The Gelasian until then had been the uppermost stage of the Pliocene Series/Epoch. The base of the Gelasian corresponds to Marine Isotope Stage 103, and has an astronomically tuned age of 2.58 Ma. A proposal that the base of the Pleistocene Series/Epoch be lowered to coincide with that of the Quaternary (the Gelasian GSSP) was also accepted by the IUGS Executive Committee. The GSSP at Vrica, Calabria, Italy, which had hitherto defined the basal boundary of both the Quaternary and the Pleistocene, remains available as the base of the Calabrian Stage/Age (now the second stage of the revised Pleistocene). In ratifying these proposals, the IUGS has acknowledged the distinctive qualities of the Quaternary by reaffirming it as a full system/period, correctly complied with the hierarchical requirements of the geological timescale by lowering the base of the Pleistocene to that of the Quaternary, and fully respected the historical and widespread current usage of both the terms 'Quaternary' and 'Pleistocene'. Copyright # 2009 John Wiley & Sons, Ltd.

  • formal ratification of the quaternary system period and the pleistocene series epoch with a base at 2 58 ma
    Journal of Quaternary Science, 2010
    Co-Authors: Philip L. Gibbard, Martin J. Head, Mike Walker
    Abstract:

    In June 2009, the Executive Committee of the International Union of Geological Sciences (IUGS) formally ratified a proposal by the International Commission on Stratigraphy to lower the base of the Quaternary System/Period to the Global Stratotype Section and Point (GSSP) of the Gelasian Stage/Age at Monte San Nicola, Sicily, Italy. The Gelasian until then had been the uppermost stage of the Pliocene Series/Epoch. The base of the Gelasian corresponds to Marine Isotope Stage 103, and has an astronomically tuned age of 2.58 Ma. A proposal that the base of the Pleistocene Series/Epoch be lowered to coincide with that of the Quaternary (the Gelasian GSSP) was also accepted by the IUGS Executive Committee. The GSSP at Vrica, Calabria, Italy, which had hitherto defined the basal boundary of both the Quaternary and the Pleistocene, remains available as the base of the Calabrian Stage/Age (now the second stage of the revised Pleistocene). In ratifying these proposals, the IUGS has acknowledged the distinctive qualities of the Quaternary by reaffirming it as a full system/period, correctly complied with the hierarchical requirements of the geological timescale by lowering the base of the Pleistocene to that of the Quaternary, and fully respected the historical and widespread current usage of both the terms 'Quaternary' and 'Pleistocene'. Copyright # 2009 John Wiley & Sons, Ltd.

Philip L. Gibbard - One of the best experts on this subject based on the ideXlab platform.

  • formal subdivision of the quaternary system period past present and future
    Quaternary International, 2015
    Co-Authors: Martin J. Head, Philip L. Gibbard
    Abstract:

    Abstract The Quaternary System/Period represents the past 2.58 million years and is officially subdivided into the Pleistocene and Holocene series/epochs, with the base of the Holocene assigned an age of 11,700 calendar years before AD 2000. The two lowest stages of the Pleistocene, the Gelasian (base 2.58 Ma) and the Calabrian (base 1.80 Ma), have been ratified and these effectively constitute the Lower Pleistocene Subseries. All other official subdivisions are pending. For the Middle Pleistocene Subseries, three candidate global boundary stratotype sections and points (GSSPs) are under consideration: the Valle di Manche in Calabria and Montalbano Jonico in Basilicata, both in southern Italy, and the Chiba section in Japan. The Matuyama–Brunhes Chron boundary (∼773 ka) serves as the principal guide for the base of the Middle Pleistocene. The base of the Upper Pleistocene Subseries is generally agreed to coincide approximately with that of the last interglacial (Marine Isotope Substage 5e ∼130 ka): the Fronte section near Taranto in southern Italy represents a possible candidate GSSP, but an Antarctic ice core might also serve this purpose. A tripartite subdivision of the Holocene, with subseries/stage boundaries at 8200 and 4200 years B.P., is also under consideration. Additional fine-scale formal subdivision of the Quaternary is being explored, with the Last Glacial Maximum serving as a test case. The “Anthropocene” is both an informal and undefined interval of time that includes the present day. Its duration, formal/informal status, rank, and method of definition are all under debate, with one suggestion that it be defined as a formal unit beginning with the world's first nuclear bomb explosion, on July 16th 1945. Suggested and proposed GSSPs are compared and critiqued. The history leading to ratification of the Quaternary Period in 2009 is examined drawing upon published and unpublished material.

  • Formal ratification of the GSSP for the base of the Calabrian Stage (second stage of the Pleistocene Series, Quaternary System)
    Episodes Journal of International Geoscience, 2012
    Co-Authors: Maria Bianca Cita, Philip L. Gibbard, Martin J. Head, B. Alloway, A.g. Beu, M. Coltorti, V.m. Hall, L. Jiagi, K.l. Knudsen, T. Van Kolfschoten
    Abstract:

    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.

  • formal ratification of the quaternary system period and the pleistocene series epoch with a base at 2 58 ma
    Journal of Quaternary Science, 2010
    Co-Authors: Philip L. Gibbard, Martin J. Head, Mike Walker
    Abstract:

    In June 2009, the Executive Committee of the International Union of Geological Sciences (IUGS) formally ratified a proposal by the International Commission on Stratigraphy to lower the base of the Quaternary System/Period to the Global Stratotype Section and Point (GSSP) of the Gelasian Stage/Age at Monte San Nicola, Sicily, Italy. The Gelasian until then had been the uppermost stage of the Pliocene Series/Epoch. The base of the Gelasian corresponds to Marine Isotope Stage 103, and has an astronomically tuned age of 2.58 Ma. A proposal that the base of the Pleistocene Series/Epoch be lowered to coincide with that of the Quaternary (the Gelasian GSSP) was also accepted by the IUGS Executive Committee. The GSSP at Vrica, Calabria, Italy, which had hitherto defined the basal boundary of both the Quaternary and the Pleistocene, remains available as the base of the Calabrian Stage/Age (now the second stage of the revised Pleistocene). In ratifying these proposals, the IUGS has acknowledged the distinctive qualities of the Quaternary by reaffirming it as a full system/period, correctly complied with the hierarchical requirements of the geological timescale by lowering the base of the Pleistocene to that of the Quaternary, and fully respected the historical and widespread current usage of both the terms 'Quaternary' and 'Pleistocene'. Copyright # 2009 John Wiley & Sons, Ltd.

  • formal ratification of the quaternary system period and the pleistocene series epoch with a base at 2 58 ma
    Journal of Quaternary Science, 2010
    Co-Authors: Philip L. Gibbard, Martin J. Head, Mike Walker
    Abstract:

    In June 2009, the Executive Committee of the International Union of Geological Sciences (IUGS) formally ratified a proposal by the International Commission on Stratigraphy to lower the base of the Quaternary System/Period to the Global Stratotype Section and Point (GSSP) of the Gelasian Stage/Age at Monte San Nicola, Sicily, Italy. The Gelasian until then had been the uppermost stage of the Pliocene Series/Epoch. The base of the Gelasian corresponds to Marine Isotope Stage 103, and has an astronomically tuned age of 2.58 Ma. A proposal that the base of the Pleistocene Series/Epoch be lowered to coincide with that of the Quaternary (the Gelasian GSSP) was also accepted by the IUGS Executive Committee. The GSSP at Vrica, Calabria, Italy, which had hitherto defined the basal boundary of both the Quaternary and the Pleistocene, remains available as the base of the Calabrian Stage/Age (now the second stage of the revised Pleistocene). In ratifying these proposals, the IUGS has acknowledged the distinctive qualities of the Quaternary by reaffirming it as a full system/period, correctly complied with the hierarchical requirements of the geological timescale by lowering the base of the Pleistocene to that of the Quaternary, and fully respected the historical and widespread current usage of both the terms 'Quaternary' and 'Pleistocene'. Copyright # 2009 John Wiley & Sons, Ltd.

Martin J. Head - One of the best experts on this subject based on the ideXlab platform.

  • formal subdivision of the quaternary system period past present and future
    Quaternary International, 2015
    Co-Authors: Martin J. Head, Philip L. Gibbard
    Abstract:

    Abstract The Quaternary System/Period represents the past 2.58 million years and is officially subdivided into the Pleistocene and Holocene series/epochs, with the base of the Holocene assigned an age of 11,700 calendar years before AD 2000. The two lowest stages of the Pleistocene, the Gelasian (base 2.58 Ma) and the Calabrian (base 1.80 Ma), have been ratified and these effectively constitute the Lower Pleistocene Subseries. All other official subdivisions are pending. For the Middle Pleistocene Subseries, three candidate global boundary stratotype sections and points (GSSPs) are under consideration: the Valle di Manche in Calabria and Montalbano Jonico in Basilicata, both in southern Italy, and the Chiba section in Japan. The Matuyama–Brunhes Chron boundary (∼773 ka) serves as the principal guide for the base of the Middle Pleistocene. The base of the Upper Pleistocene Subseries is generally agreed to coincide approximately with that of the last interglacial (Marine Isotope Substage 5e ∼130 ka): the Fronte section near Taranto in southern Italy represents a possible candidate GSSP, but an Antarctic ice core might also serve this purpose. A tripartite subdivision of the Holocene, with subseries/stage boundaries at 8200 and 4200 years B.P., is also under consideration. Additional fine-scale formal subdivision of the Quaternary is being explored, with the Last Glacial Maximum serving as a test case. The “Anthropocene” is both an informal and undefined interval of time that includes the present day. Its duration, formal/informal status, rank, and method of definition are all under debate, with one suggestion that it be defined as a formal unit beginning with the world's first nuclear bomb explosion, on July 16th 1945. Suggested and proposed GSSPs are compared and critiqued. The history leading to ratification of the Quaternary Period in 2009 is examined drawing upon published and unpublished material.

  • Formal ratification of the GSSP for the base of the Calabrian Stage (second stage of the Pleistocene Series, Quaternary System)
    Episodes Journal of International Geoscience, 2012
    Co-Authors: Maria Bianca Cita, Philip L. Gibbard, Martin J. Head, B. Alloway, A.g. Beu, M. Coltorti, V.m. Hall, L. Jiagi, K.l. Knudsen, T. Van Kolfschoten
    Abstract:

    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.

  • formal ratification of the quaternary system period and the pleistocene series epoch with a base at 2 58 ma
    Journal of Quaternary Science, 2010
    Co-Authors: Philip L. Gibbard, Martin J. Head, Mike Walker
    Abstract:

    In June 2009, the Executive Committee of the International Union of Geological Sciences (IUGS) formally ratified a proposal by the International Commission on Stratigraphy to lower the base of the Quaternary System/Period to the Global Stratotype Section and Point (GSSP) of the Gelasian Stage/Age at Monte San Nicola, Sicily, Italy. The Gelasian until then had been the uppermost stage of the Pliocene Series/Epoch. The base of the Gelasian corresponds to Marine Isotope Stage 103, and has an astronomically tuned age of 2.58 Ma. A proposal that the base of the Pleistocene Series/Epoch be lowered to coincide with that of the Quaternary (the Gelasian GSSP) was also accepted by the IUGS Executive Committee. The GSSP at Vrica, Calabria, Italy, which had hitherto defined the basal boundary of both the Quaternary and the Pleistocene, remains available as the base of the Calabrian Stage/Age (now the second stage of the revised Pleistocene). In ratifying these proposals, the IUGS has acknowledged the distinctive qualities of the Quaternary by reaffirming it as a full system/period, correctly complied with the hierarchical requirements of the geological timescale by lowering the base of the Pleistocene to that of the Quaternary, and fully respected the historical and widespread current usage of both the terms 'Quaternary' and 'Pleistocene'. Copyright # 2009 John Wiley & Sons, Ltd.

  • formal ratification of the quaternary system period and the pleistocene series epoch with a base at 2 58 ma
    Journal of Quaternary Science, 2010
    Co-Authors: Philip L. Gibbard, Martin J. Head, Mike Walker
    Abstract:

    In June 2009, the Executive Committee of the International Union of Geological Sciences (IUGS) formally ratified a proposal by the International Commission on Stratigraphy to lower the base of the Quaternary System/Period to the Global Stratotype Section and Point (GSSP) of the Gelasian Stage/Age at Monte San Nicola, Sicily, Italy. The Gelasian until then had been the uppermost stage of the Pliocene Series/Epoch. The base of the Gelasian corresponds to Marine Isotope Stage 103, and has an astronomically tuned age of 2.58 Ma. A proposal that the base of the Pleistocene Series/Epoch be lowered to coincide with that of the Quaternary (the Gelasian GSSP) was also accepted by the IUGS Executive Committee. The GSSP at Vrica, Calabria, Italy, which had hitherto defined the basal boundary of both the Quaternary and the Pleistocene, remains available as the base of the Calabrian Stage/Age (now the second stage of the revised Pleistocene). In ratifying these proposals, the IUGS has acknowledged the distinctive qualities of the Quaternary by reaffirming it as a full system/period, correctly complied with the hierarchical requirements of the geological timescale by lowering the base of the Pleistocene to that of the Quaternary, and fully respected the historical and widespread current usage of both the terms 'Quaternary' and 'Pleistocene'. Copyright # 2009 John Wiley & Sons, Ltd.

Cesare Roda - One of the best experts on this subject based on the ideXlab platform.

  • the plio pleistocene evolution of the crotone basin southern italy interplay between sedimentation tectonics and eustasy in the frame of Calabrian arc migration
    Earth-Science Reviews, 2012
    Co-Authors: Massimo Zecchin, Francesco Muto, Mauro Caffau, Dario Civile, Salvatore Critelli, Agata Di Stefano, Rosanna Maniscalco, G Sturiale, Cesare Roda
    Abstract:

    Abstract The Crotone Basin is the exposed part of a larger Neogene forearc basin developed in the Ionian Sea in the frame of the SE-ward migration of the Calabrian Arc, which led to the subduction of the Ionian lithosphere and the spreading of the Tyrrhenian back-arc Basin (central Mediterranean). Taking into account the geologic context that accompanied its accumulation, the Plio-Pleistocene part of the Crotone Basin succession is exceptionally well preserved, and consists of a suite of continental, paralic, shallow-marine and deep-marine deposits organized to form unconformity bounded stratal units that in turn compose two main tectono-stratigraphic cycles. The unconformities separating these units are well recognizable along the basin margin and tend to vanish basinwards, and they record phases of basin reorganization linked to large-scale tectonics. In particular, the basin evolution was characterized by a cyclic pattern consisting of an alternation between longer subsidence phases, that favored the accumulation of stratal units, and uplift phases that led to base-level falls and the generation of unconformities. These phases were strictly related to an alternation between active subduction of the Ionian lithosphere below the Calabrian Arc, accompanied by the spreading of the Tyrrhenian back-arc Basin and by extension and subsidence in the forearc basin, and regional-scale compressional and transpressional events, during which the Arc migration temporarily stopped. The younger uplift of the basin, started during middle Pleistocene and still active, was characterized by extensional tectonics, and its interplay with glacio-eustasy controlled the formation of marine terraces. Since the Plio-Pleistocene tectonic episodes affecting the Calabrian Arc during its SE-ward migration seem to be all recorded in the Crotone Basin, the recognition of their effects on the basin fill and their time constraint become both critical, representing a reference to develop a clearer picture on the complex evolution of the central Mediterranean.

  • raised pleistocene marine terraces of the crotone peninsula calabria southern italy facies analysis and organization of their deposits
    Sedimentary Geology, 2004
    Co-Authors: Massimo Zecchin, Ronald Nalin, Cesare Roda
    Abstract:

    Abstract Wide marine terraces well known in the Italian literature are present in the Crotone peninsula, Ionian Calabria. They are related to the interplay between Pleistocene sea-level changes and the progressive uplift of the Calabrian Arc from the middle Pleistocene onwards. We present a description of facies organization and stratigraphical characteristics of the terrace deposits, along with a new geological map of the area. All the marine terraces unconformably overlie a Plio-Pleistocene slope succession known as Cutro Clay. The oldest and highest terrace, named Cutro terrace, is placed between 90 and 200 m of elevation and is gently inclined south-eastwards. Four younger terraces placed at progressively lower elevations and dipping seawards at low angles have been recognized. The sedimentary deposits of the terraces are represented by mixed carbonate and siliciclastic bodies, up to 10 m thick. Algal reefs and grainstone to rudstone deposits are common in the south-eastern part of the study area, whereas mostly siliciclastic sandstone units of shoreface environments are more abundant northwards and westwards. The deposits of some terraces are made up of minor cycles, bounded by subaerial, transgressive, and flooding surfaces referred to minor sea-level fluctuations. NNE-, ENE-, E-, and WNW-trending normal fault systems are present within the study area and dissect the marine terraces. Specifically, the activation of ENE-trending faults took place after the formation of the oldest terrace but prior to the formation of the younger terraces.

Caterina Mesiano - One of the best experts on this subject based on the ideXlab platform.

  • FIRST RECORD OF DUGONGIDAE (MAMMALIA: SIRENIA) FROM THE FLORESTA CALCARENITES FORMATION (LATE BURDIGALIAN – EARLY LANGHIAN, REGGIO CALABRIA, SOUTHERN ITALY)
    Rivista Italiana Di Paleontologia E Stratigrafia, 2016
    Co-Authors: Giuseppe Carone, Antonella Cinzia Marra, Caterina Mesiano
    Abstract:

    A sirenian rib has been recovered at Motta San Giovanni (Reggio Calabria) in the “Floresta Calcarenites”, a Formation cropping out in Sicily and Calabria and dated late Burdigalian-Langhian. Although the rib is not a diagnostic bone for taxonomy, its presence in southern Calabria extends the knowledge about the paleobiogeography of the Family Dugongidae in the Mediterranean basin. The find is hitherto the only record of sirenians in the Floresta calcarenites. Moreover, the specimen extends back to the Early-Middle Miocene (late Burdigalian-Langhian) the occurrence of sirenians in Calabria, previously determined thanks to substantial material from the Late Miocene (Tortonian) of the Monte Poro area (Vibo Valentia).  The paleoenvironment of the Floresta calcarenites was a warm and shallow sea, consistent with the paleoecology of Dugongidae.

  • first record of dugongidae mammalia sirenia from the floresta calcarenites formation late burdigalian early langhian reggio calabria southern italy
    Rivista Italiana Di Paleontologia E Stratigrafia, 2016
    Co-Authors: Giuseppe Carone, Antonella Cinzia Marra, Caterina Mesiano
    Abstract:

    A sirenian rib has been recovered at Motta San Giovanni (Reggio Calabria) in the “Floresta Calcarenites”, a Formation cropping out in Sicily and Calabria and dated late Burdigalian-Langhian. Although the rib is not a diagnostic bone for taxonomy, its presence in southern Calabria extends the knowledge about the paleobiogeography of the Family Dugongidae in the Mediterranean basin. The find is hitherto the only record of sirenians in the Floresta calcarenites. Moreover, the specimen extends back to the Early-Middle Miocene (late Burdigalian-Langhian) the occurrence of sirenians in Calabria, previously determined thanks to substantial material from the Late Miocene (Tortonian) of the Monte Poro area (Vibo Valentia).  The paleoenvironment of the Floresta calcarenites was a warm and shallow sea, consistent with the paleoecology of Dugongidae.