The Experts below are selected from a list of 750 Experts worldwide ranked by ideXlab platform
Etienne Steurbaut - One of the best experts on this subject based on the ideXlab platform.
-
depositional changes during the danian Selandian transition in loubieng france zumaia spain and sidi nasseur tunisia insights from and limits of rock magnetism
Geological Magazine, 2019Co-Authors: Sébastien Wouters, Johan Yans, Simo Spassov, Mathieu Martinez, Etienne Steurbaut, Jean-yves Storme, Xavier DevleeschouwerAbstract:Depositional changes are studied in three sections encompassing the Danian–Selandian transition, Loubieng (France), Zumaia (Spain) and Sidi Nasseur (Tunisia), using magnetic susceptibility as a proxy. Additional rock-magnetic analyses are used to avoid ambiguous interpretation of magnetic susceptibility. The magnetic susceptibility, measured on 90 to 270 samples per section, is mainly controlled by paramagnetic minerals and linked to detrital input. Major increases in the detrital input are correlated to the end of the Latest Danian Event, a hyperthermal, and to the Danian–Selandian boundary. In Loubieng, two gradual increases in magnetic susceptibility within limestones beds precede the major detrital input increases, and start synchronously with the beginning of the Latest Danian Event and the onset of haematite deposition around the Danian–Selandian boundary, respectively. This haematite is suspected to be of primary origin based, among other things, on low magnetic viscosity values, which is used here as an indicator of diagenetic origin in haematite and goethite. The red levels where haematite is interpreted to be of primary origin could be linked to the hyperthermal event previously hypothesized for the basal Selandian. The comparison of the magnetic susceptibility, chemo- and biostratigraphic data between the three sections highlights the condensed nature of the sedimentation around the Danian–Selandian boundary in the sections of the Atlantic realm. The lower part of the Selandian shows a particularly low sedimentation rate at Zumaia compared to Loubieng and Sidi Nasseur. The latter displays the most complete record of the three.
-
Depositional changes during the Danian–Selandian transition in Loubieng (France), Zumaia (Spain) and Sidi Nasseur (Tunisia): insights from and limits of rock magnetism
Geological Magazine, 2019Co-Authors: Sébastien Wouters, Johan Yans, Simo Spassov, Mathieu Martinez, Etienne Steurbaut, Jean-yves Storme, Xavier DevleeschouwerAbstract:Depositional changes are studied in three sections encompassing the Danian–Selandian transition, Loubieng (France), Zumaia (Spain) and Sidi Nasseur (Tunisia), using magnetic susceptibility as a proxy. Additional rock-magnetic analyses are used to avoid ambiguous interpretation of magnetic susceptibility. The magnetic susceptibility, measured on 90 to 270 samples per section, is mainly controlled by paramagnetic minerals and linked to detrital input. Major increases in the detrital input are correlated to the end of the Latest Danian Event, a hyperthermal, and to the Danian–Selandian boundary. In Loubieng, two gradual increases in magnetic susceptibility within limestones beds precede the major detrital input increases, and start synchronously with the beginning of the Latest Danian Event and the onset of haematite deposition around the Danian–Selandian boundary, respectively. This haematite is suspected to be of primary origin based, among other things, on low magnetic viscosity values, which is used here as an indicator of diagenetic origin in haematite and goethite. The red levels where haematite is interpreted to be of primary origin could be linked to the hyperthermal event previously hypothesized for the basal Selandian. The comparison of the magnetic susceptibility, chemo- and biostratigraphic data between the three sections highlights the condensed nature of the sedimentation around the Danian–Selandian boundary in the sections of the Atlantic realm. The lower part of the Selandian shows a particularly low sedimentation rate at Zumaia compared to Loubieng and Sidi Nasseur. The latter displays the most complete record of the three.
-
New Paleocene Sepiid Coleoids (Cephalopoda) from Egypt: Evolutionary Significance and Origin of the Sepiid ‘Rostrum’
2016Co-Authors: Martin Košťák, Robert P Speijer, John W. M. Jagt, Peter Stassen, Etienne SteurbautAbstract:New coleoid cephalopods, assignable to the order Sepiida, are recorded from the Selandian/Thanetian boundary interval (Middle to Upper Paleocene transition, c. 59.2 Ma) along the southeastern margin (Toshka Lakes) of the Western Desert in Egypt. The two genera recognised, Aegyptosaepia n. gen. and?Anomalosaepia Weaver and Ciampaglio, are placed in the families Belosaepiidae and?Anomalosaepiidae, respectively. They constitute the oldest record to date of sepiids with a ‘rostrum-like ’ prong. In addition, a third, generically and specifically indeterminate coleoid is represented by a single rostrum-like find. The taxonomic assignment of the material is based on apical parts (as preserved), i.e., guard, apical prong (or ‘rostrum-like ’ structure), phragmocone and (remains of) protoconch, plus shell mineralogy. We here confirm the shell of early sepiids to have been bimineralic, i.e., composed of both calcite and aragonite. Aegyptosaepia lugeri n. gen., n. sp. reveals some similarities to later species of Belosaepia, in particular the possession of a distinct prong. General features of the phragmocone and protoconch of the new form are similar to both Belocurta (Middle Danian [Lower Paleocene]) and Belosaepia (Eocene). However, breviconic coiling and the presence of a longer ventral conotheca indicate closer ties with late Maastrichtian–Middle Danian Ceratisepia. In this respect, Aegyptosaepia n. gen. constitutes a link between Ceratisepia and the Eocene Belosaepia. The occurrence of the new genus near the Selandian/Thanetian boundary suggests an earlier origin o
-
integrated bio chemostratigraphical correlations and climatic evolution across the danian Selandian boundary at low latitudes
Palaeogeography Palaeoclimatology Palaeoecology, 2014Co-Authors: Etienne Steurbaut, Jean-yves Storme, Xavier Devleeschouwer, Christian Dupuis, Paola Iacumin, Gaëtan Rochez, Johan YansAbstract:Abstract The Global Boundary Stratotype Section and Point for the base of the Selandian Stage is defined in the Zumaia section (Spain) at an abrupt change in lithology (base of Itzurun Formation), which coincides with the onset of a negative carbonate carbon isotope shift. However, this lithological change is not always very well expressed in other sections. In order to document the stratigraphic position of the Danian/Selandian boundary (DSB) on a more global scale, we have investigated three sections across the DSB, the Zumaia reference section (GSSP), the Loubieng section (auxiliary DSB reference section, France) and the Sidi Nasseur section (Tunisia). The Danian/Selandian boundary interval is subdivided and correlated throughout low latitudes, from the Altlantic Bay of Biscay to the Southern Tethys, on the basis of seven calcareous nannofossil and planktonic foraminiferal events (E-events). The base of the Selandian is proved to coincide with the end of the Braarudosphaera acme, which correlates with the lowest consistent occurrence (LCsO) of Lithoptychius aff. bitectus (= Fasciculithus janii sensu Steurbaut and Sztrakos, 2008) (event E4), but which is slightly posterior to the second radiation of the fasciculiths, up to now considered to represent the primary correlation tool of the DSB. A short-term δ 13 C org negative excursion, associated with an increase in p CO 2 is recorded at the very base of the Selandian. It is interpreted as a short period of global warming (hyperthermal), the duration of which is estimated at ~ 30 kyr. It is followed in all the three studied sections by a long-term decoupled carbon isotope event, marked by increasing δ 13 C org and decreasing δ 13 C carb values. It may reflect a period of climatic cooling of a few 100 kyr, interpreted as a possible precursor of the global cooling event, marking the late Paleocene in the North Atlantic realm. The integration of the biostratigraphic and the isotope data indicates major differences in sedimentation rates during the early Selandian in the studied sections, but there is no evidence of substantial breaks in sedimentation in any of the sections during this interval. The lithological shift at the base of the Selandian points to an abrupt palaeoenvironmental reorganisation, although our integrated bio-chemostratigraphical investigation does not allow for estimating its duration nor the presence of a hiatus at that time.
-
Integrated bio-chemostratigraphical correlations and climatic evolution across the Danian–Selandian boundary at low latitudes
Palaeogeography Palaeoclimatology Palaeoecology, 2014Co-Authors: Jean-yves Storme, Etienne Steurbaut, Xavier Devleeschouwer, Christian Dupuis, Paola Iacumin, Gaëtan Rochez, Johan YansAbstract:Abstract The Global Boundary Stratotype Section and Point for the base of the Selandian Stage is defined in the Zumaia section (Spain) at an abrupt change in lithology (base of Itzurun Formation), which coincides with the onset of a negative carbonate carbon isotope shift. However, this lithological change is not always very well expressed in other sections. In order to document the stratigraphic position of the Danian/Selandian boundary (DSB) on a more global scale, we have investigated three sections across the DSB, the Zumaia reference section (GSSP), the Loubieng section (auxiliary DSB reference section, France) and the Sidi Nasseur section (Tunisia). The Danian/Selandian boundary interval is subdivided and correlated throughout low latitudes, from the Altlantic Bay of Biscay to the Southern Tethys, on the basis of seven calcareous nannofossil and planktonic foraminiferal events (E-events). The base of the Selandian is proved to coincide with the end of the Braarudosphaera acme, which correlates with the lowest consistent occurrence (LCsO) of Lithoptychius aff. bitectus (= Fasciculithus janii sensu Steurbaut and Sztrakos, 2008) (event E4), but which is slightly posterior to the second radiation of the fasciculiths, up to now considered to represent the primary correlation tool of the DSB. A short-term δ 13 C org negative excursion, associated with an increase in p CO 2 is recorded at the very base of the Selandian. It is interpreted as a short period of global warming (hyperthermal), the duration of which is estimated at ~ 30 kyr. It is followed in all the three studied sections by a long-term decoupled carbon isotope event, marked by increasing δ 13 C org and decreasing δ 13 C carb values. It may reflect a period of climatic cooling of a few 100 kyr, interpreted as a possible precursor of the global cooling event, marking the late Paleocene in the North Atlantic realm. The integration of the biostratigraphic and the isotope data indicates major differences in sedimentation rates during the early Selandian in the studied sections, but there is no evidence of substantial breaks in sedimentation in any of the sections during this interval. The lithological shift at the base of the Selandian points to an abrupt palaeoenvironmental reorganisation, although our integrated bio-chemostratigraphical investigation does not allow for estimating its duration nor the presence of a hiatus at that time.
Sherif Farouk - One of the best experts on this subject based on the ideXlab platform.
-
Foraminiferal biostratigraphy and paleoenvironments of the Danian-Selandian succession at the Kharga Oasis, Western Desert, Egypt
Arabian Journal of Geosciences, 2019Co-Authors: Abdel Galil A Hewaidy, Sherif Farouk, Youssef S BazeenAbstract:The present work deals with the foraminiferal investigations and analyses of the Danian-Selandian (D-S) succession at Naqb El-Rufuf and Umm El-Ghanayim sections in the Kharga Oasis. Five planktonic foraminiferal zones and subzones (P1c, P2, P3a, P3b, and P4a) were recognized within the studied sections. The D/S stage boundary is characterized by a faunal break at the P3/P4 zonal boundary owing to completely or partially absence of the P3b subzone. This hiatus reveals the dual signature of both the eustatic sea-level changes and the regional tectonic event of the Syrian Arc System. The studied interval is subdivided into three transgressive-regressive sequences bounded by three sequence boundaries at the Cretaceous-Paleogene (K/Pg.) boundary, the boundary between P3a/P3b subzones and the D/S boundary, respectively. The D/S transition is associated with substantial changes in the structure and composition of the foraminiferal assemblages point to extensive paleoenvironmental turnover. The latest Danian sediments were deposited under deep inner-shallow middle neritic environments with oxygen-depleted bottom water conditions and increased trophic level, where an outer neritic environment with meso-oligotrophic and well-oxygenated bottom water conditions prevailed during the deposition of the Selandian deposits.
-
the Selandian thanetian transition of the naqb el rufuf section kharga oasis western desert egypt foraminiferal biostratigraphy and sequence stratigraphy implications
Journal of African Earth Sciences, 2019Co-Authors: Abdel Galil A Hewaidy, Sherif Farouk, Youssef S BazeenAbstract:Abstract The Selandian-Thanetian (S/Th) succession is extensively represented and well exposed along the eastern escarpments of the Kharga Oasis, Western Desert, encompasses the upper part of the Dakhla Formation, Tarawan Formation and the lower part of the Esna Formation. This study based on the qualitative and quantitative investigation of the planktonic and benthic foraminiferal assemblages aims to assess and specify the S/Th transition in terms of the biostratigraphic, paleoecologic and sequence stratigraphic analyses. The studied interval is subdivided into three 3rd order depositional sequences (Seq. 1, Seq. 2 and Seq. 3) separated by two sequence boundaries at the Dakhla/Tarawan (SB 1) and the Tarawan/Esna (SB 2) contacts, respectively. The S/Th boundary is placed at the Maximum Flooding Surface (MFS) of the second depositional sequence (Seq. 2) within the Tarawan Formation and lies at about 6 m above the base of a distinct thin layer related to the Mid-Paleocene Biotic Event (MPBE). The S/Th MFS is characterized by a relatively highest positive peak in the P/B ratio (90%) and the common occurrence of the bathyal benthic taxa. The reported MFS displays great correspondence with the eustatic sea-level related to the timing and extent that can be treated as a secondary criterion relevant for delineating and correlating the Selandian-Thanetian transition everywhere.
-
The Selandian/Thanetian transition of the Naqb El-Rufuf section, Kharga Oasis, Western Desert, Egypt: Foraminiferal biostratigraphy and sequence stratigraphy implications
Journal of African Earth Sciences, 2019Co-Authors: Abdel Galil A Hewaidy, Sherif Farouk, Youssef S BazeenAbstract:Abstract The Selandian-Thanetian (S/Th) succession is extensively represented and well exposed along the eastern escarpments of the Kharga Oasis, Western Desert, encompasses the upper part of the Dakhla Formation, Tarawan Formation and the lower part of the Esna Formation. This study based on the qualitative and quantitative investigation of the planktonic and benthic foraminiferal assemblages aims to assess and specify the S/Th transition in terms of the biostratigraphic, paleoecologic and sequence stratigraphic analyses. The studied interval is subdivided into three 3rd order depositional sequences (Seq. 1, Seq. 2 and Seq. 3) separated by two sequence boundaries at the Dakhla/Tarawan (SB 1) and the Tarawan/Esna (SB 2) contacts, respectively. The S/Th boundary is placed at the Maximum Flooding Surface (MFS) of the second depositional sequence (Seq. 2) within the Tarawan Formation and lies at about 6 m above the base of a distinct thin layer related to the Mid-Paleocene Biotic Event (MPBE). The S/Th MFS is characterized by a relatively highest positive peak in the P/B ratio (90%) and the common occurrence of the bathyal benthic taxa. The reported MFS displays great correspondence with the eustatic sea-level related to the timing and extent that can be treated as a secondary criterion relevant for delineating and correlating the Selandian-Thanetian transition everywhere.
-
Calcareous nannofossil biostratigraphy of the Paleocene at the Misheiti section, East Central Sinai, Egypt
Arabian Journal of Geosciences, 2017Co-Authors: Atef M. Kasem, Sherif Farouk, Mahmoud Al-faris, Sherwood W. Wise, Esam ZahranAbstract:Integration of calcareous nannofossil data, δ13C and δ18O values, and carbonate contents of the lower Paleocene–upper Paleocene sequence that crops out at the Misheiti section, East Central Sinai, Egypt, were used to denote the Danian/Selandian (D/S) and Selandian/Thanetian (S/T) stage boundaries. The study interval belongs to the Dakhla and Tarawan formations. Four calcareous nannofossil zones (NP4, NP5, NP6, and NP7/8) were recognized. The base of the Selandian Stage is tentatively placed at the lowest occurrences (LOs) of taxa ascribable to the second radiation of fasciculiths (i.e., Lithoptychius janii). This level is marked by a sudden drop of δ13C and δ18O values and carbonate content. No distinctive lithological changes were observed across the D/S boundary at the study section. A hiatus at the NP5/NP6 zonal boundary is indicated by the condensation of zones NP5 and NP6.
-
Calcareous nannofossil biostratigraphy of the Paleocene at the Misheiti section, East Central Sinai, Egypt
Arabian Journal of Geosciences, 2017Co-Authors: Atef M. Kasem, Sherif Farouk, Mahmoud Al-faris, Sherwood Wise, Esam ZahranAbstract:Integration of calcareous nannofossil data, δ^13C and δ^18O values, and carbonate contents of the lower Paleocene–upper Paleocene sequence that crops out at the Misheiti section, East Central Sinai, Egypt, were used to denote the Danian/Selandian (D/S) and Selandian/Thanetian (S/T) stage boundaries. The study interval belongs to the Dakhla and Tarawan formations. Four calcareous nannofossil zones (NP4, NP5, NP6, and NP7/8) were recognized. The base of the Selandian Stage is tentatively placed at the lowest occurrences (LOs) of taxa ascribable to the second radiation of fasciculiths (i.e., Lithoptychius janii ). This level is marked by a sudden drop of δ^13C and δ^18O values and carbonate content. No distinctive lithological changes were observed across the D/S boundary at the study section. A hiatus at the NP5/NP6 zonal boundary is indicated by the condensation of zones NP5 and NP6. The base of the Thanetian is placed at the base of Zone NP7/8 at the lithological change observed in correspondence to the boundary between the Dakhla and Tarawan formations . The δ^13C and δ^18O values abruptly decrease slightly above the base of Zone NP7/8. No consistent variations in the carbonate contents were recorded within Zone NP6 or across the NP6/NP7/8 zonal boundary.
Birger Schmitz - One of the best experts on this subject based on the ideXlab platform.
-
the global stratotype sections and points for the bases of the Selandian middle paleocene and thanetian upper paleocene stages at zumaia spain
Episodes, 2011Co-Authors: Birger Schmitz, Victoriano Pujalte, Simonetta Monechi, Robert P Speijer, Laia Alegret, Ignacio Arenillas, Xabier Orueetxebarria, Estibaliz Apellaniz, Eustoquio Molina, Mariepierre AubryAbstract:The global stratotype sections and points for the bases of the Selandian (Middle Paleocene) and Thanetian (Upper Paleocene) stages have been defined in the coastal cliff along the Itzurun Beach at the town of Zumaia in the Basque Country, northern Spain. In the hemipelagic section exposed at Zumaia the base of the Selandian Stage has been placed at the base of the Itzurun Formation, ca. 49 m above the Cretaceous/ Paleogene boundary. At the base of the Selandian, marls replace the succession of Danian red limestone and limestone-marl couplets. The best marine, global correlation criterion for the basal Selandian is the second radiation of the important calcareous nannofossil group, the fasciculiths. Species such as Fasciculithus ulii, F. billii, F. janii, F. involutus, F. pileatus and F. Tympaniformis have their first appearance in the interval from a few decimetres below up to 1.1 m above the base of the Selandian. The marker species for nannofossil Zone NP5, F. tympaniformis , first occurs 1.1 m above the base. Excellent cyclostratigraphy and magnetostratigraphy in the section creates further correlation potential, with the base of the Selandian occuring 30 precession cycles (630 kyr) above the top of magnetochron C27n. Profound changes in sedimentology related to a major sea-level fall characterize the Danian-Selandian transition in sections along the margins of the North Atlantic. The base of the Thanetian Stage is placed in the same section ca. 78 m above the Cretaceous/Paleogene boundary. It is defined at a level 2.8 m or eight precession cycles above the base of the core of the distinct clay-rich interval associated with the Mid-Paleocene Biotic Event, and it corresponds to the base of magnetochron C26n in the section. The base of the Thanetian is not associated with any significant change in marine micro-fauna or flora. The calcareous nannofossil Zone NP6, marked by the first occurrence of Heliolithus kleinpelli starts ca. 6.5 m below the base of the Thanetian. The definitions of the global stratotype points for the bases of the Selandian and Thanetian stages are in good agreements with the definitions in the historical stratotype sections in Denmark and England, respectively.
-
Foraminiferal and δ13C isotopic event-stratigraphy across the Danian–Selandian transition at Zumaya (northern Spain): chronostratigraphic implications
Terra Nova, 2008Co-Authors: Ignacio Arenillas, Eustoquio Molina, Silvia Ortiz, Birger SchmitzAbstract:unconformity, characterized by a ma- jor lithological shift from greyish white, oxic limestone ⁄ chalk of the Danskekalk Fm., upper Danian, to suboxic, glauconitic green sand of the Lellinge Greensand Fm., lower Selan- dian, overlain by grey marl and clay of the Kerteminde Marl Fm., middle Selandian. This unconformity was correlated with the sequence bound- ary between cycles TA 1.3 and TA 1.4 ABSTRACT The Zumaya section, northern Spain, is a suitable candidate to define the Global Stratotype Section and Point for the base of the Selandian Stage (Palaeocene) because of its excellent accessibility, exposure and stratigraphic continuity. Uncertain- ties exist, however, with regard to the stratigraphic horizon where to place the Danian ⁄ Selandian (D ⁄ S) boundary. Five potential stratigraphic horizons (HDS1 to HDS5) to define the D ⁄ S boundary have been identified at Zumaya, based on integrated stratigraphic studies that include quantitative plank- tic and benthic foraminiferal results, as well as d 13 C isotopic and lithological data. Two of these horizons (HDS2 and HDS4) placed in Zone C26r appear to have particularly good potential for serving as the D ⁄ S boundary marker, because they may represent significant global palaeoceanographic, palaeoclimatic and eustatic events.
-
foraminiferal and δ13c isotopic event stratigraphy across the danian Selandian transition at zumaya northern spain chronostratigraphic implications
Terra Nova, 2008Co-Authors: Ignacio Arenillas, Eustoquio Molina, Silvia Ortiz, Birger SchmitzAbstract:unconformity, characterized by a ma- jor lithological shift from greyish white, oxic limestone ⁄ chalk of the Danskekalk Fm., upper Danian, to suboxic, glauconitic green sand of the Lellinge Greensand Fm., lower Selan- dian, overlain by grey marl and clay of the Kerteminde Marl Fm., middle Selandian. This unconformity was correlated with the sequence bound- ary between cycles TA 1.3 and TA 1.4 ABSTRACT The Zumaya section, northern Spain, is a suitable candidate to define the Global Stratotype Section and Point for the base of the Selandian Stage (Palaeocene) because of its excellent accessibility, exposure and stratigraphic continuity. Uncertain- ties exist, however, with regard to the stratigraphic horizon where to place the Danian ⁄ Selandian (D ⁄ S) boundary. Five potential stratigraphic horizons (HDS1 to HDS5) to define the D ⁄ S boundary have been identified at Zumaya, based on integrated stratigraphic studies that include quantitative plank- tic and benthic foraminiferal results, as well as d 13 C isotopic and lithological data. Two of these horizons (HDS2 and HDS4) placed in Zone C26r appear to have particularly good potential for serving as the D ⁄ S boundary marker, because they may represent significant global palaeoceanographic, palaeoclimatic and eustatic events.
Victoriano Pujalte - One of the best experts on this subject based on the ideXlab platform.
-
settling the danian astronomical time scale a prospective global unit stratotype at zumaia basque basin
2014Co-Authors: Jaume Dinaresturell, Victoriano Pujalte, Thomas Westerhold, Ursula Rohl, Dick KroonAbstract:We present a new Danian correlation framework between the land-based Zumaia and Sopelana sections from the Basque Basin and marine-based sections drilled during ODP Legs 198 (Shatsky Rise, North Pacific) and 208 (Walvis Ridge, South Atlantic) that reconciles magnetostratigraphy and the short and long eccentricity cycle patterns among the records. A new whole-rock δ13C isotope record at Zumaia is compared to that of Site 1262. This allows the question of whether the Danian consists of 10 or 11 consecutive 405-kyr eccentricity cycles to be tested. The new consistent stratigraphic framework enables accurate estimates to be made of ages for magnetostratigraphic boundaries, bioevents, and sedimentation rates. Low sedimentation rates appear common in all records in the mid-Danian interval along the upper part of chron C28n, including conspicuous condensed intervals in some of the oceanic records that in the past have hampered the proper identification of cycles. Notably, we challenge the correlation to the Pacific Sites 1209–1210 that were offset by as much as one 405-kyr cycle in previous interpretations (i.e., the Fasciculithus spp. LO, which approximates the Danian–Selandian boundary, and the TC27n event were at odds between oceans in the interpretation of Hilgen et al. 2010). Finally, we envisage that the Zumaia section, which already hosts the Selandian GSSP, could serve as the global Danian stratotype.
-
the global stratotype sections and points for the bases of the Selandian middle paleocene and thanetian upper paleocene stages at zumaia spain
Episodes, 2011Co-Authors: Birger Schmitz, Victoriano Pujalte, Simonetta Monechi, Robert P Speijer, Laia Alegret, Ignacio Arenillas, Xabier Orueetxebarria, Estibaliz Apellaniz, Eustoquio Molina, Mariepierre AubryAbstract:The global stratotype sections and points for the bases of the Selandian (Middle Paleocene) and Thanetian (Upper Paleocene) stages have been defined in the coastal cliff along the Itzurun Beach at the town of Zumaia in the Basque Country, northern Spain. In the hemipelagic section exposed at Zumaia the base of the Selandian Stage has been placed at the base of the Itzurun Formation, ca. 49 m above the Cretaceous/ Paleogene boundary. At the base of the Selandian, marls replace the succession of Danian red limestone and limestone-marl couplets. The best marine, global correlation criterion for the basal Selandian is the second radiation of the important calcareous nannofossil group, the fasciculiths. Species such as Fasciculithus ulii, F. billii, F. janii, F. involutus, F. pileatus and F. Tympaniformis have their first appearance in the interval from a few decimetres below up to 1.1 m above the base of the Selandian. The marker species for nannofossil Zone NP5, F. tympaniformis , first occurs 1.1 m above the base. Excellent cyclostratigraphy and magnetostratigraphy in the section creates further correlation potential, with the base of the Selandian occuring 30 precession cycles (630 kyr) above the top of magnetochron C27n. Profound changes in sedimentology related to a major sea-level fall characterize the Danian-Selandian transition in sections along the margins of the North Atlantic. The base of the Thanetian Stage is placed in the same section ca. 78 m above the Cretaceous/Paleogene boundary. It is defined at a level 2.8 m or eight precession cycles above the base of the core of the distinct clay-rich interval associated with the Mid-Paleocene Biotic Event, and it corresponds to the base of magnetochron C26n in the section. The base of the Thanetian is not associated with any significant change in marine micro-fauna or flora. The calcareous nannofossil Zone NP6, marked by the first occurrence of Heliolithus kleinpelli starts ca. 6.5 m below the base of the Thanetian. The definitions of the global stratotype points for the bases of the Selandian and Thanetian stages are in good agreements with the definitions in the historical stratotype sections in Denmark and England, respectively.
-
closing the mid palaeocene gap toward a complete astronomically tuned palaeocene epoch and Selandian and thanetian gssps at zumaia basque basin w pyrenees
Earth and Planetary Science Letters, 2007Co-Authors: Jaume Dinaresturell, Juan Ignacio Baceta, Gilen Bernaola, Xabier Orueetxebarria, Victoriano PujalteAbstract:Abstract An integrated magneto-, bio- and cyclostratigraphic framework is presented for the Mid-Palaeocene interval from the (hemi)pelagic sea-cliff section of Zumaia in the Basque basin. The new ∼ 55 m long studied section expands about 3.5 Myr and closes the gap between previously published integrated studies in the section. The occurrence of magnetochron C26n is now documented, and its duration (complemented also by data from the Ibaeta section), and that for chrons C26r and C25r is estimated by counting precession related lithologic couplets assigned to have 21-kyr duration (C25r = ∼ 1449 kyr, C26n = ∼ 231 kyr, C26r = ∼ 2877 kyr). Consequently, the Zumaia section now provides the first complete Palaeocene astronomically derived chronology, rendering this section a master reference section. Due to limitations in the orbital calculations and uncertainties in the radiometric dating method no robust tuning and absolute ages can be given for the moment. However, the FOs (First Occurrences) of key calcareous plankton species and the Mid Palaeocene Biotic Event (MPBE) are placed within the magnetostratigraphic and cyclostratigraphic template along the studied Mid-Palaeocene interval. In addition, the dataset provides the key elements for a proper settling of the Thanetian and Selandian Global Stratotype Section and Point (GSSPs), which is one of the primary objectives of the ICS (International Commission of Stratigraphy). We consider the base of chron C26n and the criteria associated to the lithostratigraphic change between the Danian Limestone Fm and the Itzurun marl Fm at Zumaia, as the respective delimiting points for the Thanetian and Selandian bases as recently agreed by the Paleocene Working Group of the International Subcommission of the Paleogene Stratigraphy of the ICS. Consequently, the duration of the Thanetian, Selandian and Danian component stages can be estimated at Zumaia to be about ∼ 3129 kyr, ∼ 2163 kyr and ∼ 4324 kyr respectively (see text for error considerations). However, the MPBE located 8 precession cycles below the base of C26n in correspondence to a short eccentricity maxima at Zumaia, could also serve as a guiding criteria to approximate or redefine the Thanetian base if this level demonstrated synchronous.
-
Closing the Mid-Palaeocene gap: Toward a complete astronomically tuned Palaeocene Epoch and Selandian and Thanetian GSSPs at Zumaia (Basque Basin, W Pyrenees)
Earth and Planetary Science Letters, 2007Co-Authors: Jaume Dinarès-turell, Gilen Bernaola, Juan Ignacio Baceta, Xabier Orue-etxebarria, Victoriano PujalteAbstract:An integrated magneto-, bio- and cyclostratigraphic framework is presented for the Mid-Palaeocene interval from the (hemi) pelagic sea-cliff section of Zumaia in the Basque basin. The new ∼55 m long studied section expands about 3.5 Myr and closes the gap between previously published integrated studies in the section. The occurrence of magnetochron C26n is now documented, and its duration (complemented also by data from the Ibaeta section), and that for chrons C26r and C25r is estimated by counting precession related lithologic couplets assigned to have 21-kyr duration (C25r=∼1449 kyr, C26n=∼231 kyr, C26r=∼2877 kyr). Consequently, the Zumaia section now provides the first complete Palaeocene astronomically derived chronology, rendering this section a master reference section. Due to limitations in the orbital calculations and uncertainties in the radiometric dating method no robust tuning and absolute ages can be given for the moment. However, the FOs (First Occurrences) of key calcareous plankton species and the Mid Palaeocene Biotic Event (MPBE) are placed within the magnetostratigraphic and cyclostratigraphic template along the studied Mid-Palaeocene interval. In addition, the dataset provides the key elements for a proper settling of the Thanetian and Selandian Global Stratotype Section and Point (GSSPs), which is one of the primary objectives of the ICS (International Commission of Stratigraphy). We consider the base of chron C26n and the criteria associated to the lithostratigraphic change between the Danian Limestone Fm and the Itzurun marl Fm at Zumaia, as the respective delimiting points for the Thanetian and Selandian bases as recently agreed by the Paleocene Working Group of the International Subcommission of the Paleogene Stratigraphy of the ICS. Consequently, the duration of the Thanetian, Selandian and Danian component stages can be estimated at Zumaia to be about ∼3129 kyr, ∼2163 kyr and ∼4324 kyr respectively (see text for error considerations). However, the MPBE located 8 precession cycles below the base of C26n in correspondence to a short eccentricity maxima at Zumaia, could also serve as a guiding criteria to approximate or redefine the Thanetian base if this level demonstrated synchronous.Published450–4672.2. Laboratorio di paleomagnetismoJCR Journalreserve
Johan Yans - One of the best experts on this subject based on the ideXlab platform.
-
depositional changes during the danian Selandian transition in loubieng france zumaia spain and sidi nasseur tunisia insights from and limits of rock magnetism
Geological Magazine, 2019Co-Authors: Sébastien Wouters, Johan Yans, Simo Spassov, Mathieu Martinez, Etienne Steurbaut, Jean-yves Storme, Xavier DevleeschouwerAbstract:Depositional changes are studied in three sections encompassing the Danian–Selandian transition, Loubieng (France), Zumaia (Spain) and Sidi Nasseur (Tunisia), using magnetic susceptibility as a proxy. Additional rock-magnetic analyses are used to avoid ambiguous interpretation of magnetic susceptibility. The magnetic susceptibility, measured on 90 to 270 samples per section, is mainly controlled by paramagnetic minerals and linked to detrital input. Major increases in the detrital input are correlated to the end of the Latest Danian Event, a hyperthermal, and to the Danian–Selandian boundary. In Loubieng, two gradual increases in magnetic susceptibility within limestones beds precede the major detrital input increases, and start synchronously with the beginning of the Latest Danian Event and the onset of haematite deposition around the Danian–Selandian boundary, respectively. This haematite is suspected to be of primary origin based, among other things, on low magnetic viscosity values, which is used here as an indicator of diagenetic origin in haematite and goethite. The red levels where haematite is interpreted to be of primary origin could be linked to the hyperthermal event previously hypothesized for the basal Selandian. The comparison of the magnetic susceptibility, chemo- and biostratigraphic data between the three sections highlights the condensed nature of the sedimentation around the Danian–Selandian boundary in the sections of the Atlantic realm. The lower part of the Selandian shows a particularly low sedimentation rate at Zumaia compared to Loubieng and Sidi Nasseur. The latter displays the most complete record of the three.
-
Depositional changes during the Danian–Selandian transition in Loubieng (France), Zumaia (Spain) and Sidi Nasseur (Tunisia): insights from and limits of rock magnetism
Geological Magazine, 2019Co-Authors: Sébastien Wouters, Johan Yans, Simo Spassov, Mathieu Martinez, Etienne Steurbaut, Jean-yves Storme, Xavier DevleeschouwerAbstract:Depositional changes are studied in three sections encompassing the Danian–Selandian transition, Loubieng (France), Zumaia (Spain) and Sidi Nasseur (Tunisia), using magnetic susceptibility as a proxy. Additional rock-magnetic analyses are used to avoid ambiguous interpretation of magnetic susceptibility. The magnetic susceptibility, measured on 90 to 270 samples per section, is mainly controlled by paramagnetic minerals and linked to detrital input. Major increases in the detrital input are correlated to the end of the Latest Danian Event, a hyperthermal, and to the Danian–Selandian boundary. In Loubieng, two gradual increases in magnetic susceptibility within limestones beds precede the major detrital input increases, and start synchronously with the beginning of the Latest Danian Event and the onset of haematite deposition around the Danian–Selandian boundary, respectively. This haematite is suspected to be of primary origin based, among other things, on low magnetic viscosity values, which is used here as an indicator of diagenetic origin in haematite and goethite. The red levels where haematite is interpreted to be of primary origin could be linked to the hyperthermal event previously hypothesized for the basal Selandian. The comparison of the magnetic susceptibility, chemo- and biostratigraphic data between the three sections highlights the condensed nature of the sedimentation around the Danian–Selandian boundary in the sections of the Atlantic realm. The lower part of the Selandian shows a particularly low sedimentation rate at Zumaia compared to Loubieng and Sidi Nasseur. The latter displays the most complete record of the three.
-
integrated bio chemostratigraphical correlations and climatic evolution across the danian Selandian boundary at low latitudes
Palaeogeography Palaeoclimatology Palaeoecology, 2014Co-Authors: Etienne Steurbaut, Jean-yves Storme, Xavier Devleeschouwer, Christian Dupuis, Paola Iacumin, Gaëtan Rochez, Johan YansAbstract:Abstract The Global Boundary Stratotype Section and Point for the base of the Selandian Stage is defined in the Zumaia section (Spain) at an abrupt change in lithology (base of Itzurun Formation), which coincides with the onset of a negative carbonate carbon isotope shift. However, this lithological change is not always very well expressed in other sections. In order to document the stratigraphic position of the Danian/Selandian boundary (DSB) on a more global scale, we have investigated three sections across the DSB, the Zumaia reference section (GSSP), the Loubieng section (auxiliary DSB reference section, France) and the Sidi Nasseur section (Tunisia). The Danian/Selandian boundary interval is subdivided and correlated throughout low latitudes, from the Altlantic Bay of Biscay to the Southern Tethys, on the basis of seven calcareous nannofossil and planktonic foraminiferal events (E-events). The base of the Selandian is proved to coincide with the end of the Braarudosphaera acme, which correlates with the lowest consistent occurrence (LCsO) of Lithoptychius aff. bitectus (= Fasciculithus janii sensu Steurbaut and Sztrakos, 2008) (event E4), but which is slightly posterior to the second radiation of the fasciculiths, up to now considered to represent the primary correlation tool of the DSB. A short-term δ 13 C org negative excursion, associated with an increase in p CO 2 is recorded at the very base of the Selandian. It is interpreted as a short period of global warming (hyperthermal), the duration of which is estimated at ~ 30 kyr. It is followed in all the three studied sections by a long-term decoupled carbon isotope event, marked by increasing δ 13 C org and decreasing δ 13 C carb values. It may reflect a period of climatic cooling of a few 100 kyr, interpreted as a possible precursor of the global cooling event, marking the late Paleocene in the North Atlantic realm. The integration of the biostratigraphic and the isotope data indicates major differences in sedimentation rates during the early Selandian in the studied sections, but there is no evidence of substantial breaks in sedimentation in any of the sections during this interval. The lithological shift at the base of the Selandian points to an abrupt palaeoenvironmental reorganisation, although our integrated bio-chemostratigraphical investigation does not allow for estimating its duration nor the presence of a hiatus at that time.
-
comprehensive stable isotope investigation of marine biogenic apatite from the late cretaceous early eocene phosphate series of morocco
Palaeogeography Palaeoclimatology Palaeoecology, 2014Co-Authors: Laszlό Kocsis, Johan Yans, Emmanuel Gheerbrant, Mustapha Mouflih, Henri Cappetta, Mbarek AmaghzazAbstract:Abstract Fossil biogenic apatites were studied for their geochemical composition across the late Cretaceous–early Eocene Moroccan phosphate series in the Ouled Abdoun and Ganntour basins in Morocco in order to characterize paleoenvironmental conditions and to improve stratigraphy. The vertebrate remains show particularly good structural, mineralogical and chemical preservations, which relate to the favorable depositional environment of the phosphorite. The main studied fossils – shark tooth enameloid and dentine, and coprolites – show large range in δ13C values from − 14 to + 6‰, which can be coupled to different carbon sources. Enameloid yielded mostly positive δ13C isotopic compositions that are comparable with values reported from modern teeth. Coprolites have the lowest δ13C values that reflect burial conditions with intensive organic matter recycling. The large variation in δ18OPO4 values of the shark teeth can be related to ecological differences. However, the mean δ18OPO4 data reflect important temporal variation along the series, together with the corresponding average δ13C values. Comparisons with the global isotope records allow identifying the Early Eocene Climatic Optimum in the top of the Ouled Abdoun series (above Bed 0′). The isotope data further suggest a sedimentary gap during the latest Thanetian and the Paleocene Eocene Thermal Maximum. The top of the Paleocene series (Bed IIa) can be dated to late Selandian–early Thanetian, with the recognition of the Early Late Paleocene Event (ELPE). The Eritherium Bone Bed, that yielded the earliest known placental mammals from Africa, would be located below the ELPE and therefore, cannot be younger than late Selandian. The isotope data from the older Paleocene (Bed IIb) and Cretaceous (upper Bed III) beds in the Ouled Abdoun Basin can be correlated with the latest Danian–early Selandian and the latest Maastrichtian global isotope record, respectively. Based on the δ18OPO4 data, the Cretaceous layers of the Ganntour Basin cover most of the Maastrichtian period except the very early part. All these early Paleogene and Cretaceous chemostratigraphic ages, however, need further confirmations from other proxies. Yet, the interpretations are in general agreement with the biostratigraphy derived from the selachian fauna.
-
comprehensive stable isotope investigation of marine biogenic apatite from the late cretaceous early eocene phosphate series of morocco
Palaeogeography Palaeoclimatology Palaeoecology, 2014Co-Authors: Laszlό Kocsis, Johan Yans, Emmanuel Gheerbrant, Mustapha Mouflih, Henri Cappetta, Mbarek AmaghzazAbstract:Abstract Fossil biogenic apatites were studied for their geochemical composition across the late Cretaceous–early Eocene Moroccan phosphate series in the Ouled Abdoun and Ganntour basins in Morocco in order to characterize paleoenvironmental conditions and to improve stratigraphy. The vertebrate remains show particularly good structural, mineralogical and chemical preservations, which relate to the favorable depositional environment of the phosphorite. The main studied fossils – shark tooth enameloid and dentine, and coprolites – show large range in δ13C values from − 14 to + 6‰, which can be coupled to different carbon sources. Enameloid yielded mostly positive δ13C isotopic compositions that are comparable with values reported from modern teeth. Coprolites have the lowest δ13C values that reflect burial conditions with intensive organic matter recycling. The large variation in δ18OPO4 values of the shark teeth can be related to ecological differences. However, the mean δ18OPO4 data reflect important temporal variation along the series, together with the corresponding average δ13C values. Comparisons with the global isotope records allow identifying the Early Eocene Climatic Optimum in the top of the Ouled Abdoun series (above Bed 0′). The isotope data further suggest a sedimentary gap during the latest Thanetian and the Paleocene Eocene Thermal Maximum. The top of the Paleocene series (Bed IIa) can be dated to late Selandian–early Thanetian, with the recognition of the Early Late Paleocene Event (ELPE). The Eritherium Bone Bed, that yielded the earliest known placental mammals from Africa, would be located below the ELPE and therefore, cannot be younger than late Selandian. The isotope data from the older Paleocene (Bed IIb) and Cretaceous (upper Bed III) beds in the Ouled Abdoun Basin can be correlated with the latest Danian–early Selandian and the latest Maastrichtian global isotope record, respectively. Based on the δ18OPO4 data, the Cretaceous layers of the Ganntour Basin cover most of the Maastrichtian period except the very early part. All these early Paleogene and Cretaceous chemostratigraphic ages, however, need further confirmations from other proxies. Yet, the interpretations are in general agreement with the biostratigraphy derived from the selachian fauna.
