Publication Date:
2022-05-04
Description:
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.
Description:
Published
Description:
220-243
Description:
2.2. Laboratorio di paleomagnetismo
Description:
JCR Journal
Description:
reserved
Keywords:
Chronostratigraphy
;
Cyclostratigraphy
;
pelagic succession
;
sea-level fall
;
04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport
;
04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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