High-resolution magnetic stratigraphy at Bosso Stirpeto (Marche, Italy): Anomalous geomagnetic field behaviour during early Pliensbachian (early Jurassic) times?
We report on a high-resolution magnetostratigraphic analysis of a continuous 97.5 m thick upper Sinemurian–Pliensbachian pelagic limestone section (“Corniola” formation) exposed at Bosso Stirpeto (Marche, Italy), where detailed ammonite and calcareous nannofossil biozonation is available. The early...
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Online Access: | http://hdl.handle.net/11391/164827 https://doi.org/10.1016/j.epsl.2007.01.006 |
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ftuniperugiairis:oai:research.unipg.it:11391/164827 2023-09-05T13:19:34+02:00 High-resolution magnetic stratigraphy at Bosso Stirpeto (Marche, Italy): Anomalous geomagnetic field behaviour during early Pliensbachian (early Jurassic) times? Speranza F. PARISI, Guido Speranza, F. Parisi, Guido 2007 http://hdl.handle.net/11391/164827 https://doi.org/10.1016/j.epsl.2007.01.006 eng eng volume:256 firstpage:344 lastpage:359 journal:EARTH AND PLANETARY SCIENCE LETTERS http://hdl.handle.net/11391/164827 doi:10.1016/j.epsl.2007.01.006 magnetostratigraphy Pliensbachian Carixian Corniola formation geomagnetic field Bosso valley info:eu-repo/semantics/article 2007 ftuniperugiairis https://doi.org/10.1016/j.epsl.2007.01.006 2023-08-13T20:27:30Z We report on a high-resolution magnetostratigraphic analysis of a continuous 97.5 m thick upper Sinemurian–Pliensbachian pelagic limestone section (“Corniola” formation) exposed at Bosso Stirpeto (Marche, Italy), where detailed ammonite and calcareous nannofossil biozonation is available. The early Pliensbachian (Carixian) is notably expanded (74.35 m excluding few slumps), implying an average sedimentation rate of 28.6 m/Myr. Both the Carixian boundaries and three additional intra-Carixian ammonite zone boundaries are tied up with polarity magnetozones. We find that a normal polarity characterizes the latest Sinemurian and Sinemurian/Carixian boundary, while a reverse polarity (punctuated by three short normal polarity magnetozones) dominates the Carixian. In the lower Carixian sediments, two 3.39–4.65 m thick (excluding the slumps) intervals are characterized by persistent transitional (between 45°N and 45°S) virtual geomagnetic pole (VGP) latitudes, but this seems not to be the result of mineral magnetic artefacts, antipodal polarity averaging, or sedimentary layer disturbance. Thus we suggest that in two ∼120 and 160 kyr-long time intervals during the early Carixian, the VGPs were predominantly confined at tropical–equatorial latitudes of the Earth. Such geomagnetic feature has never been documented before elsewhere in other time intervals, and requires further paleomagnetic investigation of other expanded Carixian section to be confirmed. The magnetic polarity profile (including the transitional direction intervals) of Bosso Stirpeto may compare with that from similarly expanded Carixian sections (Breggia, Switzerland), and cores (Montcornet, Paris basin). However, the matching of magnetic polarity zones requires a significant aging of some parts of the magnetostratigraphic profile at both Breggia and Montcornet. Article in Journal/Newspaper Geomagnetic Pole IRIS Università degli Studi di Perugia Earth and Planetary Science Letters 256 3-4 344 359 |
institution |
Open Polar |
collection |
IRIS Università degli Studi di Perugia |
op_collection_id |
ftuniperugiairis |
language |
English |
topic |
magnetostratigraphy Pliensbachian Carixian Corniola formation geomagnetic field Bosso valley |
spellingShingle |
magnetostratigraphy Pliensbachian Carixian Corniola formation geomagnetic field Bosso valley Speranza F. PARISI, Guido High-resolution magnetic stratigraphy at Bosso Stirpeto (Marche, Italy): Anomalous geomagnetic field behaviour during early Pliensbachian (early Jurassic) times? |
topic_facet |
magnetostratigraphy Pliensbachian Carixian Corniola formation geomagnetic field Bosso valley |
description |
We report on a high-resolution magnetostratigraphic analysis of a continuous 97.5 m thick upper Sinemurian–Pliensbachian pelagic limestone section (“Corniola” formation) exposed at Bosso Stirpeto (Marche, Italy), where detailed ammonite and calcareous nannofossil biozonation is available. The early Pliensbachian (Carixian) is notably expanded (74.35 m excluding few slumps), implying an average sedimentation rate of 28.6 m/Myr. Both the Carixian boundaries and three additional intra-Carixian ammonite zone boundaries are tied up with polarity magnetozones. We find that a normal polarity characterizes the latest Sinemurian and Sinemurian/Carixian boundary, while a reverse polarity (punctuated by three short normal polarity magnetozones) dominates the Carixian. In the lower Carixian sediments, two 3.39–4.65 m thick (excluding the slumps) intervals are characterized by persistent transitional (between 45°N and 45°S) virtual geomagnetic pole (VGP) latitudes, but this seems not to be the result of mineral magnetic artefacts, antipodal polarity averaging, or sedimentary layer disturbance. Thus we suggest that in two ∼120 and 160 kyr-long time intervals during the early Carixian, the VGPs were predominantly confined at tropical–equatorial latitudes of the Earth. Such geomagnetic feature has never been documented before elsewhere in other time intervals, and requires further paleomagnetic investigation of other expanded Carixian section to be confirmed. The magnetic polarity profile (including the transitional direction intervals) of Bosso Stirpeto may compare with that from similarly expanded Carixian sections (Breggia, Switzerland), and cores (Montcornet, Paris basin). However, the matching of magnetic polarity zones requires a significant aging of some parts of the magnetostratigraphic profile at both Breggia and Montcornet. |
author2 |
Speranza, F. Parisi, Guido |
format |
Article in Journal/Newspaper |
author |
Speranza F. PARISI, Guido |
author_facet |
Speranza F. PARISI, Guido |
author_sort |
Speranza F. |
title |
High-resolution magnetic stratigraphy at Bosso Stirpeto (Marche, Italy): Anomalous geomagnetic field behaviour during early Pliensbachian (early Jurassic) times? |
title_short |
High-resolution magnetic stratigraphy at Bosso Stirpeto (Marche, Italy): Anomalous geomagnetic field behaviour during early Pliensbachian (early Jurassic) times? |
title_full |
High-resolution magnetic stratigraphy at Bosso Stirpeto (Marche, Italy): Anomalous geomagnetic field behaviour during early Pliensbachian (early Jurassic) times? |
title_fullStr |
High-resolution magnetic stratigraphy at Bosso Stirpeto (Marche, Italy): Anomalous geomagnetic field behaviour during early Pliensbachian (early Jurassic) times? |
title_full_unstemmed |
High-resolution magnetic stratigraphy at Bosso Stirpeto (Marche, Italy): Anomalous geomagnetic field behaviour during early Pliensbachian (early Jurassic) times? |
title_sort |
high-resolution magnetic stratigraphy at bosso stirpeto (marche, italy): anomalous geomagnetic field behaviour during early pliensbachian (early jurassic) times? |
publishDate |
2007 |
url |
http://hdl.handle.net/11391/164827 https://doi.org/10.1016/j.epsl.2007.01.006 |
genre |
Geomagnetic Pole |
genre_facet |
Geomagnetic Pole |
op_relation |
volume:256 firstpage:344 lastpage:359 journal:EARTH AND PLANETARY SCIENCE LETTERS http://hdl.handle.net/11391/164827 doi:10.1016/j.epsl.2007.01.006 |
op_doi |
https://doi.org/10.1016/j.epsl.2007.01.006 |
container_title |
Earth and Planetary Science Letters |
container_volume |
256 |
container_issue |
3-4 |
container_start_page |
344 |
op_container_end_page |
359 |
_version_ |
1776200362334617600 |