Selected Famennian (Late Devonian) events (Condroz, Annulata, Hangenberg) in Sardinia and in the Carnic Alps: conodont biostratigraphy, magnetic susceptibility and geochemistry.
type: CreativeWork
description: The Condroz, the Annulata and the Hangenberg are three events occurred in the Famennian. Causes and consequences are different for each one. The Condroz event is related to a sharp regression associated with an extinction of few ammonoid groups. The Annulata event to a transgression associated with a global spread of the ammonoid Platyclymeniae annulata. The Hangenberg event is a major event, that took place in a complex phase of eustatic variations that affected severely the fauna, and it is considered as one of the biggest extinction in the history of the earth. A multidisciplinary approach is here provided to investigate the selected events. A biostratigraphic study based on conodonts was carried out to individuate the precise biostratigraphic position when the events occurred. The evolution of the low field magnetic susceptibility and the major elements geochemistry (Al, Si, K and Ti) have been investigated to study the evolution of the detrital input across the events. Six different section were studied in two different areas of North Gondwana where the Famennian rocks are well exposed. Two sections bearing the Condroz and the Annulata events were studied in the Carnic Alps, four sections containing the three events were studied in the South East of Sardinia. A detailed biostratigraphic study is here provided from both areas. More than 28 000 conodonts have been collected and discriminated into 101 taxa. Each taxon is described and illustrated. Ten conodont Zones, from the Upper rhenana Zone (Frasnian) to the Lower expansa Zone (Famennian) have been recognized in the Carnic Alps. Nineteen conodont Zones, from the Lower crepida Zone (Famennian) to the Upper duplicata Zone (Tournaisian) have been discriminated in the Sardinian sections. The three events have been recognized in both areas. As for the Condroz and for the Annulata events, even if there is no change in lithology, the curves obtained by the MS and the major elements tends to show distinctive peaks tim…
abstract: The Condroz, the Annulata and the Hangenberg are three events occurred in the Famennian. Causes and consequences are different for each one. The Condroz event is related to a sharp regression associated with an extinction of few ammonoid groups. The Annulata event to a transgression associated with a global spread of the ammonoid Platyclymeniae annulata. The Hangenberg event is a major event, that took place in a complex phase of eustatic variations that affected severely the fauna, and it is considered as one of the biggest extinction in the history of the earth. A multidisciplinary approach is here provided to investigate the selected events. A biostratigraphic study based on conodonts was carried out to individuate the precise biostratigraphic position when the events occurred. The evolution of the low field magnetic susceptibility and the major elements geochemistry (Al, Si, K and Ti) have been investigated to study the evolution of the detrital input across the events. Six different section were studied in two different areas of North Gondwana where the Famennian rocks are well exposed. Two sections bearing the Condroz and the Annulata events were studied in the Carnic Alps, four sections containing the three events were studied in the South East of Sardinia. A detailed biostratigraphic study is here provided from both areas. More than 28 000 conodonts have been collected and discriminated into 101 taxa. Each taxon is described and illustrated. Ten conodont Zones, from the Upper rhenana Zone (Frasnian) to the Lower expansa Zone (Famennian) have been recognized in the Carnic Alps. Nineteen conodont Zones, from the Lower crepida Zone (Famennian) to the Upper duplicata Zone (Tournaisian) have been discriminated in the Sardinian sections. The three events have been recognized in both areas. As for the Condroz and for the Annulata events, even if there is no change in lithology, the curves obtained by the MS and the major elements tends to show distinctive peaks tim…
author: MOSSONI, ANGELO
language: eng
keywords: Biostratigrafia, annulata, biostratigrafy, condroz, conodonti, conodonts, devonian/carboniferous, devoniano/carbonifero, eventi, events, famennian, famenniano, hangenberg, magnetic susceptibility, suscettività magnetica, Settore GEO/01 - Paleontologia e Paleoecologia
date published: 2015-03-27
date modified: 2026-07-24T01:30:05Z
provider: Università di Cagliari
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Università degli Studi di Cagliari

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property ID: Handle
value: http://hdl.handle.net/11584/266566