icon
Image from Google Jackets
Image from OpenLibrary

Carbon cycle changes during the Triassic-Jurassic transition [electronic resource].

Publication details: LPP Contribution Series No.28 2010Content type:
  • نص
Media type:
  • دون وسيط
Carrier type:
  • مجلد
Subject(s): Genre/Form: DDC classification:
  • 1ST 550 C264
Online resources: Other related works: ; Summary: The end-Triassic is regarded as one of the five major mass extinction events of the Phanerozoic. This time interval is marked by up to 50% of marine biodiversity loss and major changes in terrestrial ecosystems. Mass extinction events are often marked by changes in the global carbon cycle. The reality and nature of C-cycle changes at the Triassic-Jurassic (T-J) transition are however questioned and its causes are poorly understood. Potential changes in sizes of and fluxes between exchangeable carbon reservoirs, are reflected by changes in the carbon isotopic composition of these reservoirs. Several geological outcrops, representing the T-J transition, have been studied in the Northern Calcareous Alps (Austria). Sediments in these sections were deposited in the intra-platform Eiberg Basin that extended for several hundreds of kilometers on the continental margin of the north-western Tethys Ocean. High resolution C-isotope studies in this basin showed a 5-6‰ end-Triassic carbon isotope excursion (CIE), which is directly preceded by the last occurrence of typically Triassic ammonites and succeeded by the first occurrence of typically Jurassic ammonites and pollen. This strongly suggests a simultaneous occurrence of the end-Triassic mass extinction event and the negative CIE. Compound specific delta 13C measurements on plant-wax derived n-alkanes also show a ~6‰ negative excursion together with the end-Triassic mass extinction event. It suggests global carbon cycle changes caused by 13C depleted carbon release to the atmosphere. These events have been attributed to increased volcanic CO2 emissions related to the break-up of Pangaea, and emplacement of the Central Atlantic Magmatic Province. The duration of increased volcanic activity at the T-J boundary is confined to ~600 kyr. Alternations in relative abundance of limestone versus marl and black shale deposits, are observed in the uppermost Triassic to lower Jurassic shallow marine sedimentary succession of St. Audrie’
Item type: كتاب
Tags from this library: No tags from this library for this title.
Star ratings
    Average rating: 0.0 (0 votes)

Open access content Open access content star

The end-Triassic is regarded as one of the five major mass extinction events of the Phanerozoic. This time interval is marked by up to 50% of marine biodiversity loss and major changes in terrestrial ecosystems. Mass extinction events are often marked by changes in the global carbon cycle. The reality and nature of C-cycle changes at the Triassic-Jurassic (T-J) transition are however questioned and its causes are poorly understood. Potential changes in sizes of and fluxes between exchangeable carbon reservoirs, are reflected by changes in the carbon isotopic composition of these reservoirs. Several geological outcrops, representing the T-J transition, have been studied in the Northern Calcareous Alps (Austria). Sediments in these sections were deposited in the intra-platform Eiberg Basin that extended for several hundreds of kilometers on the continental margin of the north-western Tethys Ocean. High resolution C-isotope studies in this basin showed a 5-6‰ end-Triassic carbon isotope excursion (CIE), which is directly preceded by the last occurrence of typically Triassic ammonites and succeeded by the first occurrence of typically Jurassic ammonites and pollen. This strongly suggests a simultaneous occurrence of the end-Triassic mass extinction event and the negative CIE. Compound specific delta 13C measurements on plant-wax derived n-alkanes also show a ~6‰ negative excursion together with the end-Triassic mass extinction event. It suggests global carbon cycle changes caused by 13C depleted carbon release to the atmosphere. These events have been attributed to increased volcanic CO2 emissions related to the break-up of Pangaea, and emplacement of the Central Atlantic Magmatic Province. The duration of increased volcanic activity at the T-J boundary is confined to ~600 kyr. Alternations in relative abundance of limestone versus marl and black shale deposits, are observed in the uppermost Triassic to lower Jurassic shallow marine sedimentary succession of St. Audrie’

info:eu-repo/semantics/openAccess

English