Oolites from the Arabian platform: Archives for the aftermath of the end-Triassic mass extinction
(2021) In Dissertations in Geology at Lund University, Master’s thesis GEOR02 20211Department of Geology
- Abstract
- The end-Triassic mass extinction (ETME) which occurred around 201 Ma is known as one of “the big five” mass extinction events of the Phanerozoic eon. Its effects were most severe on marine ecosystems, resulting in a global decline of invertebrate taxa and the complete extinction of the conodonts. The cause of the ETME can be attributed to the volcanic activity of the Central Atlantic magmatic province (CAMP), which resulted in drastic emissions of volcanogenic gasses such as CO2 and SO2. These eruptions caused severe environmental changes such as global warming and ocean acidification, which made the ETME particularly selective for acid sensitive taxa. These conditions also resulted in an almost global depositional hiati at the time of the... (More)
- The end-Triassic mass extinction (ETME) which occurred around 201 Ma is known as one of “the big five” mass extinction events of the Phanerozoic eon. Its effects were most severe on marine ecosystems, resulting in a global decline of invertebrate taxa and the complete extinction of the conodonts. The cause of the ETME can be attributed to the volcanic activity of the Central Atlantic magmatic province (CAMP), which resulted in drastic emissions of volcanogenic gasses such as CO2 and SO2. These eruptions caused severe environmental changes such as global warming and ocean acidification, which made the ETME particularly selective for acid sensitive taxa. These conditions also resulted in an almost global depositional hiati at the time of the Triassic – Jurassic boundary.
In this study, marine strata from the Triassic – Jurassic boundary interval at Wadi Ghalilah in the United Arab Emirates have been petrographically and geochemically analysed. The examined strata are part of the Ghalilah Formation, namely the uppermost Sumra (Rhaetian) and the Sakhra (Hettangian) Members. The study had the goal to describe the geological, geochemical, and environmental conditions present after the ETME. Results were also compared with other Triassic—Jurassic boundary sections in order to understand the effects of the ETME on global and regional scales.
Through the analyses conducted in this study, it seems evident that the ocean acidification caused by CAMP was indeed widespread enough to affect the southern latitudes of the UAE at the time. This can be seen in the form of a submarine dissolution surface and subsequent deposition of oolites and microbialites as anachronistic facies. The globally recognized Hettangian transgressions are also supported from Wadi Ghalilah, and was likely strongly influenced by the disappearance of carbonate producing organisms. Analyses of major, trace, and rare earth elements in ooids indicate a slight increase in anoxia after the onset of the Hettangian, as well as increased continental weathering which could be coupled with the start of increased biological productivity after the extinction. (Less) - Abstract (Swedish)
- Det sen-Triassiska massutdöendet (STM) som inträffade för omkring 201 miljoner år sedan är känt som ett av ”de fem stora” massutdöendena under Fanerozoisk tid. Massutdöendet påverkade främst marina ekosystem, vilket resulterade i en global minskning av ryggradslösa djur och utdöendet av konodonterna. Orsaken till STM kan anknytas till utbrotten av den Central-Atlantiska magmatiska provinsen (CAMP), vars utsläpp av vulkanogena gaser såsom koldioxid och svaveldioxid resulterade i drastiska miljöförändringar såsom global uppvärmning och försurning av haven. Detta medförde att organismer som var speciellt känsliga för låga pH-nivåer drabbades hårdast. Dessutom orsakade denna försurning avbrott i depositionen av karbonater under den Triassiska... (More)
- Det sen-Triassiska massutdöendet (STM) som inträffade för omkring 201 miljoner år sedan är känt som ett av ”de fem stora” massutdöendena under Fanerozoisk tid. Massutdöendet påverkade främst marina ekosystem, vilket resulterade i en global minskning av ryggradslösa djur och utdöendet av konodonterna. Orsaken till STM kan anknytas till utbrotten av den Central-Atlantiska magmatiska provinsen (CAMP), vars utsläpp av vulkanogena gaser såsom koldioxid och svaveldioxid resulterade i drastiska miljöförändringar såsom global uppvärmning och försurning av haven. Detta medförde att organismer som var speciellt känsliga för låga pH-nivåer drabbades hårdast. Dessutom orsakade denna försurning avbrott i depositionen av karbonater under den Triassiska – Jurassiska övergången på ett flertal platser globalt.
I denna studie har marina avlagringar från slutet av trias och början av jura från Wadi Ghalilah i Förenade Arabemiraten petrografiskt och geokemiskt analyserats. Det undersökta intervallet ingår i Ghalilahformationen och består av översta delen av Sumraledet (rät) och Sakhraledet (hettang). Målet med undersökningarna har varit att beskriva de geologiska och geokemiska förhållandena som rådde efter STM. Resultaten har även jämförts med andra likåldriga avlagringar för att få en uppfattning om hur omfattande påverkningarna av STM har varit på global och regional skala.
Analyserna som utförts i denna studie tyder på att försurningen av havet måste varit omfattande nog för att också påverka de tropiska breddgraderna där Wadi Ghalilah en gång låg. Detta kan ses i form av marina upplösningsytor och efterföljande deposition av ooliter of mikrober i form av anakronistiska facies. De globalt igenkänningsbara transgressioner som förekom under hettang kan även observeras vid Wadi Ghalilah, och var sannolikt påverkade i hög grad av försvinnandet av karbonatproducerande organismer. Analyser av grund- och spårämnen samt sällsynta jordartsmetaller i ooider indikerar en lätt ökning av syrefattiga förhållanden efter början av hettang, samt ökad kontinental vittring vilket skulle kunna kopplas till början av en långsam ökning av biologisk produktivitet efter massutdöendet. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9052910
- author
- Greiff, Johannes LU
- supervisor
-
- Sylvain Richoz LU
- Ingrid Urban LU
- organization
- alternative title
- Ooliter från Arabiska plattformen: Arkiv för efterföljderna av det sen-Triassiska massutdöendet
- course
- GEOR02 20211
- year
- 2021
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- sedimentology, carbonates, geochemistry, oolites, ooids, thrombolites, microbialites, Triassic, Jurassic, Hettangian, extinction, United Arab Emirates, Wadi Ghalilah, Wadi Milaha
- publication/series
- Dissertations in Geology at Lund University, Master’s thesis
- report number
- 616
- language
- English
- id
- 9052910
- date added to LUP
- 2021-06-11 11:13:35
- date last changed
- 2021-06-11 11:13:35
@misc{9052910,
abstract = {{The end-Triassic mass extinction (ETME) which occurred around 201 Ma is known as one of “the big five” mass extinction events of the Phanerozoic eon. Its effects were most severe on marine ecosystems, resulting in a global decline of invertebrate taxa and the complete extinction of the conodonts. The cause of the ETME can be attributed to the volcanic activity of the Central Atlantic magmatic province (CAMP), which resulted in drastic emissions of volcanogenic gasses such as CO2 and SO2. These eruptions caused severe environmental changes such as global warming and ocean acidification, which made the ETME particularly selective for acid sensitive taxa. These conditions also resulted in an almost global depositional hiati at the time of the Triassic – Jurassic boundary.
In this study, marine strata from the Triassic – Jurassic boundary interval at Wadi Ghalilah in the United Arab Emirates have been petrographically and geochemically analysed. The examined strata are part of the Ghalilah Formation, namely the uppermost Sumra (Rhaetian) and the Sakhra (Hettangian) Members. The study had the goal to describe the geological, geochemical, and environmental conditions present after the ETME. Results were also compared with other Triassic—Jurassic boundary sections in order to understand the effects of the ETME on global and regional scales.
Through the analyses conducted in this study, it seems evident that the ocean acidification caused by CAMP was indeed widespread enough to affect the southern latitudes of the UAE at the time. This can be seen in the form of a submarine dissolution surface and subsequent deposition of oolites and microbialites as anachronistic facies. The globally recognized Hettangian transgressions are also supported from Wadi Ghalilah, and was likely strongly influenced by the disappearance of carbonate producing organisms. Analyses of major, trace, and rare earth elements in ooids indicate a slight increase in anoxia after the onset of the Hettangian, as well as increased continental weathering which could be coupled with the start of increased biological productivity after the extinction.}},
author = {{Greiff, Johannes}},
language = {{eng}},
note = {{Student Paper}},
series = {{Dissertations in Geology at Lund University, Master’s thesis}},
title = {{Oolites from the Arabian platform: Archives for the aftermath of the end-Triassic mass extinction}},
year = {{2021}},
}