Luke Faggetter | University of Leeds (original) (raw)
Address: Luke Faggetter, ESSI Postgraduate PhD Student
Room 7.131
School of Earth and Environment
University of Leeds,
LS2 9JT
Homepage: https://www.pdr.leeds.ac.uk/web.php?pg=ee08lef
Cohen Geochemistry Research Group: http://www.see.leeds.ac.uk/research/essi/cohen-research-group/
The Palaeo@Leeds Research Group: http://www.see.leeds.ac.uk/research/essi/palaeoleeds/
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Papers by Luke Faggetter
AGU Fall Meeting Abstracts, Dec 1, 2018
Table containing stratigraphic and geochemical data. Rows coloured in grey indicate samples exclu... more Table containing stratigraphic and geochemical data. Rows coloured in grey indicate samples excluded due to low TOC (< 0.01 wt% TOC). Rows coloured in orange indicate the extinction horizon at Oak Springs Summit and Ruin Wash.
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Palaeogeography, Palaeoclimatology, Palaeoecology, 2017
Geological Magazine, 2016
Globally, the Series 2 – Series 3 boundary of the Cambrian System coincides with a major carbon i... more Globally, the Series 2 – Series 3 boundary of the Cambrian System coincides with a major carbon isotope excursion, sea-level changes and trilobite extinctions. Here we examine the sedimentology, sequence stratigraphy and carbon isotope record of this interval in the Cambrian strata (Durness Group) of NW Scotland. Carbonate carbon isotope data from the lower part of the Durness Group (Ghrudaidh Formation) show that the shallow-marine, Laurentian margin carbonates record two linked sea-level and carbon isotopic events. Whilst the carbon isotope excursions are not as pronounced as those expressed elsewhere, correlation with global records (Sauk I – Sauk II boundary andOlenellusbiostratigraphic constraint) identifies them as representing the local expression of the ROECE and DICE. The upper part of the ROECE is recorded in the basal Ghrudaidh Formation whilst the DICE is seen around 30m above the base of this unit. Both carbon isotope excursions co-occur with surfaces interpreted to rec...
The mass extinction of the olenellid trilobites occurred around the Cambrian Series 2–Series 3 bo... more The mass extinction of the olenellid trilobites occurred around the Cambrian Series 2–Series 3 boundary. Like many other crises, it coincided with a negative carbon isotope excursion but the associated palaeoenvironmental changes remain unclear. To investigate the causal mechanism for this event, we report facies changes, pyrite framboid petrography and carbon isotope values from Cambrian Series 2–Series 3 (traditionally Early–Middle Cambrian) boundary strata of the Carrara Formation (Death Valley region, California) and Pioche Formation (Nevada). These data reveal regionally changing water depths from high-energy, nearshore facies (oolitic grainstone) to more offshore silty marl and finer-grained carbonate mudstone. In the Carrara Formation, the series boundary occurs within a deepening succession, transitioning from high-energy, nearshore facies (oolitic grainstone and oncolitic packstone) to offshore marl, the latter of which contains pyrite framboid populations indicative of low-oxygen (dysoxic) depositional conditions. Intermittent dysoxia persisted below sub-wave base settings throughout the early and middle Cambrian, but did not intensify at the time of extinction, arguing against anoxia as a primary cause in the olenellid trilobite extinction. Within both field areas, the extinction interval coincided with a minimum in δ 13 C carb values, which we interpret as the regional manifestation of the Redlichiid-Olenellid Extinction Carbon isotope Excursion (ROECE). The Series 2–Series 3 boundary is reported to closely coincide with a large-amplitude sea-level fall that produced the Sauk I/II sequence boundary, but the placement of the Series 2–Series 3 boundary within a transgressive interval of the Carrara Formation shows that this is not the case.The main sequence boundary in the succession occurs much lower in the succession (at the top of the Zabriskie Quartzite) and therefore precedes the extinction of the olenellids and ROECE.
– Globally, the Series 2 – Series 3 boundary of the Cambrian System coincides with a major carbon... more – Globally, the Series 2 – Series 3 boundary of the Cambrian System coincides with a major carbon isotope excursion, sea-level changes and trilobite extinctions. Here we examine the sedimentology, sequence stratigraphy and carbon isotope record of this interval in the Cambrian strata (Durness Group) of NW Scotland. Carbonate carbon isotope data from the lower part of the Durness Group (Ghrudaidh Formation) show that the shallow-marine, Laurentian margin carbonates record two linked sea-level and carbon isotopic events. Whilst the carbon isotope excursions are not as pronounced as those expressed elsewhere, correlation with global records (Sauk I – Sauk II boundary and Olenellus biostratigraphic constraint) identifies them as representing the local expression of the ROECE and DICE. The upper part of the ROECE is recorded in the basal Ghrudaidh Formation whilst the DICE is seen around 30 m above the base of this unit. Both carbon isotope excursions co-occur with surfaces interpreted to record regressive–transgressive events that produced amalgamated sequence boundaries and ravinement/flooding surfaces overlain by conglomerates of reworked intraclasts. The ROECE has been linked with redlichiid and olenellid trilobite extinctions, but in NW Scotland, Olenellus is found after the negative peak of the carbon isotope excursion but before sequence boundary formation.
Conference Presentations by Luke Faggetter
AGU Fall Meeting Abstracts, Dec 1, 2018
Table containing stratigraphic and geochemical data. Rows coloured in grey indicate samples exclu... more Table containing stratigraphic and geochemical data. Rows coloured in grey indicate samples excluded due to low TOC (< 0.01 wt% TOC). Rows coloured in orange indicate the extinction horizon at Oak Springs Summit and Ruin Wash.
[
Palaeogeography, Palaeoclimatology, Palaeoecology, 2017
Geological Magazine, 2016
Globally, the Series 2 – Series 3 boundary of the Cambrian System coincides with a major carbon i... more Globally, the Series 2 – Series 3 boundary of the Cambrian System coincides with a major carbon isotope excursion, sea-level changes and trilobite extinctions. Here we examine the sedimentology, sequence stratigraphy and carbon isotope record of this interval in the Cambrian strata (Durness Group) of NW Scotland. Carbonate carbon isotope data from the lower part of the Durness Group (Ghrudaidh Formation) show that the shallow-marine, Laurentian margin carbonates record two linked sea-level and carbon isotopic events. Whilst the carbon isotope excursions are not as pronounced as those expressed elsewhere, correlation with global records (Sauk I – Sauk II boundary andOlenellusbiostratigraphic constraint) identifies them as representing the local expression of the ROECE and DICE. The upper part of the ROECE is recorded in the basal Ghrudaidh Formation whilst the DICE is seen around 30m above the base of this unit. Both carbon isotope excursions co-occur with surfaces interpreted to rec...
The mass extinction of the olenellid trilobites occurred around the Cambrian Series 2–Series 3 bo... more The mass extinction of the olenellid trilobites occurred around the Cambrian Series 2–Series 3 boundary. Like many other crises, it coincided with a negative carbon isotope excursion but the associated palaeoenvironmental changes remain unclear. To investigate the causal mechanism for this event, we report facies changes, pyrite framboid petrography and carbon isotope values from Cambrian Series 2–Series 3 (traditionally Early–Middle Cambrian) boundary strata of the Carrara Formation (Death Valley region, California) and Pioche Formation (Nevada). These data reveal regionally changing water depths from high-energy, nearshore facies (oolitic grainstone) to more offshore silty marl and finer-grained carbonate mudstone. In the Carrara Formation, the series boundary occurs within a deepening succession, transitioning from high-energy, nearshore facies (oolitic grainstone and oncolitic packstone) to offshore marl, the latter of which contains pyrite framboid populations indicative of low-oxygen (dysoxic) depositional conditions. Intermittent dysoxia persisted below sub-wave base settings throughout the early and middle Cambrian, but did not intensify at the time of extinction, arguing against anoxia as a primary cause in the olenellid trilobite extinction. Within both field areas, the extinction interval coincided with a minimum in δ 13 C carb values, which we interpret as the regional manifestation of the Redlichiid-Olenellid Extinction Carbon isotope Excursion (ROECE). The Series 2–Series 3 boundary is reported to closely coincide with a large-amplitude sea-level fall that produced the Sauk I/II sequence boundary, but the placement of the Series 2–Series 3 boundary within a transgressive interval of the Carrara Formation shows that this is not the case.The main sequence boundary in the succession occurs much lower in the succession (at the top of the Zabriskie Quartzite) and therefore precedes the extinction of the olenellids and ROECE.
– Globally, the Series 2 – Series 3 boundary of the Cambrian System coincides with a major carbon... more – Globally, the Series 2 – Series 3 boundary of the Cambrian System coincides with a major carbon isotope excursion, sea-level changes and trilobite extinctions. Here we examine the sedimentology, sequence stratigraphy and carbon isotope record of this interval in the Cambrian strata (Durness Group) of NW Scotland. Carbonate carbon isotope data from the lower part of the Durness Group (Ghrudaidh Formation) show that the shallow-marine, Laurentian margin carbonates record two linked sea-level and carbon isotopic events. Whilst the carbon isotope excursions are not as pronounced as those expressed elsewhere, correlation with global records (Sauk I – Sauk II boundary and Olenellus biostratigraphic constraint) identifies them as representing the local expression of the ROECE and DICE. The upper part of the ROECE is recorded in the basal Ghrudaidh Formation whilst the DICE is seen around 30 m above the base of this unit. Both carbon isotope excursions co-occur with surfaces interpreted to record regressive–transgressive events that produced amalgamated sequence boundaries and ravinement/flooding surfaces overlain by conglomerates of reworked intraclasts. The ROECE has been linked with redlichiid and olenellid trilobite extinctions, but in NW Scotland, Olenellus is found after the negative peak of the carbon isotope excursion but before sequence boundary formation.