The Experts below are selected from a list of 39 Experts worldwide ranked by ideXlab platform
Robert S. Nicoll - One of the best experts on this subject based on the ideXlab platform.
-
age of the yarrabee and accessory tuffs implications for the upper Permian Sediment accumulation rates across the bowen basin
Australian Journal of Earth Sciences, 2016Co-Authors: S A Ayaz, Yuri Amelin, J S Esterle, M. Martin, Robert S. NicollAbstract:The Yarrabee Tuff is a stratigraphically significant marker across the Bowen Basin separating the Fort Cooper–Burngrove–Fair Hill formations from the overlying Rangal and equivalent coal measures. At least three to four persistent tuffs (referred here as accessary tuffs) beneath the Yarrabee Tuff were recognised in the Fort Cooper Coal Measures as suitable for regional stratigraphic correlations. In this study, we determined the ages of the Yarrabee and accessary tuffs across different morphotectonic zones of the basin through high-precision U–Pb dating of zircon with the CA-IDTIMS technique. The age of the Yarrabee Tuff is found to be 252.69 ± 0.16 Ma in the Duckworth 11 well, 253.07 ± 0.22 Ma in the Crocker Gully 2 well and <252.58 ± 0.23 Ma in the Peat 1 well. The age range of the Yarrabee Tuff coincides with the previously published date of the Kaloola Tuff Member in Meeleebee 5 suggesting that the tuffs are stratigraphically equivalent. The age range for the accessory tuff 1 is 253.12 ± 0.12 Ma to 252.85 ± 0.16 Ma, 253.45 ± 0.08 Ma for accessory tuff 2 and 253.77 ± 0.17 Ma to 253.57± 0.18 Ma for accessory tuff 3, placing them in the upper Changhsingian Stage. The age of the accessory tuff 6 (less laterally consistent in the basin) from the Fair Hill Formation is 254.03 ± 0.03 Ma, placing it in the lower Changhsingian Stage. The age-constrained intervals allow the estimation of Sedimentation rates using decompacted coal and clastic Sediment thickness. In the Taroom Trough, the temporal variation in Sedimentation rates is found to be 902 m/Ma in the Fair Hill Formation decreasing to 234.5 m/Ma in the overlying Burngrove Formation, reflecting a decrease in accommodation or Sediment supply upwards in the sequence. Across the basin, the Sedimentation rates for the Burngrove Formation are consistently higher in the Taroom Trough ranging between 234.5 and 224.5 m/Ma and lower rates of 112 m/Ma in the Roma Shelf. This regional variation reflects areas of high Sedimentation rates that are high accommodation sites recognised by split coal seams and increased interburden. Conversely, low Sedimentation rates reflect low accommodation sites, such as the Roma Shelf and the Burunga Anticline that are characterised by coalesced coal seams. The results help to understand stratal relationships across variable accommodation sites, basin-fill history of the basin including extent of Sediment supply and paleotopographic controls during the evolution of the Bowen Basin. We also discuss criteria for interpreting the results of CA-IDTIMS U–Pb dating and consider the possible geological uncertainties related to either the primary magmatic processes or secondary reworking of tuffs at the site of deposition.
-
Age of the Yarrabee and accessory tuffs: implications for the upper Permian Sediment-accumulation rates across the Bowen Basin
Australian Journal of Earth Sciences, 2016Co-Authors: S A Ayaz, Yuri Amelin, M. Martin, Robert S. NicollAbstract:The Yarrabee Tuff is a stratigraphically significant marker across the Bowen Basin separating the Fort Cooper–Burngrove–Fair Hill formations from the overlying Rangal and equivalent coal measures. At least three to four persistent tuffs (referred here as accessary tuffs) beneath the Yarrabee Tuff were recognised in the Fort Cooper Coal Measures as suitable for regional stratigraphic correlations. In this study, we determined the ages of the Yarrabee and accessary tuffs across different morphotectonic zones of the basin through high-precision U–Pb dating of zircon with the CA-IDTIMS technique. The age of the Yarrabee Tuff is found to be 252.69 ± 0.16 Ma in the Duckworth 11 well, 253.07 ± 0.22 Ma in the Crocker Gully 2 well and
S A Ayaz - One of the best experts on this subject based on the ideXlab platform.
-
age of the yarrabee and accessory tuffs implications for the upper Permian Sediment accumulation rates across the bowen basin
Australian Journal of Earth Sciences, 2016Co-Authors: S A Ayaz, Yuri Amelin, J S Esterle, M. Martin, Robert S. NicollAbstract:The Yarrabee Tuff is a stratigraphically significant marker across the Bowen Basin separating the Fort Cooper–Burngrove–Fair Hill formations from the overlying Rangal and equivalent coal measures. At least three to four persistent tuffs (referred here as accessary tuffs) beneath the Yarrabee Tuff were recognised in the Fort Cooper Coal Measures as suitable for regional stratigraphic correlations. In this study, we determined the ages of the Yarrabee and accessary tuffs across different morphotectonic zones of the basin through high-precision U–Pb dating of zircon with the CA-IDTIMS technique. The age of the Yarrabee Tuff is found to be 252.69 ± 0.16 Ma in the Duckworth 11 well, 253.07 ± 0.22 Ma in the Crocker Gully 2 well and <252.58 ± 0.23 Ma in the Peat 1 well. The age range of the Yarrabee Tuff coincides with the previously published date of the Kaloola Tuff Member in Meeleebee 5 suggesting that the tuffs are stratigraphically equivalent. The age range for the accessory tuff 1 is 253.12 ± 0.12 Ma to 252.85 ± 0.16 Ma, 253.45 ± 0.08 Ma for accessory tuff 2 and 253.77 ± 0.17 Ma to 253.57± 0.18 Ma for accessory tuff 3, placing them in the upper Changhsingian Stage. The age of the accessory tuff 6 (less laterally consistent in the basin) from the Fair Hill Formation is 254.03 ± 0.03 Ma, placing it in the lower Changhsingian Stage. The age-constrained intervals allow the estimation of Sedimentation rates using decompacted coal and clastic Sediment thickness. In the Taroom Trough, the temporal variation in Sedimentation rates is found to be 902 m/Ma in the Fair Hill Formation decreasing to 234.5 m/Ma in the overlying Burngrove Formation, reflecting a decrease in accommodation or Sediment supply upwards in the sequence. Across the basin, the Sedimentation rates for the Burngrove Formation are consistently higher in the Taroom Trough ranging between 234.5 and 224.5 m/Ma and lower rates of 112 m/Ma in the Roma Shelf. This regional variation reflects areas of high Sedimentation rates that are high accommodation sites recognised by split coal seams and increased interburden. Conversely, low Sedimentation rates reflect low accommodation sites, such as the Roma Shelf and the Burunga Anticline that are characterised by coalesced coal seams. The results help to understand stratal relationships across variable accommodation sites, basin-fill history of the basin including extent of Sediment supply and paleotopographic controls during the evolution of the Bowen Basin. We also discuss criteria for interpreting the results of CA-IDTIMS U–Pb dating and consider the possible geological uncertainties related to either the primary magmatic processes or secondary reworking of tuffs at the site of deposition.
-
Age of the Yarrabee and accessory tuffs: implications for the upper Permian Sediment-accumulation rates across the Bowen Basin
Australian Journal of Earth Sciences, 2016Co-Authors: S A Ayaz, Yuri Amelin, M. Martin, Robert S. NicollAbstract:The Yarrabee Tuff is a stratigraphically significant marker across the Bowen Basin separating the Fort Cooper–Burngrove–Fair Hill formations from the overlying Rangal and equivalent coal measures. At least three to four persistent tuffs (referred here as accessary tuffs) beneath the Yarrabee Tuff were recognised in the Fort Cooper Coal Measures as suitable for regional stratigraphic correlations. In this study, we determined the ages of the Yarrabee and accessary tuffs across different morphotectonic zones of the basin through high-precision U–Pb dating of zircon with the CA-IDTIMS technique. The age of the Yarrabee Tuff is found to be 252.69 ± 0.16 Ma in the Duckworth 11 well, 253.07 ± 0.22 Ma in the Crocker Gully 2 well and
Jean Broutin - One of the best experts on this subject based on the ideXlab platform.
-
The Permian-Triassic transition and the onset of the Mesozoic Sedimentation at the northwestern peri-Tethyan domain scale : Paleogeographic maps and geodynamic implications
Palaeogeography Palaeoclimatology Palaeoecology, 2011Co-Authors: Sylvie Bourquin, Antoine Bercovici, José López-gómez, J.b. Diez, Jean BroutinAbstract:The main aim of this paper is to review Middle Permian through Middle Triassic continental successions in European. Secondly, areas of MiddleLate Permian Sedimentation, the PermianTriassic Boundary (PTB) and the onset of Triassic Sedimentation at the scale of the westernmost peri-Tethyan domain are defined in order to construct palaeogeographic maps of the area and to discuss the impact of tectonics, climate and Sediment supply on the preservation of continental Sediment. At the scale of the western European peri-Tethyan basins, the Upper Permian is characterised by a general progradational pattern from playa-lake or floodplain to fluvial environments. In the northern Variscan Belt domain, areas of Sedimentation were either isolated or connected to the large basin, which was occupied by the Zechstein Sea. In the southern Variscan Belt, during the Late Permian, either isolated endoreic basins occurred, with palaeocurrent directions indicating local sources, or basins underwent erosion and/or there was no deposition. These basins were not connected with the Tethys Ocean, which could be explained by a high border formed by CorsicaSardinia palaeorelief and even parts of the Kabilia microplate. The palaeoflora and Sedimentary environments suggest warm and semi-arid climatic conditions. At the scale of the whole study area, an unconformity (more or less angular) is observed almost everywhere between deposits of the Upper Permian and Triassic, except in the central part of the Germanic Basin. The Sedimentation gap is more developed in the southern area where, in some basins, Upper Permian Sediment does not occur. The large Sedimentary supply, erosion and/or lack of deposition during the Late Permian, as well as the variable palaeocurrent direction pattern between the MiddleLate Permian and the Early Triassic indicate a period of relief rejuvenation during the Late Permian. During the Induan, all the intra-belt basins were under erosion and Sediment was only preserved in the extra-belt domains (the northern and extreme southern domains). In the northern domain (the central part of the Germanic Basin), Sediment was preserved under the same climatic conditions as during the latest Permian, whereas in the extreme southern domain, it was probably preserved in the Tethys Ocean, implying a large amount of detrital components entering the marine waters. Mesozoic Sedimentation began in the early Olenekian; the ephemeral fluvial systems indicate arid climatic conditions during this period. Three distinct areas of Sedimentation occur: a northern and southern domain, separated by an intra-belt domain. The latter accumulated Sediments during the EarlyMiddle Permian and experienced erosion and/or no-deposition conditions between the MiddleLate Permian and the beginning of Mesozoic Sedimentation, dated as Anisian to Hettangian. At the top of the Lower Triassic, another tectonically induced, more or less angular unconformity is observed: the Hardegsen unconformity, which is dated as intra-Spathian and is especially found in the North European basins. This tectonic activity created new source areas and a new fluvial style, with marine influences at the distal part of the systems. During the Anisian and Ladinian, continental Sedimentation was characterised by a retrogradational trend. In other words, the fluvial system evolved into fluvio-marine environments, attesting to a direct influence of the Tethys Ocean in the southern and northern domains. Both at the end of the Olenekian (Spathian) and during the Anisian, the presence of palaeosols, micro- and macrofloras indicate less arid conditions throughout this domain.
Roberto Malaroda - One of the best experts on this subject based on the ideXlab platform.
-
The pseudoporphyric gneisses of the Gordolasque and upper Merveilles valleys (Alpes-Maritimes, France)
Rendiconti Lincei, 1996Co-Authors: Roberto MalarodaAbstract:This third Memoir completes the description of the pseudoporphyric gneisses of Southern Argentera. It deals with the area between the two previously examined, where these gneisses are abundant and mostly in contact or very near to Permian Sediment outcrops. Special attention is therefore devoted to Sediments, metamorphites and migmatites, and their relationships with our rock. An exhaustive account is presented of what can be seen in the field and under microscope, and the results of chemical and microchemical analyses. La Memoria esamina la distribuzione del nuovo litotipo nella Valle Gordolasque (bacino della Vesubie) e nell’alta Valle delle Meraviglie (bacino della Roia) concludendo le segnalazioni di questa roccia che è esclusiva della parte meridionale dell Massiccio Cristallino dell’Argentera (Alpes-Maritimes, Francia). Nel presente lavoro è particolarmente documentata la derivazione del litotipo da rocce Sedimentarie clastiche e sono descritti i rapporti stratigrafic con le formazioni Permiane.
-
The pseudoporphyric gneisses of the Gordolasque and upper Merveilles valleys (Alpes-Maritimes, France)
Rendiconti Lincei, 1996Co-Authors: Roberto MalarodaAbstract:This thirdMemoir completes the description of the pseudoporphyric gneisses of Southern Argentera. It deals with the area between the two previously examined, where these gneisses are abundant and mostly in contact or very near to Permian Sediment outcrops. Special attention is therefore devoted to Sediments, metamorphites and migmatites, and their relationships with our rock. An exhaustive account is presented of what can be seen in the field and under microscope, and the results of chemical and microchemical analyses.
Mark A. Sephton - One of the best experts on this subject based on the ideXlab platform.
-
Oxygen-containing aromatic compounds in a Late Permian Sediment
Organic Geochemistry, 2005Co-Authors: Jonathan S. Watson, Mark A. Sephton, Cindy V. Looy, Iain GilmourAbstract:In northern Italy the base of the Tesero Oolite Horizon represents the lithological boundary between the Bellerophon and Werfen Formations and marks one of the most dramatic environmental perturbations in Phanerozoic time. The marl, which directly underlies the Tesero Horizon, contains many indicators of environmental change during the end-Permian mass extinction. At Vigo Meano, near Trento, the marl is relatively thermally immature and contains abundant terrestrially-sourced oxygen containing aromatic compounds such as xanthones, dibenzofurans and dibenzo-p-dioxin as well as abundant alkylated naphthalenes.
-
Cyclic diaryl ethers in a Late Permian Sediment
Organic Geochemistry, 1999Co-Authors: Mark A. Sephton, Cindy V. Looy, Ruben J. Veefkind, Henk Visscher, Henk Brinkhuis, J.w. De LeeuwAbstract:Abstract Abundant cyclic diaryl ethers, such as dibenzofuran and its alkyl derivatives are found in solvent extracts and kerogen pyrolysates of a Late Permian organic-rich marl from northern Italy. These organic compounds are distinguishable from biphenyl and its alkyl derivatives by high resolution GC–MS. Bulk geochemical (Rock-Eval) and transmitted/reflected light microscopic analyses indicate that the dominant source of organic matter in the Sediment is from partially decomposed land plant debris which has been transported into the marine depositional setting. A likely origin for the cyclic diaryl ether moieties is dehydrated and condensed polysaccharides. Possible sources for the polysaccharides are the organic constituents of land plants, microbes and fungi.