- Dr Michael Montenari FLS FGS DSc PhD Dipl-Geol
Earth Sciences and Geography
Keele University
William Smith Building
Newcastle (Staffs)
ST5 5BG
United Kingdom - (+44) 01782 733162
Michael Montenari
Keele University, Earth Sciences and Geography, Faculty Member
- My main research interests are coupled Geosphere/Biosphere processes. This includes the Sedimentology of extensional ... moreMy main research interests are coupled Geosphere/Biosphere processes. This includes the Sedimentology of extensional basins, the fragmentation of the Late Precambrian supercontinent Rodinia and associated processes, the sedimentological evolution of the Cantabrian Thrust Belt, Palaeoecology and Biogeography of selected fossil groups as facies indicators, the ultrastructural analysis of microfossils, fossil extremophiles and their relation to rock formation and deformation, Phanerozoic biogeochemical and isotope-biogeochemical signals as well as the geodynamic evolution of the Variscan Belt.edit
Research Interests:
We analysed 585 My old antitaxial fibrous calcite veins that formed at about 4-6 km depth in dark carbonaceous shales, found near Arkaroola, northern Flinders Ranges, South Australia [1]. The veins contain micron-sized biomorph... more
We analysed 585 My old antitaxial fibrous calcite veins that formed at about 4-6 km depth in dark carbonaceous shales, found near Arkaroola, northern Flinders Ranges, South Australia [1]. The veins contain micron-sized biomorph structures, such as coccus-and globular structures, ...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Abstract The structure of zircon, ZrSiO4 is modeled using interatomic potentials. The uranium end-member, coffinite (USiO4) and intermediate solid solutions of zircon and coffinite (UxZr1–xSiO4) are then modeled, allowing the prediction... more
Abstract The structure of zircon, ZrSiO4 is modeled using interatomic potentials. The uranium end-member, coffinite (USiO4) and intermediate solid solutions of zircon and coffinite (UxZr1–xSiO4) are then modeled, allowing the prediction of lattice parameters as a function of uranium concentration. Finally, possible structures resulting from the radioactive decay of uranium to lead in coffinite are considered.
Research Interests:
Research Interests:
Abstract During the early Silurian, widespread anoxic graptolitic black shales developed predominantly on the northern margin of Gondwana. These black shales are attracting a considerable amount of scientific interest, as it is nowadays... more
Abstract During the early Silurian, widespread anoxic graptolitic black shales developed predominantly on the northern margin of Gondwana. These black shales are attracting a considerable amount of scientific interest, as it is nowadays hypothesized that their genesis might be closely related to major changes within the paleogeographical configuration of continents, the oceanic circulation patterns, and also drastic global climatic perturbations. Furthermore, these black shale successions can be of highest economic significance, as some form the source rocks of the world's major oil reserves. For the present study, high-resolution whole rock geochemical data obtained from an early Silurian black shale source rock analogue (Formigoso Formation, Cantabrian Mountains, NW, Spain) are used to develop a chemostratigraphic framework and to reconstruct and further constrain the paleoenvironmental conditions that prevailed at the time of deposition. These chemostratigraphic interpretations and paleoenvironmental reconstructions are used, together with the results of previously published studies, to develop a detailed generic depositional model for the black shale successions of the Cantabrian Basin. This analogue model is compared and contrasted to previously proposed models. The new high-resolution chemostratigraphic data are combined with detailed biostratigraphic information from the published literature. The present study demonstrates that chemostratigraphic methods provide not only complementary but even vital information, especially where biostratigraphic data are absent or scarce, for larger scale intra- and interbasinal correlations.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Abstract Transcontinental correlation of European carbonate systems that developed during the onset of the Mesozoic breakup of Pangaea remains difficult due to pronounced lateral facies variations and in many cases facies-dependent fossil... more
Abstract Transcontinental correlation of European carbonate systems that developed during the onset of the Mesozoic breakup of Pangaea remains difficult due to pronounced lateral facies variations and in many cases facies-dependent fossil groups used for biostratigraphic dating and correlation. In addition, radiometric dating of ash layers associated with Middle Triassic carbonate successions in Europe is limited to certain areas and times of volcanic activity. Thus, Middle Triassic correlation schemes of the Tethyan and Peri-Tethyan realm—a highly dynamic area in terms of plate reorganization and related development of early Mesozoic epeiric seas—need further refinement using new correlation tools. Here, we highlight the Europe-wide occurrence of a silica-rich horizon at the Anisian–Ladinian boundary as a potential trans-European correlation horizon. Chert layers and nodules form in different depositional settings, under different conditions and within different facies, thus being well suited for interregional correlation. However, the processes leading to chert formation in Middle Triassic shallow-marine carbonate deposits are still under discussion and require further research in order to make this prominent feature a powerful correlation tool.
Research Interests:
"Abstract. - Within the Mid-European Variscan Belt, Heterocorallia have been described from the Rhenohercynian, the Saxothuringian and the Upper Austro-Alpine. A section from the Early Carboniferous of the Moldanubian Southern Vosges... more
"Abstract. - Within the Mid-European Variscan Belt, Heterocorallia have been described from the Rhenohercynian, the Saxothuringian and the Upper Austro-Alpine. A section from the Early Carboniferous of the Moldanubian Southern Vosges Mountains has yielded Heterocorallia, which are here described for the first time: Hexaphyllia sp. 1, Hexaphyllia sp. 2, Heterophyllia sp. and Heterophyllia aff. ornata M'Coy 1849. Their occurrence in calciclastic turbidites is an evidence for a Moldanubian Carbonate Platform. The fragile character of the heterocoral polypars in general might be an indication for low energy evironments within the platform. A comparison from Rhenohercynian, Saxothuringian and Moldanubian Heterocorallia results in good correspondence of the occuring taxa. Together with smaller benthic foraminifera it is possible to date the Heterocorallia bearing sediments from the Southern Vosges as Arundian (Visean). Kurzfassung. - Aus dem Mitteleuropaeischen Variszikum sind Heterokorallen bisher nur von Lokalitaeten beschrieben worden, die innerhalb der rhenoherzynischen Zone, der saxothuringischen Zone und dem Oberostalpin liegen. Ein Profil aus dem Unterkarbon der moldanubischen Suedvogesen hat Heterokorallen geliefert, die hier erstmals beschrieben werden: Hexaphyllia sp. 1, Hexaphyllia sp.2, Heterophyllia sp. und Heterophyllia aff. ornata M'Coy 1849. Sie treten dort in calciclastischen Turbiditen auf, die auf eine moldanubische Karbonatplattform hinweisen. Die Zerbrechlichkeit der Heterokorallen-Polupare laesst auf niedrig-energetische Bereiche innerhalb der Platform schliessen. Ein Vergleich der Heterokorallen-Formen aus den drei Zonen zeigt, dass keine grossen Unterschiede hinsichtlich der auftretenden Taxa bestehen. Zusammen mit benthischen Kleinforaminiferen lassen sich die Heterokorallen-fuehrenden Sedimente aus den Suedvogesen in das Arundian (Vise, Unterkarbon) einstufen. Resume. - Des Variscides de'Europe centrale, des Heterocorallia sont decrits jusqu'a present de localites situees dans les zones rhenohercynienne, saxothuringienne et du "Oberostalpine". Une section dans le Carbonifere inferieur des Vosges meridionales moldanubiennes a fourni des Heterocorallia qui sont decrits ici pour la premiere fois: Hexaphyllia sp. 1, Hexaphyllia sp. 2, Heterophyllia sp. et Heterophyllia aff. ornata M'Coy 1849. Ils sont issus de gisements calciclastiques turbiditiques qui indiquent une platforme carbonatee moldanubienne. La fragilite des polypares des Heterocorallia en general indique la presence de domaines de basse energie, Une comparraison entre des taxa Rhenohercyniens, Saxothuringienes et Moldanubiens des Heterocorallia ne revele pas des differences majeur. Il est possible, grace a de petites foraminiferes benthiques, de dater comme Arundien (Viseen, Carbonifere inferieur) les sediments a Heterocorallia des Vosges du sud. (c) 2002 E. Schweizerbart'sche Verlagsbuchhandlung Stuttgart."
Research Interests:
Research Interests:
Research Interests: Geology, Geochemistry, Geophysics, History of Science, Origins of Life, and 15 moreExperimental Design, Mass extinctions, Ediacaran, Proterozoic, Cambrian, Precambrian, Archaean, Climate Model, Origins of Cells, Origins of Eukaryotes, Origins of Metazoans, Foraminiferid Evolution, Evolution of Photosymbiosis, Complecxity and Evolution, and geosphere
Research Interests:
Research Interests: Geology and Paleontology
Research Interests:
Research Interests:
Silicified schwagerinids (superfamily Fusulinoidea v. Moeller 1878) from the Upper Carboniferous (Carnic Alps, Austria and Italy) were isolated from cemented carbonate rocks using hydrochloric acid. The shells show details of the wall... more
Silicified schwagerinids (superfamily Fusulinoidea v. Moeller 1878) from the Upper Carboniferous (Carnic Alps, Austria and Italy) were isolated from cemented carbonate rocks using hydrochloric acid. The shells show details of the wall texture and of internal structures in three dimensions which are illustrated with SEM pictures. Thin sections from hand specimens provided two-dimensional sections of the shell for comparison. The
Research Interests:
... Significant differences of the evolutionary acceleration of the proterozoic acritarchs (negative acceleration of vesicle diameters and simultaneous positive acceleration of diversity ... 178 MICHAELMONTENARI &... more
... Significant differences of the evolutionary acceleration of the proterozoic acritarchs (negative acceleration of vesicle diameters and simultaneous positive acceleration of diversity ... 178 MICHAELMONTENARI & URSULA LEPPIG ... 2. Morphological variability of acritarch processes. ...
Research Interests: Evolutionary Biology, Geology, Paleontology, Art, Ecology, and 4 moreProterozoic, Precambrian, Paleozoic, and Acritarch
und Literatur, Abhandlungen der Mathematisch-Naturwissenschaftlichen Klasse 9: 191-203. Seilacher, A. 1988. Why are nautiloid and ammonoid sutures so different? Neues lahrbuch for Geologie und Paliiontologie, Abhandlungen177(l): 41-69.... more
und Literatur, Abhandlungen der Mathematisch-Naturwissenschaftlichen Klasse 9: 191-203. Seilacher, A. 1988. Why are nautiloid and ammonoid sutures so different? Neues lahrbuch for Geologie und Paliiontologie, Abhandlungen177(l): 41-69. Tanabe, K., N. H. Landman, and R. H. Mapes. 1998. Muscle attachment scars in a Carboniferous goniatite. Paleontological Research 2(2): 130-136. Urlichs, M., and R. Mundlos. 1988. Zur Stratigraphie des Oberen Trochitenkalks (Oberer Muschelkalk, beranis) bei Crailsheim. In H. Hagdorn (editor), Neue Forschungen zur Erdgeschichte von Crailsheim. Sonderbiinde der Gesellschaft fiir Naturkunde in Wiirttemberg 1: 70-84. Vogel, K. P. 1959. Zwergwuchs bei Polyptychiten (Ammonoidea). Geologisches lahrbuch 76: 469-540. Wang, Y., and G. E. G. Westermann. 1993. Paleoecology of Triassic Ammonoids. Geobios 15: 373-392. Ward, P. D.1987. The Natural History of Nautilus. Boston: Allen & Unwin. Weitschat, W. 1986. Phosphatisierte Ammonoideen aus der Mittleren Trias von CentralSpitzbergen. Mitteilungen des Geologisch-Paliiontologischen Instituts der Universitiit Hamburg 61: 249-279. Weitschat, W., and K. Bandel. 1991. Organic components in phragmocones of boreal Triassic ammonoids: implications for ammonoid biology. Paliiontologische ZeitschriJt 65: 269-303. Weitschat, W., and K. Bandel. 1992. Formation and function of suspended organic cameral sheets in Triassic ammonoids: reply. Paliiontologische ZeitschriJt 66: 443-444. Wenger, R. 1957. Die Ceratiten der gennanischen Trias. Palaeontographica A 108: 57-129. Westennann, G. E. G. 1992. Fonnation and function of suspended organic cameral sheets in Triassic ammonoids discussion. Paliiontologische ZeitschriJt 66: 437-441. Zaborski, P. M. P. 1986. Internal mould markings in a Cretaceous ammonite from Nigeria. Palaeontology 29: 725-738. Chapter 10 Soft-tissue Attachment of Middle Triassic Ceratitida from Germany
Research Interests:
Marine red beds (MRBs), also known as oceanic red beds (ORBs), are reddish colored sediments deposited within the marine realm that have been stained during deposition and/or early diagenesis because of changes in the ocean water... more
Marine red beds (MRBs), also known as oceanic red beds (ORBs), are reddish colored sediments deposited within the marine realm that have been stained during deposition and/or early diagenesis because of changes in the ocean water chemistry in response to paleoceanographic and paleoclimatological factors. Although common throughout the Phanerozoic, marine red beds have mostly been investigated in Upper Cretaceous successions as CORBs (Cretaceous Oceanic Red Beds)-their occurrence and paleoceanographic context within the Paleozoic has yet to be studied in detail. Here we describe and interpret the high-resolution litho-and chemofacies of Early Carboniferous (Late Viséan) marine red beds from the northern coast of Menorca (Balearic Islands, Spain) that mark a rapid transition from siliceous radiolarian chert deposition to reworked carbonate debrites followed by typical European Culm facies. The succession was deposited within a strait-like narrow basin that formed part of the Alboran-Kabylian-Peloritan-Calabrian terrane in the Western Paleotethys Ocean prior to the onset of the Variscan Orogeny. The marine red bed geochemistry is described in terms of three geochemical endmembers Al-MRBs (clayey), Ca-MRBs (calcareous) and Si-MRBs (siliceous) by using XRF-derived Al 2 O 3 , CaO, and SiO 2 concentrations. This study finds that Viséan marine red beds from Menorca are predominantly Al-MRBs with subordinate Ca-MRBs. Furthermore, we compare the bulk rock geochemistry of the Viséan marine red beds of this study with the geochemical data of Paleozoic, Mesozoic and Cenozoic marine red beds available in the existing literature (Cambrian, Silurian, Jurassic, Cretaceous, Paleogene and recent Pacific Ocean red clays) to highlight the significance of marine red bed occurrences in relation to (paleo-)bioproductivity fluctuations, deepwater oxygenation and oceanic redox transitions. This study finds that Phanerozoic marine red beds are dominantly Al-MRBs and Ca-MRBs, whilst Si-MRBs are less common. The Early Carboniferous marine red beds of the present study were formed in a distal, deeper-marine environment under oxic-suboxic, oligotrophic conditions. A lack of any significant Fe 2 O 3 T enrichment points towards a more complex diagenetic process for the origin of the red color imparted in Phanerozoic MRBs.
Research Interests:
Research Interests: Geology and Paleontology
Research Interests: Ecology and Diagenesis
Research Interests:
Marine red beds (MRBs), also known as oceanic red beds (ORBs), are reddish colored sediments deposited within the marine realm that have been stained during deposition and/or early diagenesis because of changes in the ocean water... more
Marine red beds (MRBs), also known as oceanic red beds (ORBs), are reddish colored sediments deposited within the marine realm that have been stained during deposition and/or early diagenesis because of changes in the ocean water chemistry in response to paleoceanographic and paleoclimatological factors. Although common throughout the Phanerozoic, marine red beds have mostly been investigated in Upper Cretaceous successions as CORBs (Cretaceous Oceanic Red Beds)-their occurrence and paleoceanographic context within the Paleozoic has yet to be studied in detail. Here we describe and interpret the high-resolution litho-and chemofacies of Early Carboniferous (Late Viséan) marine red beds from the northern coast of Menorca (Balearic Islands, Spain) that mark a rapid transition from siliceous radiolarian chert deposition to reworked carbonate debrites followed by typical European Culm facies. The succession was deposited within a strait-like narrow basin that formed part of the Alboran-Kabylian-Peloritan-Calabrian terrane in the Western Paleotethys Ocean prior to the onset of the Variscan Orogeny. The marine red bed geochemistry is described in terms of three geochemical endmembers Al-MRBs (clayey), Ca-MRBs (calcareous) and Si-MRBs (siliceous) by using XRF-derived Al 2 O 3 , CaO, and SiO 2 concentrations. This study finds that Viséan marine red beds from Menorca are predominantly Al-MRBs with subordinate Ca-MRBs. Furthermore, we compare the bulk rock geochemistry of the Viséan marine red beds of this study with the geochemical data of Paleozoic, Mesozoic and Cenozoic marine red beds available in the existing literature (Cambrian, Silurian, Jurassic, Cretaceous, Paleogene and recent Pacific Ocean red clays) to highlight the significance of marine red bed occurrences in relation to (paleo-)bioproductivity fluctuations, deepwater oxygenation and oceanic redox transitions. This study finds that Phanerozoic marine red beds are dominantly Al-MRBs and Ca-MRBs, whilst Si-MRBs are less common. The Early Carboniferous marine red beds of the present study were formed in a distal, deeper-marine environment under oxic-suboxic, oligotrophic conditions. A lack of any significant Fe 2 O 3 T enrichment points towards a more complex diagenetic process for the origin of the red color imparted in Phanerozoic MRBs.
Research Interests:
The Southern Ocean occupies 14% of the Earth’s surface and plays a fundamental role in the global carbon cycle and climate. It provides a direct connection to the deep ocean carbon reservoir through biogeochemical processes that include... more
The Southern Ocean occupies 14% of the Earth’s surface and plays a fundamental role in the global carbon cycle and climate. It
provides a direct connection to the deep ocean carbon reservoir through biogeochemical processes that include surface primary
productivity, remineralization at depth and the upwelling of carbon-rich water masses. However, the role of these different processes
in modulating past and future air–sea carbon flux remains poorly understood. A key period in this regard is the Antarctic
Cold Reversal (ACR, 14.6–12.7 kyr bp), when mid- to high-latitude Southern Hemisphere cooling coincided with a sustained
plateau in the global deglacial increase in atmospheric CO2. Here we reconstruct high-latitude Southern Ocean surface productivity
from marine-derived aerosols captured in a highly resolved horizontal ice core. Our multiproxy reconstruction reveals a
sustained signal of enhanced marine productivity across the ACR. Transient climate modelling indicates this period coincided
with maximum seasonal variability in sea-ice extent, implying that sea-ice biological feedbacks enhanced CO2 sequestration
and created a substantial regional marine carbon sink, which contributed to the plateau in CO2 during the ACR. Our results
highlight the role Antarctic sea ice plays in controlling global CO2, and demonstrate the need to incorporate such feedbacks into
climate–carbon models.
provides a direct connection to the deep ocean carbon reservoir through biogeochemical processes that include surface primary
productivity, remineralization at depth and the upwelling of carbon-rich water masses. However, the role of these different processes
in modulating past and future air–sea carbon flux remains poorly understood. A key period in this regard is the Antarctic
Cold Reversal (ACR, 14.6–12.7 kyr bp), when mid- to high-latitude Southern Hemisphere cooling coincided with a sustained
plateau in the global deglacial increase in atmospheric CO2. Here we reconstruct high-latitude Southern Ocean surface productivity
from marine-derived aerosols captured in a highly resolved horizontal ice core. Our multiproxy reconstruction reveals a
sustained signal of enhanced marine productivity across the ACR. Transient climate modelling indicates this period coincided
with maximum seasonal variability in sea-ice extent, implying that sea-ice biological feedbacks enhanced CO2 sequestration
and created a substantial regional marine carbon sink, which contributed to the plateau in CO2 during the ACR. Our results
highlight the role Antarctic sea ice plays in controlling global CO2, and demonstrate the need to incorporate such feedbacks into
climate–carbon models.
The Protocanites Beds of the Black Forest Massif (Germany) form an important lithostratigraphic key bed, as the index fossils contained in this formation enable correlation within large areas of the internal zone of the central Variscan... more
The Protocanites Beds of the Black Forest Massif (Germany) form an important lithostratigraphic key bed, as the index fossils contained in this formation enable correlation within large areas of the internal zone of the central Variscan Belt of Europe. Furthermore, the formation provides significant information on the geodynamic evolution of the Moldanubian Zone. The stratigraphic age of the formation has been a subject of controversy in the past; a Devonian to Viséan age has been proposed. To determine the age of the Protocanites Beds, two ammonoid specimens from the Protocanites Beds of Schönau are re-described here. They belong to Becanites abnobensis and Pericylcus princeps and fix the stratigraphic position of the Protocanites Beds to the early Late Tournaisian.
Research Interests:
Research Interests:
Transcontinental correlation of European carbonate systems that developed during the onset of the Mesozoic breakup of Pangaea remains difficult due to pronounced lateral facies variations and in many cases facies-dependent fossil groups... more
Transcontinental correlation of European carbonate systems that developed during the
onset of the Mesozoic breakup of Pangaea remains difficult due to pronounced lateral
facies variations and in many cases facies-dependent fossil groups used for biostratigraphic dating and correlation. In addition, radiometric dating of ash layers associated with Middle Triassic carbonate successions in Europe is limited to certain areas and times of volcanic activity. Thus, Middle Triassic correlation schemes of the Tethyan and Peri-Tethyan realm—a highly dynamic area in terms of plate reorganization and related development of early Mesozoic epeiric seas—need further refinement using
new correlation tools. Here, we highlight the Europe-wide occurrence of a silica-rich horizon at the Anisian–Ladinian boundary as a potential trans-European correlation
horizon. Chert layers and nodules form in different depositional settings, under different
conditions and within different facies, thus being well suited for interregional correlation.
However, the processes leading to chert formation in Middle Triassic shallowmarine
carbonate deposits are still under discussion and require further research in
order to make this prominent feature a powerful correlation tool.
onset of the Mesozoic breakup of Pangaea remains difficult due to pronounced lateral
facies variations and in many cases facies-dependent fossil groups used for biostratigraphic dating and correlation. In addition, radiometric dating of ash layers associated with Middle Triassic carbonate successions in Europe is limited to certain areas and times of volcanic activity. Thus, Middle Triassic correlation schemes of the Tethyan and Peri-Tethyan realm—a highly dynamic area in terms of plate reorganization and related development of early Mesozoic epeiric seas—need further refinement using
new correlation tools. Here, we highlight the Europe-wide occurrence of a silica-rich horizon at the Anisian–Ladinian boundary as a potential trans-European correlation
horizon. Chert layers and nodules form in different depositional settings, under different
conditions and within different facies, thus being well suited for interregional correlation.
However, the processes leading to chert formation in Middle Triassic shallowmarine
carbonate deposits are still under discussion and require further research in
order to make this prominent feature a powerful correlation tool.
Research Interests:
Abstract Transcontinental correlation of European carbonate systems that developed during the onset of the Mesozoic breakup of Pangaea remains difficult due to pronounced lateral facies variations and in many cases facies-dependent fossil... more
Abstract Transcontinental correlation of European carbonate systems that developed during the onset of the Mesozoic breakup of Pangaea remains difficult due to pronounced lateral facies variations and in many cases facies-dependent fossil groups used for biostratigraphic dating and correlation. In addition, radiometric dating of ash layers associated with Middle Triassic carbonate successions in Europe is limited to certain areas and times of volcanic activity. Thus, Middle Triassic correlation schemes of the Tethyan and Peri-Tethyan realm—a highly dynamic area in terms of plate reorganization and related development of early Mesozoic epeiric seas—need further refinement using new correlation tools. Here, we highlight the Europe-wide occurrence of a silica-rich horizon at the Anisian–Ladinian boundary as a potential trans-European correlation horizon. Chert layers and nodules form in different depositional settings, under different conditions and within different facies, thus being well suited for interregional correlation. However, the processes leading to chert formation in Middle Triassic shallow-marine carbonate deposits are still under discussion and require further research in order to make this prominent feature a powerful correlation tool.
Research Interests:
Silicified schwagerinids (superfamily Fusulinoidea v. Moeller 1878) from the Upper Carboniferous (Carnic Alps, Austria and Italy) were isolated from cemented carbonate rocks using hydrochloric acid. The shells show details of the wall... more
Silicified schwagerinids (superfamily Fusulinoidea v. Moeller 1878) from the Upper Carboniferous (Carnic Alps, Austria and Italy) were isolated from cemented carbonate rocks using hydrochloric acid. The shells show details of the wall texture and of internal structures in three dimensions which are illustrated with SEM pictures. Thin sections from hand specimens provided twodimensional sections of the shell for comparison. The functional significance of fusulinoidean internal structures is discussed and compared with verbeekinoideans and alveolinids. Particular attention is paid on the disposition of the different openings within the shell and from the chamber lumen to the outside which reflects the direction of protoplasmic flow. Based on the knowledge of the nature of protoplasm ultrastructure in Recent foraminifera and its biological significance we draw some conclusions about the nature of protoplasm in fusulinoideans and its change within the Permian verbeekinoideans.
Research Interests:
In recent years, unconventional hydrocarbon reservoirs (UHRs), specifically shale gas plays, have become a vast source of economically viable hydrocarbons, in response to better drilling and stimulation techniques. To further improve... more
In recent years, unconventional hydrocarbon reservoirs (UHRs), specifically shale gas plays, have become a vast source of economically viable hydrocarbons, in response to better drilling and stimulation techniques. To further improve recovery, more detailed pore network modeling needs to be conducted by means of detailed pore network
characterizations, based upon predefined pore size and pore type classification schemes. Through the quantification of the nano/microporous properties of the pore network, a better understanding on how hydrocarbon storage and migration phenomena operate within UHRs and how well they might respond to stimulation can be developed.
Kasimovian-Gzhelian (Late Carboniferous) lacustrine sediments from the Upper Pastora Formation of the Ciñera-Matallana coalfield, NW Spain, were investigated to identify the potential for shale gas, by conducting a detailed pore network analysis using SEM-based porosity data, alongside traditional methods of formation evaluation. Here we show that the Upper Pastora Formation demonstrates shale gas potential and that the nanoporous network is a complex multifaceted and multi-scaled system composed of various pore types and sizes, each with specific dynamic properties and varying contributions toward total porosity. The present contribution provides a full pore network characterization and quantification, based on pore type and size, followed by a quantification
of the porosity percentage held within each pore type and size. This work will provide an insight into the need for pore network characterizations alongside pore property quantifications with regard to computational fluid flow models and as such the need to carry out this work in conjunction with more traditional methods of shale gas exploration.
characterizations, based upon predefined pore size and pore type classification schemes. Through the quantification of the nano/microporous properties of the pore network, a better understanding on how hydrocarbon storage and migration phenomena operate within UHRs and how well they might respond to stimulation can be developed.
Kasimovian-Gzhelian (Late Carboniferous) lacustrine sediments from the Upper Pastora Formation of the Ciñera-Matallana coalfield, NW Spain, were investigated to identify the potential for shale gas, by conducting a detailed pore network analysis using SEM-based porosity data, alongside traditional methods of formation evaluation. Here we show that the Upper Pastora Formation demonstrates shale gas potential and that the nanoporous network is a complex multifaceted and multi-scaled system composed of various pore types and sizes, each with specific dynamic properties and varying contributions toward total porosity. The present contribution provides a full pore network characterization and quantification, based on pore type and size, followed by a quantification
of the porosity percentage held within each pore type and size. This work will provide an insight into the need for pore network characterizations alongside pore property quantifications with regard to computational fluid flow models and as such the need to carry out this work in conjunction with more traditional methods of shale gas exploration.
Research Interests:
Shallow-water carbonates from the Lower Permian of Sonora, northwest Mexico, have yielded small organic-walled microfossils that show several features characteristic of dinoflagellates. The oldest unequivocal dinoflagellate fossils,... more
Shallow-water carbonates from the Lower Permian of Sonora, northwest Mexico, have yielded small organic-walled microfossils that show several features characteristic of dinoflagellates. The oldest unequivocal dinoflagellate fossils, however, presently known come from the Middle Triassic. Earlier reports of microfossils with possible dinoflagellate affinity from the Paleozoic and Neoproterozoic, together with dinoflagellate-specific biomarkers found in Early Cambrian rocks and molecular phylogenetic analyses, suggest the presence of an intermediate stage of evolution, or protodinoflagellate group in pre-Mesozoic times.
Research Interests:
Determining the feedbacks that modulate Southern Ocean carbon dynamics is key to understanding past and future climate. The global pause in rising atmospheric CO2 during the period of mid- to high-latitude southern surface cooling known... more
Determining the feedbacks that modulate Southern Ocean carbon dynamics is key to understanding past and future climate. The global pause in rising atmospheric CO2 during the period of mid- to high-latitude southern surface cooling known as the Antarctic Cold Reversal (ACR, 14,700-12,700 years ago) provides an opportunity to disentangle competing influences. We present highly-resolved and precisely-aligned ice and marine reconstructions that capture a previously unrecognized increase in microbial diversity and ocean primary productivity during the ACR. Transient climate modeling across the last glacial suggests this period corresponds to a maximum seasonal difference in sea-ice extent. Our results indicate that this increased seasonal sea-ice variability drove changes in high-latitude light, temperature and nutrient availability, turning the southern seasonal sea-ice zone into a globally significant carbon sink.
Research Interests:
During the early Silurian, widespread anoxic graptolitic black shales developed predominantly on the northern margin of Gondwana. These black shales are attracting a considerable amount of scientific interest, as it is nowadays... more
During the early Silurian, widespread anoxic graptolitic black shales developed predominantly on the northern margin of Gondwana. These black shales are attracting a considerable amount of scientific interest, as it is nowadays hypothesized that their genesis might be closely related to major changes within the paleogeographical configuration of continents, the oceanic circulation patterns, and also drastic global climatic perturbations. Furthermore, these black shale successions can be of highest economic significance, as some form the source rocks of the world’s major oil reserves. For the present study, high-resolution whole rock geochemical data obtained from an early Silurian black shale source rock analogue (Formigoso Formation, Cantabrian Mountains, NW, Spain) are used to develop a chemostratigraphic framework and to reconstruct and further constrain the paleoenvironmental conditions that prevailed at
the time of deposition. These chemostratigraphic interpretations and paleoenvironmental reconstructions are used, together with the results of previously published studies, to develop a detailed generic depositional model for the black shale successions of the Cantabrian Basin. This analogue model is compared and contrasted to previously proposed models. The new high-resolution chemostratigraphic data are combined with detailed biostratigraphic information from the published literature. The present study demonstrates that chemostratigraphic methods provide not only complementary but even vital information, especially where biostratigraphic data are absent or scarce, for larger scale intra- and interbasinal correlations.
the time of deposition. These chemostratigraphic interpretations and paleoenvironmental reconstructions are used, together with the results of previously published studies, to develop a detailed generic depositional model for the black shale successions of the Cantabrian Basin. This analogue model is compared and contrasted to previously proposed models. The new high-resolution chemostratigraphic data are combined with detailed biostratigraphic information from the published literature. The present study demonstrates that chemostratigraphic methods provide not only complementary but even vital information, especially where biostratigraphic data are absent or scarce, for larger scale intra- and interbasinal correlations.
Research Interests:
Abstract During the early Silurian, widespread anoxic graptolitic black shales developed predominantly on the northern margin of Gondwana. These black shales are attracting a considerable amount of scientific interest, as it is nowadays... more
Abstract During the early Silurian, widespread anoxic graptolitic black shales developed predominantly on the northern margin of Gondwana. These black shales are attracting a considerable amount of scientific interest, as it is nowadays hypothesized that their genesis might be closely related to major changes within the paleogeographical configuration of continents, the oceanic circulation patterns, and also drastic global climatic perturbations. Furthermore, these black shale successions can be of highest economic significance, as some form the source rocks of the world's major oil reserves. For the present study, high-resolution whole rock geochemical data obtained from an early Silurian black shale source rock analogue (Formigoso Formation, Cantabrian Mountains, NW, Spain) are used to develop a chemostratigraphic framework and to reconstruct and further constrain the paleoenvironmental conditions that prevailed at the time of deposition. These chemostratigraphic interpretations and paleoenvironmental reconstructions are used, together with the results of previously published studies, to develop a detailed generic depositional model for the black shale successions of the Cantabrian Basin. This analogue model is compared and contrasted to previously proposed models. The new high-resolution chemostratigraphic data are combined with detailed biostratigraphic information from the published literature. The present study demonstrates that chemostratigraphic methods provide not only complementary but even vital information, especially where biostratigraphic data are absent or scarce, for larger scale intra- and interbasinal correlations.
Research Interests:
Research Interests:
Abstract The structure of zircon, ZrSiO4 is modeled using interatomic potentials. The uranium end-member, coffinite (USiO4) and intermediate solid solutions of zircon and coffinite (UxZr1–xSiO4) are then modeled, allowing the prediction... more
Abstract The structure of zircon, ZrSiO4 is modeled using interatomic potentials. The uranium end-member, coffinite (USiO4) and intermediate solid solutions of zircon and coffinite (UxZr1–xSiO4) are then modeled, allowing the prediction of lattice parameters as a function of uranium concentration. Finally, possible structures resulting from the radioactive decay of uranium to lead in coffinite are considered.
Research Interests:
"Exceptionally preserved specimens of the genera Myophoria, Neoschizodus and Trigonodus (Bivalvia, Palaeoheterodonta, Trigonioida) from carbonate sediments of the Muschelkalk (Anisian, Ladinian) contain phosphatized softtissues. This... more
"Exceptionally preserved specimens of the genera
Myophoria, Neoschizodus and Trigonodus (Bivalvia, Palaeoheterodonta,
Trigonioida) from carbonate sediments of the
Muschelkalk (Anisian, Ladinian) contain phosphatized softtissues.
This is the oldest record of soft-tissue preservation in
bivalves and the first from the German Muschelkalk. The
phosphatized remains are here interpreted as relics of the
originally chitinous gill supports, the gill axis, the labial palps
(?), the adductor muscles, the pedal retractor muscles, the
mantle margin including the radial mantle musculature, and
the ‘siphons’. According to microprobe analysis, the mineral
replacing the soft-tissue is mainly apatite and, more rarely,
francolite. Additionally, quartz filled voids within the gill
supports, and in one sample it occurs in minute crystals in
the phosphatized remains of the adductor muscle of Neoschizodus.
Myophoria, Neoschizodus and Trigonodus were softbottom
dwellers and five of the specimens were discovered
in life position. This is indicated by geopetal structures in
three specimens."
Myophoria, Neoschizodus and Trigonodus (Bivalvia, Palaeoheterodonta,
Trigonioida) from carbonate sediments of the
Muschelkalk (Anisian, Ladinian) contain phosphatized softtissues.
This is the oldest record of soft-tissue preservation in
bivalves and the first from the German Muschelkalk. The
phosphatized remains are here interpreted as relics of the
originally chitinous gill supports, the gill axis, the labial palps
(?), the adductor muscles, the pedal retractor muscles, the
mantle margin including the radial mantle musculature, and
the ‘siphons’. According to microprobe analysis, the mineral
replacing the soft-tissue is mainly apatite and, more rarely,
francolite. Additionally, quartz filled voids within the gill
supports, and in one sample it occurs in minute crystals in
the phosphatized remains of the adductor muscle of Neoschizodus.
Myophoria, Neoschizodus and Trigonodus were softbottom
dwellers and five of the specimens were discovered
in life position. This is indicated by geopetal structures in
three specimens."
Research Interests:
ABSTRACT
Research Interests:
Research Interests:
We analysed 585 My old antitaxial fibrous calcite veins that formed at about 4-6 km depth in dark carbonaceous shales, found near Arkaroola, northern Flinders Ranges, South Australia [1]. The veins contain micron-sized biomorph... more
We analysed 585 My old antitaxial fibrous calcite veins that formed at about 4-6 km depth in dark carbonaceous shales, found near Arkaroola, northern Flinders Ranges, South Australia [1]. The veins contain micron-sized biomorph structures, such as coccus-and globular structures, ...
Research Interests:
The Neoproterozoic was characterized by an extreme glaciation, but until now there has been no consensus as to whether it was a complete glaciation (snowball Earth) or a less severe glaciation (slushball Earth). We performed sensitivity... more
The Neoproterozoic was characterized by an extreme glaciation, but until now there has been no consensus as to whether it was a complete glaciation (snowball Earth) or a less severe glaciation (slushball Earth). We performed sensitivity experiments with an Earth model of intermediate complexity for this period of dramatic global cooling. Our simulations focus on the climate response on a cool versus a cold ocean, on a desert versus a glacier land surface, and on a lower versus a higher CO2 concentration. All Neoproterozoic model experiments represent much colder conditions than today and widespread glaciation. In case of an initial forcing representing a snowball Earth, the model maintains its complete glaciation, and temperatures are as low as –45 °C in equatorial latitudes. At the poles, the snowball experiments demonstrate annual average temperatures of <–70 °C. If the initial model forcing is more moderate (slush-ball Earth), polar temperatures are <–50 °C, but temperatures in low latitudes stay well above the freezing point of water, and therefore ice-free ocean areas remain. Based on our simulations, we are able to observe that global climate reacts less sensitively to reductions of atmospheric CO2 during times with increased glaciations. Our results suggest that the development of glaciers on land contributes significantly to intense ice coverage of the oceans. Because simulations initialized without complete ice cover do not reach the global glaciation condition, we conclude that our simulations support the rather moderate scenario of a slushball Earth than the extreme snowball Earth hypothesis. The experimental design and the model might, however, limit the interpretation of our results.
Keywords: Neoproterozoic • snowball Earth • climate modeling • climate modeling sensitivity experiment
Keywords: Neoproterozoic • snowball Earth • climate modeling • climate modeling sensitivity experiment