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Roger Trend - One of the best experts on this subject based on the ideXlab platform.
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deep Time framework a preliminary study of u k primary teachers conceptions of Geological Time and perceptions of geoscience
Journal of Research in Science Teaching, 2001Co-Authors: Roger TrendAbstract:As part of a continuing research program on the understanding of Geological Time (deep Time) across society, a total of 51 in-service teachers of 7- to 11-year-old children was studied in relation to their orientations toward geoscience phenomena in general and deep Time in particular. The first purpose of the research was to identify the nature of idiosyncratic conceptions of deep Time: a cognitive deep Time framework of pivotal geo-events. The second was to propose a curricular Deep Time Framework that may form the basis for constructivist approaches to in-service and pre-service teacher training which places deep Time center stage. Three research questions were posed, addressing: (1) perceptions of geoscience phenomena and teachers' actual encounters with these in the classroom; (2) conceptions of deep Time; and (3) approaches to teaching two curriculum areas (history and geology) which involve the interpretation of material evidence to reconstruct the past. Results enable the selection of 20 geoscience phenomena to be located in relation to teachers' interests and classroom encounters, those of high interest and high encounters being proposed as pivotal areas for further attention in teacher training. Results also reveal that in-service teachers conceive events in the Geological past (geo-events) as having occurred in three distinct clusters: extremely ancient; moderately ancient; and less ancient. Within each category there is a strong lack of consensus on Time-of-occurrence. Results suggest that primary teachers exhibit greater imagination in their teaching of history compared with geology and that aspects of deep Time and past environments are not perceived as being of any great significance in the interpretation of Geological specimens. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 191–221, 2001
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An Investigation into the Understanding of Geological Time among 17-year-old Students, with Implications for the Subject Matter Knowledge of Future Teachers
International Research in Geographical and Environmental Education, 2001Co-Authors: Roger TrendAbstract:Conceptions of Geological Time among 17-year-old students are examined in order to explore the subject matter knowledge of beginning teachers from the pivotal educational context of GCE Advanced Level. The concept of Time has received much attention over the centuries from many perspectives, but the Geological perspective is poorly represented in popular literature: historical and scientific/theoretical perspectives dominate. The 'everyday' influences on beginning teachers' understanding of Geological Time are important because of their absence from formal school curricula. Perceptions of 136 17-year-old students were investigated using two instruments. One study identified those major geo-events in their collective consciousness. High-profile geo-events include dinosaur appearance and extinction, continental fragmentation, emergence of plants, human evolution and Ice Age/s. Misconceptions relating to Big Bang and related phenomena were identified. The second study probed students' understanding across 24...
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Conceptions of Geological Time among primary teacher trainees, with reference to their engagement with geoscience, history, and science
International Journal of Science Education, 2000Co-Authors: Roger TrendAbstract:People's grasp of Geological Time is under-researched, despite attention being devoted to the philosophy of Time. Research carried out with 179 pre-service primary teachers suggests they perceive events in Earth's Geological past as falling into three distinct clusters: extremely ancient, less ancient and Geologically recent. Respondents' grasp of relative Time is more secure than their grasp of absolute Time and instruments which address absolute Time generate less conclusive evidence than do those requiring simple sequencing. Trainee teachers vary in their geoscience interests and classroom experiences and are more comfortable and imaginative with their teaching of history than with their geology, despite the parallels. In order to render more secure people's learning of geoscience concepts and processes, a deep Time framework is needed for each learner, individualized to accommodate learner characteristics and local geoscience features.
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an investigation into understanding of Geological Time among 10 and 11 year old children
International Journal of Science Education, 1998Co-Authors: Roger TrendAbstract:This research focused on the understanding of Geological Time among UK children aged 10 and 11 years. The empirical study, in two stages, involved a total of 189 children in activities designed to reveal knowledge and understanding of Geological Time. The preliminary study with 12 children was designed to identify the most powerful and appropriate techniques to use in the Main Study. It also resulted in some findings concerned with the place of deep Time in children's conceptualization of Earth events. The Main Study, with 177 children, involved the sequencing of Geological events in three separate but almost identical tasks. Results indicate that children of this age have a general awareness of major events such as the Ice Age and moving continents, but that a clear chronology is almost entirely lacking. Children conceive of events as falling into two distinct Time zones: the ‘extremely ancient’ and the ‘less ancient’.
Karel Martínek - One of the best experts on this subject based on the ideXlab platform.
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a review of the middle late pennsylvanian west european regional substages and floral biozones and their correlation to the Geological Time scale based on new u pb ages
Earth-Science Reviews, 2016Co-Authors: Stanislav Opluštil, Mark D. Schmitz, Christopher J. Cleal, Karel MartínekAbstract:Abstract Lower Moscovian (Duckmantian) to lower Asselian ash beds in the continental basins of the central and western Czech Republic have yielded 15 new high-precision U–Pb single crystal zircon CA-ID-TIMS ages. These are used to improve the calibration of the West European regional terrestrial stages and their correlation to the Geological Time Scale. They also allow an improved correlation between the macrofloral biozones that are used for biostratigraphy in the European Pennsylvanian coalfields, the marine biozones on which the global Geological Time Scale was partly established, and the fresh-water and terrestrial faunal biozones. Most of the floral biozones have proved to be essentially isochronous, although the ranges of some individual but stratigraphically important taxa may differ between basins.
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A review of the Middle–Late Pennsylvanian west European regional substages and floral biozones, and their correlation to the Geological Time Scale based on new U–Pb ages
Earth-Science Reviews, 2016Co-Authors: Stanislav Opluštil, Mark D. Schmitz, Christopher J. Cleal, Karel MartínekAbstract:Abstract Lower Moscovian (Duckmantian) to lower Asselian ash beds in the continental basins of the central and western Czech Republic have yielded 15 new high-precision U–Pb single crystal zircon CA-ID-TIMS ages. These are used to improve the calibration of the West European regional terrestrial stages and their correlation to the Geological Time Scale. They also allow an improved correlation between the macrofloral biozones that are used for biostratigraphy in the European Pennsylvanian coalfields, the marine biozones on which the global Geological Time Scale was partly established, and the fresh-water and terrestrial faunal biozones. Most of the floral biozones have proved to be essentially isochronous, although the ranges of some individual but stratigraphically important taxa may differ between basins.
David L. Leach - One of the best experts on this subject based on the ideXlab platform.
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Mississippi Valley-type lead–zinc deposits through Geological Time: implications from recent age-dating research
Mineralium Deposita, 2001Co-Authors: David L. Leach, Dwight Bradley, Michael T. Lewchuk, David T. Symons, Ghislain De Marsily, Joyce BrannonAbstract:Remarkable advances in age dating Mississippi Valley-type (MVT) lead–zinc deposits provide a new opportunity to understand how and where these deposits form in the Earth's crust. These dates are summarized and examined in a framework of global tectonics, paleogeography, fluid migration, and paleoclimate. Nineteen districts have been dated by paleomagnetic and/or radiometric methods. Of the districts that have both paleomagnetic and radiometric dates, only the Pine Point and East Tennessee districts have significant disagreements. This broad agreement between paleomagnetic and radiometric dates provides added confidence in the dating techniques used. The new dates confirm the direct connection between the genesis of MVT lead–zinc ores with global-scale tectonic events. The dates show that MVT deposits formed mainly during large contractional tectonic events at restricted Times in the history of the Earth. Only the deposits in the Lennard Shelf of Australia and Nanisivik in Canada have dates that correspond to extensional tectonic events. The most important period for MVT genesis was the Devonian to Permian Time, which corresponds to a series of intense tectonic events during the assimilation of Pangea. The second most important period for MVT genesis was Cretaceous to Tertiary Time when microplate assimilation affected the western margin of North America and Africa–Eurasia. There is a notable paucity of MVT lead–zinc ore formation following the breakup of Rodinia and Pangea. Of the five MVT deposits hosted in Proterozoic rocks, only the Nanisivik deposit has been dated as Proterozoic. The contrast in abundance between SEDEX and MVT lead–zinc deposits in the Proterozoic questions the frequently suggested notion that the two types of ores share similar genetic paths. The ages of MVT deposits, when viewed with respect to the orogenic cycle in the adjacent orogen suggest that no single hydrologic model can be universally applied to the migration of the ore fluids. However, topographically driven models best explain most MVT districts. The migration of MVT ore fluids is not a natural consequence of basin evolution; rather, MVT districts formed mainly where platform carbonates had some hydrological connection to orogenic belts. There may be a connection between paleoclimate and the formation of some MVT deposits. This possible relationship is suggested by the dominance of evaporated seawater in fluid inclusions in MVT ores, by hydrological considerations that include the need for multiple-basin volumes of ore fluid to form most MVT districts, and the need for adequate precipitation to provide sufficient topographic head for topographically-driven fluid migration. Paleoclimatic conditions that lead to formation of evaporite conditions but yet have adequate precipitation to form large hydrological systems are most commonly present in low latitudes. For the MVT deposits and districts that have been dated, more than 75% of the combined metal produced are from deposits that have dates that correspond to assembly of Pangea in Devonian through Permian Time. The exceptional endowment of Pangea and especially, North America with MVT lead–zinc deposits may be explained by the following: (1) Laurentia, which formed the core of North America, stayed in low latitudes during the Paleozoic, which allowed the development of vast carbonate platforms; (2) intense orogenic activity during the assembly of Pangea created ground preparation for many MVT districts through far-field deformation of the craton; (3) uplifted orogenic belts along Pangean suture zones established large-scale migration of basin fluids; and (4) the location of Pangea in low latitudes with paleoclimates with high evaporation rates led to the formation of brines by the evaporation of seawater and infiltration of these brines into deep basin aquifers during Pangean orogenic events.
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mississippi valley type lead zinc deposits through Geological Time implications from recent age dating research
Mineralium Deposita, 2001Co-Authors: David L. Leach, Michael T. Lewchuk, David T. Symons, Ghislain De Marsily, Dwight C Bradley, Joyce C BrannonAbstract:Remarkable advances in age dating Mississippi Valley-type (MVT) lead–zinc deposits provide a new opportunity to understand how and where these deposits form in the Earth's crust. These dates are summarized and examined in a framework of global tectonics, paleogeography, fluid migration, and paleoclimate. Nineteen districts have been dated by paleomagnetic and/or radiometric methods. Of the districts that have both paleomagnetic and radiometric dates, only the Pine Point and East Tennessee districts have significant disagreements. This broad agreement between paleomagnetic and radiometric dates provides added confidence in the dating techniques used. The new dates confirm the direct connection between the genesis of MVT lead–zinc ores with global-scale tectonic events. The dates show that MVT deposits formed mainly during large contractional tectonic events at restricted Times in the history of the Earth. Only the deposits in the Lennard Shelf of Australia and Nanisivik in Canada have dates that correspond to extensional tectonic events. The most important period for MVT genesis was the Devonian to Permian Time, which corresponds to a series of intense tectonic events during the assimilation of Pangea. The second most important period for MVT genesis was Cretaceous to Tertiary Time when microplate assimilation affected the western margin of North America and Africa–Eurasia. There is a notable paucity of MVT lead–zinc ore formation following the breakup of Rodinia and Pangea. Of the five MVT deposits hosted in Proterozoic rocks, only the Nanisivik deposit has been dated as Proterozoic. The contrast in abundance between SEDEX and MVT lead–zinc deposits in the Proterozoic questions the frequently suggested notion that the two types of ores share similar genetic paths. The ages of MVT deposits, when viewed with respect to the orogenic cycle in the adjacent orogen suggest that no single hydrologic model can be universally applied to the migration of the ore fluids. However, topographically driven models best explain most MVT districts. The migration of MVT ore fluids is not a natural consequence of basin evolution; rather, MVT districts formed mainly where platform carbonates had some hydrological connection to orogenic belts. There may be a connection between paleoclimate and the formation of some MVT deposits. This possible relationship is suggested by the dominance of evaporated seawater in fluid inclusions in MVT ores, by hydrological considerations that include the need for multiple-basin volumes of ore fluid to form most MVT districts, and the need for adequate precipitation to provide sufficient topographic head for topographically-driven fluid migration. Paleoclimatic conditions that lead to formation of evaporite conditions but yet have adequate precipitation to form large hydrological systems are most commonly present in low latitudes. For the MVT deposits and districts that have been dated, more than 75% of the combined metal produced are from deposits that have dates that correspond to assembly of Pangea in Devonian through Permian Time. The exceptional endowment of Pangea and especially, North America with MVT lead–zinc deposits may be explained by the following: (1) Laurentia, which formed the core of North America, stayed in low latitudes during the Paleozoic, which allowed the development of vast carbonate platforms; (2) intense orogenic activity during the assembly of Pangea created ground preparation for many MVT districts through far-field deformation of the craton; (3) uplifted orogenic belts along Pangean suture zones established large-scale migration of basin fluids; and (4) the location of Pangea in low latitudes with paleoclimates with high evaporation rates led to the formation of brines by the evaporation of seawater and infiltration of these brines into deep basin aquifers during Pangean orogenic events.
Stanislav Opluštil - One of the best experts on this subject based on the ideXlab platform.
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a review of the middle late pennsylvanian west european regional substages and floral biozones and their correlation to the Geological Time scale based on new u pb ages
Earth-Science Reviews, 2016Co-Authors: Stanislav Opluštil, Mark D. Schmitz, Christopher J. Cleal, Karel MartínekAbstract:Abstract Lower Moscovian (Duckmantian) to lower Asselian ash beds in the continental basins of the central and western Czech Republic have yielded 15 new high-precision U–Pb single crystal zircon CA-ID-TIMS ages. These are used to improve the calibration of the West European regional terrestrial stages and their correlation to the Geological Time Scale. They also allow an improved correlation between the macrofloral biozones that are used for biostratigraphy in the European Pennsylvanian coalfields, the marine biozones on which the global Geological Time Scale was partly established, and the fresh-water and terrestrial faunal biozones. Most of the floral biozones have proved to be essentially isochronous, although the ranges of some individual but stratigraphically important taxa may differ between basins.
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A review of the Middle–Late Pennsylvanian west European regional substages and floral biozones, and their correlation to the Geological Time Scale based on new U–Pb ages
Earth-Science Reviews, 2016Co-Authors: Stanislav Opluštil, Mark D. Schmitz, Christopher J. Cleal, Karel MartínekAbstract:Abstract Lower Moscovian (Duckmantian) to lower Asselian ash beds in the continental basins of the central and western Czech Republic have yielded 15 new high-precision U–Pb single crystal zircon CA-ID-TIMS ages. These are used to improve the calibration of the West European regional terrestrial stages and their correlation to the Geological Time Scale. They also allow an improved correlation between the macrofloral biozones that are used for biostratigraphy in the European Pennsylvanian coalfields, the marine biozones on which the global Geological Time Scale was partly established, and the fresh-water and terrestrial faunal biozones. Most of the floral biozones have proved to be essentially isochronous, although the ranges of some individual but stratigraphically important taxa may differ between basins.
Joyce C Brannon - One of the best experts on this subject based on the ideXlab platform.
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mississippi valley type lead zinc deposits through Geological Time implications from recent age dating research
Mineralium Deposita, 2001Co-Authors: David L. Leach, Michael T. Lewchuk, David T. Symons, Ghislain De Marsily, Dwight C Bradley, Joyce C BrannonAbstract:Remarkable advances in age dating Mississippi Valley-type (MVT) lead–zinc deposits provide a new opportunity to understand how and where these deposits form in the Earth's crust. These dates are summarized and examined in a framework of global tectonics, paleogeography, fluid migration, and paleoclimate. Nineteen districts have been dated by paleomagnetic and/or radiometric methods. Of the districts that have both paleomagnetic and radiometric dates, only the Pine Point and East Tennessee districts have significant disagreements. This broad agreement between paleomagnetic and radiometric dates provides added confidence in the dating techniques used. The new dates confirm the direct connection between the genesis of MVT lead–zinc ores with global-scale tectonic events. The dates show that MVT deposits formed mainly during large contractional tectonic events at restricted Times in the history of the Earth. Only the deposits in the Lennard Shelf of Australia and Nanisivik in Canada have dates that correspond to extensional tectonic events. The most important period for MVT genesis was the Devonian to Permian Time, which corresponds to a series of intense tectonic events during the assimilation of Pangea. The second most important period for MVT genesis was Cretaceous to Tertiary Time when microplate assimilation affected the western margin of North America and Africa–Eurasia. There is a notable paucity of MVT lead–zinc ore formation following the breakup of Rodinia and Pangea. Of the five MVT deposits hosted in Proterozoic rocks, only the Nanisivik deposit has been dated as Proterozoic. The contrast in abundance between SEDEX and MVT lead–zinc deposits in the Proterozoic questions the frequently suggested notion that the two types of ores share similar genetic paths. The ages of MVT deposits, when viewed with respect to the orogenic cycle in the adjacent orogen suggest that no single hydrologic model can be universally applied to the migration of the ore fluids. However, topographically driven models best explain most MVT districts. The migration of MVT ore fluids is not a natural consequence of basin evolution; rather, MVT districts formed mainly where platform carbonates had some hydrological connection to orogenic belts. There may be a connection between paleoclimate and the formation of some MVT deposits. This possible relationship is suggested by the dominance of evaporated seawater in fluid inclusions in MVT ores, by hydrological considerations that include the need for multiple-basin volumes of ore fluid to form most MVT districts, and the need for adequate precipitation to provide sufficient topographic head for topographically-driven fluid migration. Paleoclimatic conditions that lead to formation of evaporite conditions but yet have adequate precipitation to form large hydrological systems are most commonly present in low latitudes. For the MVT deposits and districts that have been dated, more than 75% of the combined metal produced are from deposits that have dates that correspond to assembly of Pangea in Devonian through Permian Time. The exceptional endowment of Pangea and especially, North America with MVT lead–zinc deposits may be explained by the following: (1) Laurentia, which formed the core of North America, stayed in low latitudes during the Paleozoic, which allowed the development of vast carbonate platforms; (2) intense orogenic activity during the assembly of Pangea created ground preparation for many MVT districts through far-field deformation of the craton; (3) uplifted orogenic belts along Pangean suture zones established large-scale migration of basin fluids; and (4) the location of Pangea in low latitudes with paleoclimates with high evaporation rates led to the formation of brines by the evaporation of seawater and infiltration of these brines into deep basin aquifers during Pangean orogenic events.