The Experts below are selected from a list of 12708 Experts worldwide ranked by ideXlab platform
Gilbert Féraud - One of the best experts on this subject based on the ideXlab platform.
-
tectonometamorphic evolution of the southern quebec appalachians 40ar 39ar evidence for middle ordovician crustal thickening and silurian Early Devonian exhumation of the internal humber zone
Geological Society of America Bulletin, 2001Co-Authors: Sébastien Castonguay, Alain Tremblay, Gilles Ruffet, Gilbert FéraudAbstract:Published age data from the Humber zone of the southern Quebec Appalachians indicate that deformation and metamorphism occurred during Middle to Late Ordovician time. This paper presents the results of a regional-scale geochronological study of 70 amphibole and mica single grains by the 40 Ar/ 39 Ar laser step-heating method, which brings forward a more complete Middle Ordovician–Early Devonian tectonometamorphic evolution of the Quebec Appalachian Humber zone. Biotites have plateau ages varying between 420 and 411 Ma. Amphiboles are often compositionally rimmed and/or contain biotite inclusions. Their age spectra are generally disturbed, but may suggest the occurrence of two distinct events: Silurian (429–424 Ma) and Middle Ordovician (462–460 Ma). Two main groups of muscovite ages have been obtained: Middle Ordovician (469–461 Ma) and Silurian–Early Devonian (431–411 Ma), but Middle to Late Devonian (387–376 Ma) ages are also locally present. Middle Ordovician ages are interpreted to record crustal thickening by nappe emplacement during regional Taconian metamorphism. Silurian–Early Devonian ages are attributed to consequences of backthrusting and normal faulting. A statistical analysis of Silurian–Early Devonian muscovite age spectra reveals an irregular decrease in weighted apparent age maxima across the internal Humber zone. This age-decreasing trend is interpreted to result from the temporal (ca. 431–411 Ma) and possibly spatial (northwest to southeast) progression of deformation, recrystallization, and fluid circulation during tectonic exhumation of the internal Humber zone in southern Quebec. Tectonic models for the Northern Appalachian internal Humber zone should take into account the strong body of evidence for Silurian–Early Devonian hinterland-directed and extensional deformation as documented in southern Quebec.
-
Tectonometamorphic evolution of the southern Quebec Appalachians: 40Ar/39Ar evidence for Middle Ordovician crustal thickening and Silurian–Early Devonian exhumation of the internal Humber zone
Geological Society of America Bulletin, 2001Co-Authors: Sébastien Castonguay, Alain Tremblay, Gilles Ruffet, Gilbert FéraudAbstract:Published age data from the Humber zone of the southern Quebec Appalachians indicate that deformation and metamorphism occurred during Middle to Late Ordovician time. This paper presents the results of a regional-scale geochronological study of 70 amphibole and mica single grains by the 40 Ar/ 39 Ar laser step-heating method, which brings forward a more complete Middle Ordovician–Early Devonian tectonometamorphic evolution of the Quebec Appalachian Humber zone. Biotites have plateau ages varying between 420 and 411 Ma. Amphiboles are often compositionally rimmed and/or contain biotite inclusions. Their age spectra are generally disturbed, but may suggest the occurrence of two distinct events: Silurian (429–424 Ma) and Middle Ordovician (462–460 Ma). Two main groups of muscovite ages have been obtained: Middle Ordovician (469–461 Ma) and Silurian–Early Devonian (431–411 Ma), but Middle to Late Devonian (387–376 Ma) ages are also locally present. Middle Ordovician ages are interpreted to record crustal thickening by nappe emplacement during regional Taconian metamorphism. Silurian–Early Devonian ages are attributed to consequences of backthrusting and normal faulting. A statistical analysis of Silurian–Early Devonian muscovite age spectra reveals an irregular decrease in weighted apparent age maxima across the internal Humber zone. This age-decreasing trend is interpreted to result from the temporal (ca. 431–411 Ma) and possibly spatial (northwest to southeast) progression of deformation, recrystallization, and fluid circulation during tectonic exhumation of the internal Humber zone in southern Quebec. Tectonic models for the Northern Appalachian internal Humber zone should take into account the strong body of evidence for Silurian–Early Devonian hinterland-directed and extensional deformation as documented in southern Quebec.
Sébastien Castonguay - One of the best experts on this subject based on the ideXlab platform.
-
tectonometamorphic evolution of the southern quebec appalachians 40ar 39ar evidence for middle ordovician crustal thickening and silurian Early Devonian exhumation of the internal humber zone
Geological Society of America Bulletin, 2001Co-Authors: Sébastien Castonguay, Alain Tremblay, Gilles Ruffet, Gilbert FéraudAbstract:Published age data from the Humber zone of the southern Quebec Appalachians indicate that deformation and metamorphism occurred during Middle to Late Ordovician time. This paper presents the results of a regional-scale geochronological study of 70 amphibole and mica single grains by the 40 Ar/ 39 Ar laser step-heating method, which brings forward a more complete Middle Ordovician–Early Devonian tectonometamorphic evolution of the Quebec Appalachian Humber zone. Biotites have plateau ages varying between 420 and 411 Ma. Amphiboles are often compositionally rimmed and/or contain biotite inclusions. Their age spectra are generally disturbed, but may suggest the occurrence of two distinct events: Silurian (429–424 Ma) and Middle Ordovician (462–460 Ma). Two main groups of muscovite ages have been obtained: Middle Ordovician (469–461 Ma) and Silurian–Early Devonian (431–411 Ma), but Middle to Late Devonian (387–376 Ma) ages are also locally present. Middle Ordovician ages are interpreted to record crustal thickening by nappe emplacement during regional Taconian metamorphism. Silurian–Early Devonian ages are attributed to consequences of backthrusting and normal faulting. A statistical analysis of Silurian–Early Devonian muscovite age spectra reveals an irregular decrease in weighted apparent age maxima across the internal Humber zone. This age-decreasing trend is interpreted to result from the temporal (ca. 431–411 Ma) and possibly spatial (northwest to southeast) progression of deformation, recrystallization, and fluid circulation during tectonic exhumation of the internal Humber zone in southern Quebec. Tectonic models for the Northern Appalachian internal Humber zone should take into account the strong body of evidence for Silurian–Early Devonian hinterland-directed and extensional deformation as documented in southern Quebec.
-
Tectonometamorphic evolution of the southern Quebec Appalachians: 40Ar/39Ar evidence for Middle Ordovician crustal thickening and Silurian–Early Devonian exhumation of the internal Humber zone
Geological Society of America Bulletin, 2001Co-Authors: Sébastien Castonguay, Alain Tremblay, Gilles Ruffet, Gilbert FéraudAbstract:Published age data from the Humber zone of the southern Quebec Appalachians indicate that deformation and metamorphism occurred during Middle to Late Ordovician time. This paper presents the results of a regional-scale geochronological study of 70 amphibole and mica single grains by the 40 Ar/ 39 Ar laser step-heating method, which brings forward a more complete Middle Ordovician–Early Devonian tectonometamorphic evolution of the Quebec Appalachian Humber zone. Biotites have plateau ages varying between 420 and 411 Ma. Amphiboles are often compositionally rimmed and/or contain biotite inclusions. Their age spectra are generally disturbed, but may suggest the occurrence of two distinct events: Silurian (429–424 Ma) and Middle Ordovician (462–460 Ma). Two main groups of muscovite ages have been obtained: Middle Ordovician (469–461 Ma) and Silurian–Early Devonian (431–411 Ma), but Middle to Late Devonian (387–376 Ma) ages are also locally present. Middle Ordovician ages are interpreted to record crustal thickening by nappe emplacement during regional Taconian metamorphism. Silurian–Early Devonian ages are attributed to consequences of backthrusting and normal faulting. A statistical analysis of Silurian–Early Devonian muscovite age spectra reveals an irregular decrease in weighted apparent age maxima across the internal Humber zone. This age-decreasing trend is interpreted to result from the temporal (ca. 431–411 Ma) and possibly spatial (northwest to southeast) progression of deformation, recrystallization, and fluid circulation during tectonic exhumation of the internal Humber zone in southern Quebec. Tectonic models for the Northern Appalachian internal Humber zone should take into account the strong body of evidence for Silurian–Early Devonian hinterland-directed and extensional deformation as documented in southern Quebec.
Nigel H. Trewin - One of the best experts on this subject based on the ideXlab platform.
-
A new Early Devonian trigonotarbid arachnid from the Windyfield Chert, Rhynie, Scotland
Journal of Systematic Palaeontology, 2005Co-Authors: Stephen R. Fayers, Jason A. Dunlop, Nigel H. TrewinAbstract:Synopsis A new, exceptionally preserved, trigonotarbid (Arachnida, Trigonotarbida, Palaeocharin‐idae), Palaeocharinus tuberculatus sp. nov. is described from the Early Devonian (Pragian) Windyfield chert of Rhynie, Aberdeenshire, Scotland, UK. The specimens found are almost twice the size of previous Rhynie palaeocharinids and display an autapomorphic, microtuberculate ornament over the whole body. This tuberculation and possible developing tergite and sternite divisions, which the microtubercles in places appear to define, show significant similarities with the possibly closely related Carboniferous family Anthracomartidae.
-
New gametophytes from the Early Devonian Rhynie chert
Transactions of The Royal Society of Edinburgh-earth Sciences, 2003Co-Authors: Hans Kerp, Nigel H. Trewin, Hagen HassAbstract:Several new gametophytes are described from the Early Devonian Rhynie chert. The new monotypic genus Remyophyton, being the gametophyte of Rhynia, is represented by a dense stand of in situ preserved gametophytes with antheridia- and archegonia-bearing axes. The gametophytes are remarkably small in comparison to those of other Rhynie chert plants. The generic diagnoses of Lyonophyton and Langiophyton are emended to include archegonia- and antheridiabearing axes. All essential stages of the reproductive cycle, i.e. sporophytes, and male and female gametophytes, can now be demonstrated for three of the six land plants from the Rhynie chert, i.e. Rhynia gwynne-vaughanii, Aglaophyton major and Horneophyton lignieri.
-
An Early Devonian arthropod fauna from the Windyfield cherts, Aberdeenshire, Scotland
Palaeontology, 2003Co-Authors: Lyall I. Anderson, Nigel H. TrewinAbstract:New terrestrial and freshwater arthropods are described from the Windyfield cherts, a suite of silicified sinters deposited 700m north-east of the Rhynie cherts and part of the same Early Devonian hot-spring complex. The diverse assemblage consists of Heterocrania rhyniensis (Hirst and Maulik, 1926a), here recognized as a euthycarcinoid; scutigeromorph centipede material assigned to Crussolum sp.; the crustacean Lepidocaris; trigonotarbid arachnids; a new arthropod of myriapod affinities named Leverhulmia mariae gen. et sp. nov.; and the distinctively ornamented arthropod cuticle of Rhynimonstrum dunlopi gen. et sp. nov. The Leverhulmia animal preserves gut content identifying it as an Early terrestrial detritivore. Abundant coprolites of similar composition and morphology to the gut contents of the euthycarcinoid crowd the matrix. Chert texture, faunal associations, and study of modern analogues strongly suggest that the terrestrial arthropods were ubiquitous Early Devonian forms with no particular special adaptation to localized conditions around the terrestrial hot-spring vents. The aquatic arthropods represent biota from ephemeral cool-water pools in the vicinity of the hot-spring vents.
Alain Tremblay - One of the best experts on this subject based on the ideXlab platform.
-
tectonometamorphic evolution of the southern quebec appalachians 40ar 39ar evidence for middle ordovician crustal thickening and silurian Early Devonian exhumation of the internal humber zone
Geological Society of America Bulletin, 2001Co-Authors: Sébastien Castonguay, Alain Tremblay, Gilles Ruffet, Gilbert FéraudAbstract:Published age data from the Humber zone of the southern Quebec Appalachians indicate that deformation and metamorphism occurred during Middle to Late Ordovician time. This paper presents the results of a regional-scale geochronological study of 70 amphibole and mica single grains by the 40 Ar/ 39 Ar laser step-heating method, which brings forward a more complete Middle Ordovician–Early Devonian tectonometamorphic evolution of the Quebec Appalachian Humber zone. Biotites have plateau ages varying between 420 and 411 Ma. Amphiboles are often compositionally rimmed and/or contain biotite inclusions. Their age spectra are generally disturbed, but may suggest the occurrence of two distinct events: Silurian (429–424 Ma) and Middle Ordovician (462–460 Ma). Two main groups of muscovite ages have been obtained: Middle Ordovician (469–461 Ma) and Silurian–Early Devonian (431–411 Ma), but Middle to Late Devonian (387–376 Ma) ages are also locally present. Middle Ordovician ages are interpreted to record crustal thickening by nappe emplacement during regional Taconian metamorphism. Silurian–Early Devonian ages are attributed to consequences of backthrusting and normal faulting. A statistical analysis of Silurian–Early Devonian muscovite age spectra reveals an irregular decrease in weighted apparent age maxima across the internal Humber zone. This age-decreasing trend is interpreted to result from the temporal (ca. 431–411 Ma) and possibly spatial (northwest to southeast) progression of deformation, recrystallization, and fluid circulation during tectonic exhumation of the internal Humber zone in southern Quebec. Tectonic models for the Northern Appalachian internal Humber zone should take into account the strong body of evidence for Silurian–Early Devonian hinterland-directed and extensional deformation as documented in southern Quebec.
-
Tectonometamorphic evolution of the southern Quebec Appalachians: 40Ar/39Ar evidence for Middle Ordovician crustal thickening and Silurian–Early Devonian exhumation of the internal Humber zone
Geological Society of America Bulletin, 2001Co-Authors: Sébastien Castonguay, Alain Tremblay, Gilles Ruffet, Gilbert FéraudAbstract:Published age data from the Humber zone of the southern Quebec Appalachians indicate that deformation and metamorphism occurred during Middle to Late Ordovician time. This paper presents the results of a regional-scale geochronological study of 70 amphibole and mica single grains by the 40 Ar/ 39 Ar laser step-heating method, which brings forward a more complete Middle Ordovician–Early Devonian tectonometamorphic evolution of the Quebec Appalachian Humber zone. Biotites have plateau ages varying between 420 and 411 Ma. Amphiboles are often compositionally rimmed and/or contain biotite inclusions. Their age spectra are generally disturbed, but may suggest the occurrence of two distinct events: Silurian (429–424 Ma) and Middle Ordovician (462–460 Ma). Two main groups of muscovite ages have been obtained: Middle Ordovician (469–461 Ma) and Silurian–Early Devonian (431–411 Ma), but Middle to Late Devonian (387–376 Ma) ages are also locally present. Middle Ordovician ages are interpreted to record crustal thickening by nappe emplacement during regional Taconian metamorphism. Silurian–Early Devonian ages are attributed to consequences of backthrusting and normal faulting. A statistical analysis of Silurian–Early Devonian muscovite age spectra reveals an irregular decrease in weighted apparent age maxima across the internal Humber zone. This age-decreasing trend is interpreted to result from the temporal (ca. 431–411 Ma) and possibly spatial (northwest to southeast) progression of deformation, recrystallization, and fluid circulation during tectonic exhumation of the internal Humber zone in southern Quebec. Tectonic models for the Northern Appalachian internal Humber zone should take into account the strong body of evidence for Silurian–Early Devonian hinterland-directed and extensional deformation as documented in southern Quebec.
Gilles Ruffet - One of the best experts on this subject based on the ideXlab platform.
-
tectonometamorphic evolution of the southern quebec appalachians 40ar 39ar evidence for middle ordovician crustal thickening and silurian Early Devonian exhumation of the internal humber zone
Geological Society of America Bulletin, 2001Co-Authors: Sébastien Castonguay, Alain Tremblay, Gilles Ruffet, Gilbert FéraudAbstract:Published age data from the Humber zone of the southern Quebec Appalachians indicate that deformation and metamorphism occurred during Middle to Late Ordovician time. This paper presents the results of a regional-scale geochronological study of 70 amphibole and mica single grains by the 40 Ar/ 39 Ar laser step-heating method, which brings forward a more complete Middle Ordovician–Early Devonian tectonometamorphic evolution of the Quebec Appalachian Humber zone. Biotites have plateau ages varying between 420 and 411 Ma. Amphiboles are often compositionally rimmed and/or contain biotite inclusions. Their age spectra are generally disturbed, but may suggest the occurrence of two distinct events: Silurian (429–424 Ma) and Middle Ordovician (462–460 Ma). Two main groups of muscovite ages have been obtained: Middle Ordovician (469–461 Ma) and Silurian–Early Devonian (431–411 Ma), but Middle to Late Devonian (387–376 Ma) ages are also locally present. Middle Ordovician ages are interpreted to record crustal thickening by nappe emplacement during regional Taconian metamorphism. Silurian–Early Devonian ages are attributed to consequences of backthrusting and normal faulting. A statistical analysis of Silurian–Early Devonian muscovite age spectra reveals an irregular decrease in weighted apparent age maxima across the internal Humber zone. This age-decreasing trend is interpreted to result from the temporal (ca. 431–411 Ma) and possibly spatial (northwest to southeast) progression of deformation, recrystallization, and fluid circulation during tectonic exhumation of the internal Humber zone in southern Quebec. Tectonic models for the Northern Appalachian internal Humber zone should take into account the strong body of evidence for Silurian–Early Devonian hinterland-directed and extensional deformation as documented in southern Quebec.
-
Tectonometamorphic evolution of the southern Quebec Appalachians: 40Ar/39Ar evidence for Middle Ordovician crustal thickening and Silurian–Early Devonian exhumation of the internal Humber zone
Geological Society of America Bulletin, 2001Co-Authors: Sébastien Castonguay, Alain Tremblay, Gilles Ruffet, Gilbert FéraudAbstract:Published age data from the Humber zone of the southern Quebec Appalachians indicate that deformation and metamorphism occurred during Middle to Late Ordovician time. This paper presents the results of a regional-scale geochronological study of 70 amphibole and mica single grains by the 40 Ar/ 39 Ar laser step-heating method, which brings forward a more complete Middle Ordovician–Early Devonian tectonometamorphic evolution of the Quebec Appalachian Humber zone. Biotites have plateau ages varying between 420 and 411 Ma. Amphiboles are often compositionally rimmed and/or contain biotite inclusions. Their age spectra are generally disturbed, but may suggest the occurrence of two distinct events: Silurian (429–424 Ma) and Middle Ordovician (462–460 Ma). Two main groups of muscovite ages have been obtained: Middle Ordovician (469–461 Ma) and Silurian–Early Devonian (431–411 Ma), but Middle to Late Devonian (387–376 Ma) ages are also locally present. Middle Ordovician ages are interpreted to record crustal thickening by nappe emplacement during regional Taconian metamorphism. Silurian–Early Devonian ages are attributed to consequences of backthrusting and normal faulting. A statistical analysis of Silurian–Early Devonian muscovite age spectra reveals an irregular decrease in weighted apparent age maxima across the internal Humber zone. This age-decreasing trend is interpreted to result from the temporal (ca. 431–411 Ma) and possibly spatial (northwest to southeast) progression of deformation, recrystallization, and fluid circulation during tectonic exhumation of the internal Humber zone in southern Quebec. Tectonic models for the Northern Appalachian internal Humber zone should take into account the strong body of evidence for Silurian–Early Devonian hinterland-directed and extensional deformation as documented in southern Quebec.
