Pub Date : 2019-02-25DOI: 10.4138/ATLGEOL.2019.001
C. Álvarez-Vázquez
This paper presents a taxonomic revision of filicopsid taxa from the lower to middle Westphalian strata of Nova Scotia and New Brunswick, Maritime Provinces of Canada. Most of the material represents sporadic historical collecting by Geological Survey of Canada (GSC) personnel, and specimens are in the GSC collections in Ottawa. Additional specimens are in the New Brunswick Museum at Saint John, the Fundy Geological Museum at Parrsboro, and the Joggins Fossil Institute at Joggins. Two specimens from outside Canada clarify specific characteristics. The revision involved the detailed examination of 20 adpression (mainly impression) taxa, of which one, Germera brousmicheae, is new. Detailed synonymy lists, with particular focus on records from Canada and the USA, facilitate a refinement of the stratigraphic and geographic distribution of these species. Most of the taxa from the Maritimes are the same as those from other parts of the paleoequatorial belt of Pennsylvanian times. The Maritimes record of filicopsid taxa closely resembles the filicopsid floras of western Europe, most notably the British Isles.
{"title":"Filicopsida from the lower Westphalian (Middle Pennsylvanian) of Nova Scotia and New Brunswick, Maritime Provinces, Canada","authors":"C. Álvarez-Vázquez","doi":"10.4138/ATLGEOL.2019.001","DOIUrl":"https://doi.org/10.4138/ATLGEOL.2019.001","url":null,"abstract":"This paper presents a taxonomic revision of filicopsid taxa from the lower to middle Westphalian strata of Nova Scotia and New Brunswick, Maritime Provinces of Canada. Most of the material represents sporadic historical collecting by Geological Survey of Canada (GSC) personnel, and specimens are in the GSC collections in Ottawa. Additional specimens are in the New Brunswick Museum at Saint John, the Fundy Geological Museum at Parrsboro, and the Joggins Fossil Institute at Joggins. Two specimens from outside Canada clarify specific characteristics. The revision involved the detailed examination of 20 adpression (mainly impression) taxa, of which one, Germera brousmicheae, is new. Detailed synonymy lists, with particular focus on records from Canada and the USA, facilitate a refinement of the stratigraphic and geographic distribution of these species. Most of the taxa from the Maritimes are the same as those from other parts of the paleoequatorial belt of Pennsylvanian times. The Maritimes record of filicopsid taxa closely resembles the filicopsid floras of western Europe, most notably the British Isles.","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2019-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47903630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-28DOI: 10.4138/ATLGEOL.2018.014
T. Alves, N. H. Mattos
{"title":"Structural and depositional controls on Plio-Pleistocene submarine channels: the Taranaki Basin as an analogue for North American continental margins [Abstract]","authors":"T. Alves, N. H. Mattos","doi":"10.4138/ATLGEOL.2018.014","DOIUrl":"https://doi.org/10.4138/ATLGEOL.2018.014","url":null,"abstract":"","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":"1 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2018-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70755375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-08DOI: 10.4138/ATLGEOL.2018.013
S. C. Johnson, S. Barr, D. V. Rooyen, C. White
The Canaan River pluton comprises megacrystic monzogranite and quartz diorite to monzodiorite that is exposed in several small inliers on the Carboniferous New Brunswick Platform west of Moncton in southeastern New Brunswick. Its distinct geophysical signature and borehole data suggest that the Canaan River pluton is part of a large buried felsic to mafic intrusive body that lies at relatively shallow depths beneath flat-lying Pennsylvanian sandstone on the platform. New laser ablation ICP-MS in situ analysis of the megacrystic monzogranite yielded a U-Pb zircon concordia age of 412.6 ± 2.1 Ma, indicating that the intrusion is of Early Devonian (upper Lochkovian) age.The new radiometric data along with lithological, geochemical, and isotopic data suggest that the Canaan River pluton is most like the megacrystic Hawkshaw Granite of upper Lochkovian age in the Pokiok Batholith in southwestern New Brunswick. The similarities shown by these granites suggests that they may have been generated in the same complex tectonomagmatic setting related to the successive arrival of the leading edge of Ganderia and Avalonia at the composite Laurentian margin during the Salinic and Acadian orogenies.
{"title":"U-Pb (zircon) age, petrology, and tectonic setting of the Canaan River pluton, southeastern New Brunswick, Canada","authors":"S. C. Johnson, S. Barr, D. V. Rooyen, C. White","doi":"10.4138/ATLGEOL.2018.013","DOIUrl":"https://doi.org/10.4138/ATLGEOL.2018.013","url":null,"abstract":" The Canaan River pluton comprises megacrystic monzogranite and quartz diorite to monzodiorite that is exposed in several small inliers on the Carboniferous New Brunswick Platform west of Moncton in southeastern New Brunswick. Its distinct geophysical signature and borehole data suggest that the Canaan River pluton is part of a large buried felsic to mafic intrusive body that lies at relatively shallow depths beneath flat-lying Pennsylvanian sandstone on the platform. New laser ablation ICP-MS in situ analysis of the megacrystic monzogranite yielded a U-Pb zircon concordia age of 412.6 ± 2.1 Ma, indicating that the intrusion is of Early Devonian (upper Lochkovian) age.The new radiometric data along with lithological, geochemical, and isotopic data suggest that the Canaan River pluton is most like the megacrystic Hawkshaw Granite of upper Lochkovian age in the Pokiok Batholith in southwestern New Brunswick. The similarities shown by these granites suggests that they may have been generated in the same complex tectonomagmatic setting related to the successive arrival of the leading edge of Ganderia and Avalonia at the composite Laurentian margin during the Salinic and Acadian orogenies. ","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":"1 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2018-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70755360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-26DOI: 10.4138/ATLGEOL.2018.012
A. Ludman, J. Aleinikoff, Henry N Berry Iv, J. Hopeck
SHRIMP U–Pb zircon ages from Ganderia in eastern Maine clarify the ages and provenance of basement units in the Miramichi and St. Croix terranes and of cover rocks in the Fredericton trough and Central Maine/Aroostook-Matapedia basin (CMAM). These new data constrain timing of orogenic events and help understand the origin of the cover rock depocenters.Detrital zircon data generally confirm suggested ages of the formations sampled. Zircon grains with ages of ca. 430 Ma in both depocenters, only slightly older than their host rocks, were probably derived from the earliest volcanic eruptions in the Eastport-Mascarene belt. Their presence indicates that unnamed CMAM sandstone units may be as young as Pridoli and their absence from the Appleton Ridge and Digdeguash formations suggests that these formations are older than initial Eastport-Mascarene volcanism. Detrital and volcanic zircon ages confirm a Late Cambrian to Middle Ordovician age for the Miramichi succession and date Miramichi volcanism at 469.3 ± 4.6 Ma. In the St. Croix terrane, zircon grain with an age of 477.4 ± 3.7 Ma from an ashfall at the base of the Kendall Mountain Formation and age spectra and fossils from overlying quartz arenite suggest that the formation may span Floian to Sandbian time. The main source of CMAM and Fredericton sediment was recycled Ganderian basement from terranes emergent after Late Ordovician orogenesis, supplemented by Silurian tephra. Zircon barcodes and lithofacies and tectonic models suggest little, if any, input from Laurentia or Avalonia.Zircon- and fossil-based ages indicate coeval Upper Ordovician deformation in the St. Croix (ca. 453 to 442 Ma) and Miramichi (ca. 453 to 446 Ma) terranes. Salinic folding in the southeastern Fredericton trough is bracketed between the 421.9 ± 2.4 Ma age of the Pocomoonshine gabbro-diorite and 430 Ma detrital zircons in the Flume Ridge Formation. Zircon ages, lithofacies analysis, and paleontological evidence support the origin of the Fredericton trough as a Salinic foredeep. The CMAM basin cannot have been an Acadian foreland basin, as sedimentation began millions of years before Acadian subduction.
{"title":"SHRIMP U–Pb zircon evidence for age, provenance, and tectonic history of early Paleozoic Ganderian rocks, east-central Maine, USA","authors":"A. Ludman, J. Aleinikoff, Henry N Berry Iv, J. Hopeck","doi":"10.4138/ATLGEOL.2018.012","DOIUrl":"https://doi.org/10.4138/ATLGEOL.2018.012","url":null,"abstract":"SHRIMP U–Pb zircon ages from Ganderia in eastern Maine clarify the ages and provenance of basement units in the Miramichi and St. Croix terranes and of cover rocks in the Fredericton trough and Central Maine/Aroostook-Matapedia basin (CMAM). These new data constrain timing of orogenic events and help understand the origin of the cover rock depocenters.Detrital zircon data generally confirm suggested ages of the formations sampled. Zircon grains with ages of ca. 430 Ma in both depocenters, only slightly older than their host rocks, were probably derived from the earliest volcanic eruptions in the Eastport-Mascarene belt. Their presence indicates that unnamed CMAM sandstone units may be as young as Pridoli and their absence from the Appleton Ridge and Digdeguash formations suggests that these formations are older than initial Eastport-Mascarene volcanism. Detrital and volcanic zircon ages confirm a Late Cambrian to Middle Ordovician age for the Miramichi succession and date Miramichi volcanism at 469.3 ± 4.6 Ma. In the St. Croix terrane, zircon grain with an age of 477.4 ± 3.7 Ma from an ashfall at the base of the Kendall Mountain Formation and age spectra and fossils from overlying quartz arenite suggest that the formation may span Floian to Sandbian time. The main source of CMAM and Fredericton sediment was recycled Ganderian basement from terranes emergent after Late Ordovician orogenesis, supplemented by Silurian tephra. Zircon barcodes and lithofacies and tectonic models suggest little, if any, input from Laurentia or Avalonia.Zircon- and fossil-based ages indicate coeval Upper Ordovician deformation in the St. Croix (ca. 453 to 442 Ma) and Miramichi (ca. 453 to 446 Ma) terranes. Salinic folding in the southeastern Fredericton trough is bracketed between the 421.9 ± 2.4 Ma age of the Pocomoonshine gabbro-diorite and 430 Ma detrital zircons in the Flume Ridge Formation. Zircon ages, lithofacies analysis, and paleontological evidence support the origin of the Fredericton trough as a Salinic foredeep. The CMAM basin cannot have been an Acadian foreland basin, as sedimentation began millions of years before Acadian subduction.","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2018-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44695673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-01DOI: 10.4138/ATLGEOL.2018.011
P. Lyons, Robert G. Sproule
New collections of plant macrofossils provide a precise Middle Pennsylvanian age for the lower Wamsutta Formation red beds of the Narragansett Basin, southeastern Massachusetts, USA. The Wamsutta assemblage indicates strong correlation with the Cumberland Group of the Maritimes Provinces of Canada, which was earlier considered to be of late Langsettian to early Duckmantian age. This correlation is supported by the presence in the Wamsutta Formation of the following plant-fossil species: Neuralethopteris schlehanii, Neuropteris obliqua, Senftenbergia plumosa, Calamites suckowii, Annularia asteris, Annularia cf. microphylla,Asterophyllites charaeformis, Asterophyllites grandis, Asterophyllites lindleyanus, Sphenophyllum cuneifolium, and Sphenopteris valida. Moreover, the new fossil flora resembles the Middle Pennsylvanian florules of western Europe, such as the Laveineopteris loshii Subzone. The new flora is especially similar to those of the Iberian Peninsula, where there is a complete succession of Carboniferous macrofloral zones, and this similarity confirms a late Langsettian or early Duckmantian age for the lower Wamsutta macroflora. The new collections of Wamsutta Formation plant fossils, along with a smaller existing collection, represent the oldest known macroflora in the Narragansett Basin.
{"title":"The fossil flora and age of the Wamsutta red beds (Middle Pennsylvanian), Narragansett Basin, southeastern Massachusetts, USA and correlation with the Cumberland Group of the Maritime Provinces of Canada","authors":"P. Lyons, Robert G. Sproule","doi":"10.4138/ATLGEOL.2018.011","DOIUrl":"https://doi.org/10.4138/ATLGEOL.2018.011","url":null,"abstract":"New collections of plant macrofossils provide a precise Middle Pennsylvanian age for the lower Wamsutta Formation red beds of the Narragansett Basin, southeastern Massachusetts, USA. The Wamsutta assemblage indicates strong correlation with the Cumberland Group of the Maritimes Provinces of Canada, which was earlier considered to be of late Langsettian to early Duckmantian age. This correlation is supported by the presence in the Wamsutta Formation of the following plant-fossil species: Neuralethopteris schlehanii, Neuropteris obliqua, Senftenbergia plumosa, Calamites suckowii, Annularia asteris, Annularia cf. microphylla,Asterophyllites charaeformis, Asterophyllites grandis, Asterophyllites lindleyanus, Sphenophyllum cuneifolium, and Sphenopteris valida. Moreover, the new fossil flora resembles the Middle Pennsylvanian florules of western Europe, such as the Laveineopteris loshii Subzone. The new flora is especially similar to those of the Iberian Peninsula, where there is a complete succession of Carboniferous macrofloral zones, and this similarity confirms a late Langsettian or early Duckmantian age for the lower Wamsutta macroflora. The new collections of Wamsutta Formation plant fossils, along with a smaller existing collection, represent the oldest known macroflora in the Narragansett Basin.","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47378274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-26DOI: 10.4138/ATLGEOL.2018.009
R. Marple, J. Hurd, Lanbo Liu, S. Travis, R. Altamura
High-resolution LiDAR (light detection and ranging) images of northeastern Massachusetts and southeastern New Hampshire reveal a 10-km-long, NW-SE-oriented topographic lineament in northeastern Massachusetts that we interpret to be the surface expression of a SW-dipping thrust fault along which the 1727 Newbury, Massachusetts, earthquake occurred. The Newburyport lineament coincides with the northeast edge of a 10-kmlong, NW-SE-oriented ridge, herein named Merrimack ridge, that parallels the NW-SE-trending segment of the Merrimack River downstream from where it bends 90° to the southeast. The northwestern end of the Newburyport lineament coincides with a 1-km-long, ~7- to 15-m-high, NE-facing Newburyport scarp that is located just south of the bend in the river. The Newburyport lineament also parallels the NW-SE-oriented nodal planes of the focal mechanism that was generated for the 1999 Amesbury, Massachusetts, earthquake. A P-wave velocity tomographic model generated from a seismic-refraction profile across the Newburyport scarp shows a ~40-m-wide low-velocity zone dipping ~41° SW. Velocities along this zone decrease 15–50%, which suggests that the Newburyport lineament is associated with the surface expression of a SW-dipping brittle fault zone. The LiDAR images also revealed three other NW-SE-trending lineaments in the study area.
{"title":"Investigation of the 1727 Newbury, Massachusetts, USA, earthquake using LiDAR imagery and P-wave velocity tomography","authors":"R. Marple, J. Hurd, Lanbo Liu, S. Travis, R. Altamura","doi":"10.4138/ATLGEOL.2018.009","DOIUrl":"https://doi.org/10.4138/ATLGEOL.2018.009","url":null,"abstract":"High-resolution LiDAR (light detection and ranging) images of northeastern Massachusetts and southeastern New Hampshire reveal a 10-km-long, NW-SE-oriented topographic lineament in northeastern Massachusetts that we interpret to be the surface expression of a SW-dipping thrust fault along which the 1727 Newbury, Massachusetts, earthquake occurred. The Newburyport lineament coincides with the northeast edge of a 10-kmlong, NW-SE-oriented ridge, herein named Merrimack ridge, that parallels the NW-SE-trending segment of the Merrimack River downstream from where it bends 90° to the southeast. The northwestern end of the Newburyport lineament coincides with a 1-km-long, ~7- to 15-m-high, NE-facing Newburyport scarp that is located just south of the bend in the river. The Newburyport lineament also parallels the NW-SE-oriented nodal planes of the focal mechanism that was generated for the 1999 Amesbury, Massachusetts, earthquake. A P-wave velocity tomographic model generated from a seismic-refraction profile across the Newburyport scarp shows a ~40-m-wide low-velocity zone dipping ~41° SW. Velocities along this zone decrease 15–50%, which suggests that the Newburyport lineament is associated with the surface expression of a SW-dipping brittle fault zone. The LiDAR images also revealed three other NW-SE-trending lineaments in the study area.","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2018-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48400301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-26DOI: 10.4138/ATLGEOL.2018.010
M. N. Islam, D. Keighley
The area around Penobsquis, east of Sussex, New Brunswick, Canada, is an important location of natural resources for the province. The McCully gas field produces from strata of the Mississippian Horton Group whereas younger strata of the Windsor Group are host to major potash and rocksalt deposits. Overlying these units are over 1 km of poorly understood red beds currently assigned to the Mississippian Mabou Group. To date, this latter unit lacks significant marker beds and has had no useful biostratigraphic recovery, despite recent extraction of close to 5 km of drill core. Research on this core broadly identifies siltstone and sandstone at the base of the Mabou Group that gradually coarsen up into conglomerate. The succession is considered the result of alluvial-fan progradation from the northeast. Within this succession, in several of the cores, is a single interval of localized, horizontally laminated to cross-stratified, bluish-grey sandstone, containing carbonaceous plant fragments and siltstone intraclasts. To assess the importance of this interval in the context of the red bed succession, a total of 131 samples of core from three boreholes have been analyzed using Inductively Coupled Plasma and spectroscopic techniques to determine chemostratigraphy. Study of various elemental ratios can delineate two packages, one that corresponds to the grey interval and overlying red beds, and the other to the underlying red beds. Changes in the elemental ratios are interpreted to mark a broader population of mineral species related to greater variation of provenance and diagenesis in the upper sediment package. The reduced horizons and rip-up clasts may have been produced by sediment reworking along a boundary that represents an unconformity (in core, a disconformity) at a stratigraphic level near to where one has been inferred by other workers.
{"title":"Sedimentology and chemostratigraphy of Carboniferous red beds in the western Moncton Basin, Sussex area, New Brunswick, Canada: possible evidence for a middle Mabou Group unconformity","authors":"M. N. Islam, D. Keighley","doi":"10.4138/ATLGEOL.2018.010","DOIUrl":"https://doi.org/10.4138/ATLGEOL.2018.010","url":null,"abstract":"The area around Penobsquis, east of Sussex, New Brunswick, Canada, is an important location of natural resources for the province. The McCully gas field produces from strata of the Mississippian Horton Group whereas younger strata of the Windsor Group are host to major potash and rocksalt deposits. Overlying these units are over 1 km of poorly understood red beds currently assigned to the Mississippian Mabou Group. To date, this latter unit lacks significant marker beds and has had no useful biostratigraphic recovery, despite recent extraction of close to 5 km of drill core. Research on this core broadly identifies siltstone and sandstone at the base of the Mabou Group that gradually coarsen up into conglomerate. The succession is considered the result of alluvial-fan progradation from the northeast. Within this succession, in several of the cores, is a single interval of localized, horizontally laminated to cross-stratified, bluish-grey sandstone, containing carbonaceous plant fragments and siltstone intraclasts. To assess the importance of this interval in the context of the red bed succession, a total of 131 samples of core from three boreholes have been analyzed using Inductively Coupled Plasma and spectroscopic techniques to determine chemostratigraphy. Study of various elemental ratios can delineate two packages, one that corresponds to the grey interval and overlying red beds, and the other to the underlying red beds. Changes in the elemental ratios are interpreted to mark a broader population of mineral species related to greater variation of provenance and diagenesis in the upper sediment package. The reduced horizons and rip-up clasts may have been produced by sediment reworking along a boundary that represents an unconformity (in core, a disconformity) at a stratigraphic level near to where one has been inferred by other workers.","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2018-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47157909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-25DOI: 10.4138/atlgeol.2018.008
R. Marple, J. Hurd, R. Altamura
Enhancements of recently available high-resolution multibeam echosounder data from the western Gulf of Maine and Atlantic continental margin and light detection and ranging (LiDAR) and digital elevation model data from southeastern Quebec (Canada) and the northeastern United States have revealed numerous ring-shaped morphological features and interpreted small seamounts between the Monteregian Hills igneous province and the New England seamounts. The morphological features onshore are mainly ring-shaped depressions, several of which surround mapped igneous intrusions in the Monteregian Hills igneous province and White Mountain magma series. Most of the rings offshore are also depressions, although a few rings are curved ridges above the seafloor. The largest ring in the western Gulf of Maine is the 30-km-diameter Tillies ring that lies 20 km east of Cape Ann, MA. Several small (<3 km in diameter) round, flat-topped submerged hills that we interpret to be volcanic necks are also present beneath the western Gulf of Maine. The rings between Cape Cod and the continental slope are more subtle because of thicker sediments and poorer spatial resolution of the sonar data in this area. The southernmost ring-shaped features are located on the continental slope and upper continental rise and coincide with the northwestern end of the New England seamount chain. The concentration of these features between the Monteregian Hills igneous province and the New England seamounts suggests that they are igneous features that may be associated with the New England hotspot track.
{"title":"Ring-shaped morphological features and interpreted small seamounts between southern Quebec (Canada) and the New England seamounts (USA) and their possible association with the New England hotspot track","authors":"R. Marple, J. Hurd, R. Altamura","doi":"10.4138/atlgeol.2018.008","DOIUrl":"https://doi.org/10.4138/atlgeol.2018.008","url":null,"abstract":" Enhancements of recently available high-resolution multibeam echosounder data from the western Gulf of Maine and Atlantic continental margin and light detection and ranging (LiDAR) and digital elevation model data from southeastern Quebec (Canada) and the northeastern United States have revealed numerous ring-shaped morphological features and interpreted small seamounts between the Monteregian Hills igneous province and the New England seamounts. The morphological features onshore are mainly ring-shaped depressions, several of which surround mapped igneous intrusions in the Monteregian Hills igneous province and White Mountain magma series. Most of the rings offshore are also depressions, although a few rings are curved ridges above the seafloor. The largest ring in the western Gulf of Maine is the 30-km-diameter Tillies ring that lies 20 km east of Cape Ann, MA. Several small (<3 km in diameter) round, flat-topped submerged hills that we interpret to be volcanic necks are also present beneath the western Gulf of Maine. The rings between Cape Cod and the continental slope are more subtle because of thicker sediments and poorer spatial resolution of the sonar data in this area. The southernmost ring-shaped features are located on the continental slope and upper continental rise and coincide with the northwestern end of the New England seamount chain. The concentration of these features between the Monteregian Hills igneous province and the New England seamounts suggests that they are igneous features that may be associated with the New England hotspot track. ","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2018-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47691793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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