Pub Date : 2015-09-07DOI: 10.4138/ATLGEOL.2015.012
S. Donovan
Antillean ichnology was essentially a blank book when Ron Pickerill of the University of New Brunswick, Fredericton, made his first research visit to Jamaica in February 1990. Ron’s first Jamaican trace-fossil research team worked initially on the Paleogene Richmond Formation, a flysch succession. Subsequent fieldwork examined the diverse sedimentary formations of the Neogene Coastal Group. Ron’s encyclopaedic knowledge of ichnotaxonomy and his enthusiasm for fieldwork led the team in many directions. Investigations were integrated with new studies of the island’s sedimentology and paleontology. For example, the description of the ichnology and sedimentology of the Upper Pliocene Bowden Formation, including the internationally famous Bowden shell bed, was part of a much wider study. The case-hardened rocks of the White Limestone Group discouraged detailed study until Donovan Blissett attacked the diverse ichnobiota of these user-unfriendly rocks for his doctorate under Ron’s supervision at the University of New Brunswick. Carriacou in the Grenadines was the other island to receive detailed examination in terms of its ichnofauna by Ron and his co-workers. The east coast of this small island provides a near-continuous exposure of the deep water succession of the Grand Bay Formation. Deeper-water burrows and borings in allochthonous bioclasts derived from the shallow shelf provide ichnological contrast in this formation.
1990年2月，弗雷德里克顿新不伦瑞克大学的Ron Pickerill首次对牙买加进行研究访问时，安的列斯群岛的技术基本上是一本空白的书。罗恩的第一个牙买加痕迹化石研究小组最初研究的是古近系里士满组，这是一个复理石群。随后的野外工作考察了新近纪海岸群的多种沉积地层。罗恩在技术分类学方面的渊博知识和他对实地工作的热情使团队朝着许多方向发展。调查与岛上沉积学和古生物学的新研究结合在一起。例如，对上新世鲍登组的技术和沉积学的描述，包括国际著名的鲍登壳层，是一个更广泛的研究的一部分。直到多诺万·布利塞特(Donovan Blissett)在新不伦瑞克大学(University of New Brunswick)在罗恩的指导下攻读博士学位时，研究了这些不适合人类使用的岩石的各种鱼生生物群，白色石灰岩群的硬化岩石阻碍了详细的研究。格林纳丁斯的卡里亚库岛是罗恩和他的同事们对其鱼动物群进行详细研究的另一个岛屿。这个小岛的东海岸提供了一个几乎连续不断的大海湾地层的深水序列。来自浅陆架的异域生物碎屑的深水洞和钻孔为该地层提供了技术上的对比。
{"title":"Professor Ron K. Pickerill and the genesis of ichnology in the Antilles (Jamaica and Carriacou)","authors":"S. Donovan","doi":"10.4138/ATLGEOL.2015.012","DOIUrl":"https://doi.org/10.4138/ATLGEOL.2015.012","url":null,"abstract":"Antillean ichnology was essentially a blank book when Ron Pickerill of the University of New Brunswick, Fredericton, made his first research visit to Jamaica in February 1990. Ron’s first Jamaican trace-fossil research team worked initially on the Paleogene Richmond Formation, a flysch succession. Subsequent fieldwork examined the diverse sedimentary formations of the Neogene Coastal Group. Ron’s encyclopaedic knowledge of ichnotaxonomy and his enthusiasm for fieldwork led the team in many directions. Investigations were integrated with new studies of the island’s sedimentology and paleontology. For example, the description of the ichnology and sedimentology of the Upper Pliocene Bowden Formation, including the internationally famous Bowden shell bed, was part of a much wider study. The case-hardened rocks of the White Limestone Group discouraged detailed study until Donovan Blissett attacked the diverse ichnobiota of these user-unfriendly rocks for his doctorate under Ron’s supervision at the University of New Brunswick. Carriacou in the Grenadines was the other island to receive detailed examination in terms of its ichnofauna by Ron and his co-workers. The east coast of this small island provides a near-continuous exposure of the deep water succession of the Grand Bay Formation. Deeper-water burrows and borings in allochthonous bioclasts derived from the shallow shelf provide ichnological contrast in this formation.","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":"51 1","pages":"287-297"},"PeriodicalIF":1.6,"publicationDate":"2015-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70754096","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 : 2015-09-07DOI: 10.4138/atlgeol.2015.013
R. Raeside, A. Tizzard
In the southeastern Cape Breton Highlands Neoproterozoic plutonic and metamorphic rocks outcrop in upland areas whereas Carboniferous sedimentary rocks are found in the river valleys and coastal lowlands. Detailed analysis of the contacts between these two groups of rocks including mapping, geometric constructions of the contact relations, structural geological investigations, petrographic analysis and geophysical map interpretations show that the basement rocks were emplaced by a thrust fault that extends at least from the Baddeck River valley to North River, and possibly includes klippen south and east of the highlands. The thrust fault transported a slab of rock with minimum thickness of 200 m a distance of at least 8 km over Horton and Windsor group rocks. East-directed translation of the thrust block likely occurred during the Alleghanian orogeny, and appears to mirror movement previously identified in the northern and western Cape Breton Highlands, implying that much of the upland geology is allochthonous, but likely rooted in the central highlands as positive flower structure.
{"title":"Basement-cover relations in the southeastern Cape Breton Highlands, Nova Scotia, Canada","authors":"R. Raeside, A. Tizzard","doi":"10.4138/atlgeol.2015.013","DOIUrl":"https://doi.org/10.4138/atlgeol.2015.013","url":null,"abstract":"In the southeastern Cape Breton Highlands Neoproterozoic plutonic and metamorphic rocks outcrop in upland areas whereas Carboniferous sedimentary rocks are found in the river valleys and coastal lowlands. Detailed analysis of the contacts between these two groups of rocks including mapping, geometric constructions of the contact relations, structural geological investigations, petrographic analysis and geophysical map interpretations show that the basement rocks were emplaced by a thrust fault that extends at least from the Baddeck River valley to North River, and possibly includes klippen south and east of the highlands. The thrust fault transported a slab of rock with minimum thickness of 200 m a distance of at least 8 km over Horton and Windsor group rocks. East-directed translation of the thrust block likely occurred during the Alleghanian orogeny, and appears to mirror movement previously identified in the northern and western Cape Breton Highlands, implying that much of the upland geology is allochthonous, but likely rooted in the central highlands as positive flower structure.","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":"51 1","pages":"298-310"},"PeriodicalIF":1.6,"publicationDate":"2015-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70754172","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 : 2015-08-10DOI: 10.4138/ATLGEOL.2015.011
D. Keighley, C. Maher
An assessment of the surface and subsurface geology in New Brunswick has identified several regions, close to Large Final Emitters (industrial sites releasing carbon dioxide, CO 2, into the atmosphere), underlain by large volumes of various sedimentary rocks that could act as either the reservoir or seal in a carbon storage operation. There is a lack of subsurface data with which to make an assessment for the New Brunswick Platform, the Gulf of St. Lawrence, and Northumberland Strait. In the Moncton Basin, the McCully Gas Field is hosted in tight gas sands where it would be difficult to pump down CO 2 at an economical rate. The Stoney Creek Oil and Gas Field south of Moncton is not at sufficient depth for CO 2 to be in a supercritical state, necessary for compressed storage. Saline reservoirs could underlie suitably large areas around these fields, but again there is limited information on the quality of the potential reservoir rock. In the Bay of Fundy, south of Saint John, one borehole indicates a prospective location that includes a saline reservoir with suitable thickness and wireline-calculated porosity and permeability, a seal with suitable thickness, and limited faulting to potentially compartmentalize the reservoir or, conversely, compromise the continuity of the seal. The major uncertainty is trap volume, which is particularly difficult to assess based on the borehole being the only data point within a 50 km radius. This is also an environmentally sensitive offshore area. Until data deficiencies are addressed, no locations can be recommended for carbon storage.
{"title":"A preliminary assessment of carbon storage suitability in deep underground geological formations of New Brunswick, Canada","authors":"D. Keighley, C. Maher","doi":"10.4138/ATLGEOL.2015.011","DOIUrl":"https://doi.org/10.4138/ATLGEOL.2015.011","url":null,"abstract":"An assessment of the surface and subsurface geology in New Brunswick has identified several regions, close to Large Final Emitters (industrial sites releasing carbon dioxide, CO 2, into the atmosphere), underlain by large volumes of various sedimentary rocks that could act as either the reservoir or seal in a carbon storage operation. There is a lack of subsurface data with which to make an assessment for the New Brunswick Platform, the Gulf of St. Lawrence, and Northumberland Strait. In the Moncton Basin, the McCully Gas Field is hosted in tight gas sands where it would be difficult to pump down CO 2 at an economical rate. The Stoney Creek Oil and Gas Field south of Moncton is not at sufficient depth for CO 2 to be in a supercritical state, necessary for compressed storage. Saline reservoirs could underlie suitably large areas around these fields, but again there is limited information on the quality of the potential reservoir rock. In the Bay of Fundy, south of Saint John, one borehole indicates a prospective location that includes a saline reservoir with suitable thickness and wireline-calculated porosity and permeability, a seal with suitable thickness, and limited faulting to potentially compartmentalize the reservoir or, conversely, compromise the continuity of the seal. The major uncertainty is trap volume, which is particularly difficult to assess based on the borehole being the only data point within a 50 km radius. This is also an environmentally sensitive offshore area. Until data deficiencies are addressed, no locations can be recommended for carbon storage.","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":"26 1","pages":"269-286"},"PeriodicalIF":1.6,"publicationDate":"2015-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70754049","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 : 2015-07-30DOI: 10.4138/atlgeol.2015.010
F. Baechler
Cape Breton Island provides a hydrogeological view into the roots of an ancient mountain range, now exhumed, glaciated, and tectonically inactive. It exhibits deep crustal faults and magma chambers associated with formation of the Appalachian mountain belt and the Maritimes Basin during the Paleozoic, as well as Mesozoic rifting relating to the opening of the Atlantic Ocean. Cenozoic exhumation brought these features near surface and into the active groundwater flow field where they were impacted by glaciation and fluctuating sea level. The faults have been important from a societal viewpoint in development of municipal groundwater supplies, controlling inflows to excavations, hydrocarbon exploration, quarry development, and geotechnical investigations. Conceptual models presented here outline fault control on groundwater flow based on seven case studies. Future research should focus on basin-bounding faults in support of managing their role in aquifer development and protection, mountain-front recharge, controlling large-magnitude springs, groundwater–stream interaction, and channel morphology. The hydrogeological importance of these faults has historically been underappreciated.
{"title":"Geology and Hydrogeology of Faults on Cape Breton Island, Nova Scotia, Canada: an overview","authors":"F. Baechler","doi":"10.4138/atlgeol.2015.010","DOIUrl":"https://doi.org/10.4138/atlgeol.2015.010","url":null,"abstract":"Cape Breton Island provides a hydrogeological view into the roots of an ancient mountain range, now exhumed, glaciated, and tectonically inactive. It exhibits deep crustal faults and magma chambers associated with formation of the Appalachian mountain belt and the Maritimes Basin during the Paleozoic, as well as Mesozoic rifting relating to the opening of the Atlantic Ocean. Cenozoic exhumation brought these features near surface and into the active groundwater flow field where they were impacted by glaciation and fluctuating sea level. The faults have been important from a societal viewpoint in development of municipal groundwater supplies, controlling inflows to excavations, hydrocarbon exploration, quarry development, and geotechnical investigations. Conceptual models presented here outline fault control on groundwater flow based on seven case studies. Future research should focus on basin-bounding faults in support of managing their role in aquifer development and protection, mountain-front recharge, controlling large-magnitude springs, groundwater–stream interaction, and channel morphology. The hydrogeological importance of these faults has historically been underappreciated.","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":"51 1","pages":"242-268"},"PeriodicalIF":1.6,"publicationDate":"2015-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70754333","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 : 2015-04-26DOI: 10.4138/ATLGEOL.2015.008
Chris E. White
The 2014 Spring Technical Meeting was once again held in the depths of the Newfoundland winter in the GEO The meeting featured a special session on Monday afternoon entitled “Offshore Petroleum Basins: A New Frontier” which covered a wide range of subjects related to offshore petroleum basins, including geology and geophysics, plate reconstruction, offshore engineering and environmental considerations In addition, general sessions (Monday morning and all day Tuesday) included papers on an eclectic range of topics, as is normally the case at these meetings. and the Question: Measuring the Depth The distribution of Ni-Mg-Fe in olivine is conventionally used to assess if sulfide saturation and segregation of a potentially economic sulfide liquid have occurred in a mafic intrusion. Despite the limited geochemical resolution of this traditional application, olivine multi-trace element studies have never been adopted to expand the geochemical sensitivity of olivine as tracer of multiple ore-forming processes.We present major and trace element data (Ca, Sc, Mg, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, and Zr) that show informative geochemical variability in olivine from both barren and mineralized olivine-gabbro and troctolite lithologies in the Voisey’s Bay (VBI) and Pants Lake intrusions (PLI). Both intrusions have broadly similar lithologies and petrographic characteristics and are approximately coeval (1.34 Ga and 1.32 Ga, respectively) members of the Mesoproterozoic Nain Plutonic Suite. However, the VBI hosts a producing economic Ni-Cu-Co sulfide deposit, whereas in the PLI, although it displays evidence of Ni-Cu sulfide mineralization, a viable ore deposit has not yet been discovered.In general the olivine chemistry in the VBI varies systematically – more primitive (~Fo 77 , ~1,600 ppm Ni) in barren intervals, more evolved (~Fo 62 , ~800 ppm Ni) in mineralized sections – with a pronounced increase in especially Mn (+~7,000 can onshore be used to fingerprint distinct sediment sources show a range of Fe/Al and base-metal values from samples with hydrothermal signatures, indicated by high Fe/Al and base-metal values, to those with noticeable detrital input, indicated by lower Fe/Al and base-metal values. The Lemarchant exhalites have positive shale-normalized Eu anomalies (Eu/Eu* ≥ 1) and negative Ce anomalies (Ce/Ce* ≤1), as well as an Y/Ho ratio of ~27. These values suggest precipitation from reduced, high-temperature hydrothermal vent fluids with a short residence time within the plume and thus, a vent-proximal setting under oxidizing conditions. In-situ analyses of sulfides (euhedral and framboidal pyrite, anhedral chalcopyrite and pyrrhotite, and euhedral arsenopyrite) were determined by secondary ion mass spectroscopy (SIMS). δ34S values from -38 to +8‰ indicate the sulfides have a predominantly diagenetic-biogenic sulfur source and formed under open system conditions with abundant seawater sulfate present. The predominantly biogenic signa
{"title":"Geological Association of Canada Newfoundland Section Abstracts: 2015 Spring Technical Meeting","authors":"Chris E. White","doi":"10.4138/ATLGEOL.2015.008","DOIUrl":"https://doi.org/10.4138/ATLGEOL.2015.008","url":null,"abstract":"The 2014 Spring Technical Meeting was once again held in the depths of the Newfoundland winter in the GEO The meeting featured a special session on Monday afternoon entitled “Offshore Petroleum Basins: A New Frontier” which covered a wide range of subjects related to offshore petroleum basins, including geology and geophysics, plate reconstruction, offshore engineering and environmental considerations In addition, general sessions (Monday morning and all day Tuesday) included papers on an eclectic range of topics, as is normally the case at these meetings. and the Question: Measuring the Depth The distribution of Ni-Mg-Fe in olivine is conventionally used to assess if sulfide saturation and segregation of a potentially economic sulfide liquid have occurred in a mafic intrusion. Despite the limited geochemical resolution of this traditional application, olivine multi-trace element studies have never been adopted to expand the geochemical sensitivity of olivine as tracer of multiple ore-forming processes.We present major and trace element data (Ca, Sc, Mg, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, and Zr) that show informative geochemical variability in olivine from both barren and mineralized olivine-gabbro and troctolite lithologies in the Voisey’s Bay (VBI) and Pants Lake intrusions (PLI). Both intrusions have broadly similar lithologies and petrographic characteristics and are approximately coeval (1.34 Ga and 1.32 Ga, respectively) members of the Mesoproterozoic Nain Plutonic Suite. However, the VBI hosts a producing economic Ni-Cu-Co sulfide deposit, whereas in the PLI, although it displays evidence of Ni-Cu sulfide mineralization, a viable ore deposit has not yet been discovered.In general the olivine chemistry in the VBI varies systematically – more primitive (~Fo 77 , ~1,600 ppm Ni) in barren intervals, more evolved (~Fo 62 , ~800 ppm Ni) in mineralized sections – with a pronounced increase in especially Mn (+~7,000 can onshore be used to fingerprint distinct sediment sources show a range of Fe/Al and base-metal values from samples with hydrothermal signatures, indicated by high Fe/Al and base-metal values, to those with noticeable detrital input, indicated by lower Fe/Al and base-metal values. The Lemarchant exhalites have positive shale-normalized Eu anomalies (Eu/Eu* ≥ 1) and negative Ce anomalies (Ce/Ce* ≤1), as well as an Y/Ho ratio of ~27. These values suggest precipitation from reduced, high-temperature hydrothermal vent fluids with a short residence time within the plume and thus, a vent-proximal setting under oxidizing conditions. In-situ analyses of sulfides (euhedral and framboidal pyrite, anhedral chalcopyrite and pyrrhotite, and euhedral arsenopyrite) were determined by secondary ion mass spectroscopy (SIMS). δ34S values from -38 to +8‰ indicate the sulfides have a predominantly diagenetic-biogenic sulfur source and formed under open system conditions with abundant seawater sulfate present. The predominantly biogenic signa","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":"51 1","pages":"221-232"},"PeriodicalIF":1.6,"publicationDate":"2015-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70754450","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 : 2015-04-22DOI: 10.4138/ATLGEOL.2015.007
B. Broster, P. J. Dickinson
A 67 m near-continuous stratigraphic core was recovered from drilling at Grand Lake Meadows, located near the junction of Grand Lake and the Saint John River, approximately 40 km south of Fredericton, New Brunswick. From analyses of recovered samples and finite radiocarbon dating, four phases of development of the study site and surrounding environs were identified to have occurred following the Late Wisconsinan glacial maximum. Phase I, related to the formation of the DeGeer Sea, commenced more than 15 000 calyBP from deglaciation accompanied by marine transgression. Phase II began ~14 000 calyBP and continued until approximately ~8000 calyBP during which time there was major isostatic readjustment in the region and formation of a stratified, mostly brackish, ancestral Grand Lake and transformation into a mostly freshwater, Lake Acadia. Phase III began shortly after 8000 calyBP and continued until after 3000 calyBP accompanied by return of the Saint John River to a fluvialdominated system after down-cutting an outlet at the Reversing Falls gorge, and draining much of Lake Acadia. During phase IV, ~3000 calyBP to present, estuarine conditions were initiated as marine water advanced upstream over the Reversing Falls, leading to the development of the modern river system and Grand Lake Meadows.
在新不伦瑞克省弗雷德里克顿以南约40公里处，靠近大湖和圣约翰河交界处的Grand Lake Meadows钻井中回收了一个67米的近连续地层岩心。通过对回收样品的分析和有限放射性碳定年，研究地点和周围环境的四个发展阶段被确定为发生在威斯康辛州晚期冰川极大期之后。第一阶段与DeGeer海的形成有关，始于15,000 calyBP以上的消冰期，伴随着海侵。第二阶段开始于~ 14000 calyBP，一直持续到~8000 calyBP，在此期间，该地区发生了重大的均衡调整，形成了一个分层的、以咸淡水为主的祖先大湖，并转变为以淡水为主的阿卡迪亚湖。第三阶段在8000 calyBP之后不久开始，一直持续到3000 calyBP之后，伴随着圣约翰河在逆转瀑布峡谷的一个出口被切断，并排干了阿卡迪亚湖的大部分水，回到了一个以河流为主的系统。在第四期，~3000 calyBP至今，海水在逆转瀑布上游推进，形成了河口条件，导致了现代水系和大草原湖的发展。
{"title":"Late Wisconsinan and Holocene development of Grand Lake Meadows area and southern reaches of the Saint John River Valley, New Brunswick, Canada","authors":"B. Broster, P. J. Dickinson","doi":"10.4138/ATLGEOL.2015.007","DOIUrl":"https://doi.org/10.4138/ATLGEOL.2015.007","url":null,"abstract":"A 67 m near-continuous stratigraphic core was recovered from drilling at Grand Lake Meadows, located near the junction of Grand Lake and the Saint John River, approximately 40 km south of Fredericton, New Brunswick. From analyses of recovered samples and finite radiocarbon dating, four phases of development of the study site and surrounding environs were identified to have occurred following the Late Wisconsinan glacial maximum. Phase I, related to the formation of the DeGeer Sea, commenced more than 15 000 calyBP from deglaciation accompanied by marine transgression. Phase II began ~14 000 calyBP and continued until approximately ~8000 calyBP during which time there was major isostatic readjustment in the region and formation of a stratified, mostly brackish, ancestral Grand Lake and transformation into a mostly freshwater, Lake Acadia. Phase III began shortly after 8000 calyBP and continued until after 3000 calyBP accompanied by return of the Saint John River to a fluvialdominated system after down-cutting an outlet at the Reversing Falls gorge, and draining much of Lake Acadia. During phase IV, ~3000 calyBP to present, estuarine conditions were initiated as marine water advanced upstream over the Reversing Falls, leading to the development of the modern river system and Grand Lake Meadows.","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":"51 1","pages":"206-220"},"PeriodicalIF":1.6,"publicationDate":"2015-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70754443","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 : 2015-04-07DOI: 10.4138/ATLGEOL.2015.006
H. Sues, P. Olsen
The Fundy basin in Nova Scotia and New Brunswick is the largest exposed rift basin of the Newark Supergroup and also extends beneath the Bay of Fundy. Its strata can be divided into four tectonostratigraphic sequences (TS). TS I is represented by the probably Permian Honeycomb Point Formation and possibly the Lepreau Formation. TS II includes the Wolfville Formation with the probably Middle Triassic Economy Member and the early Late Triassic Evangeline Member. These members have yielded markedly different assemblages of continental tetrapods. TS III comprises most of the Blomidon Formation, which is Norian to Rhaetian in age. The Blomidon Formation has yielded few skeletal remains of tetrapods to date but many tetrapod tracks. TS IV includes the late Rhaetian top of the Blomidon Formation and the McCoy Brook Formation, which overlies the North Mountain Basalt and is latest Rhaetian and earliest Jurassic (Hettangian) in age. The McCoy Brook Formation has yielded a diversity of continental tetrapods and lacks any of the characteristic Late Triassic forms. Recent work has correlated the Global Boundary Stratotype Section and Point (GSSP) for the base of the Jurassic (Hettangian) to a level well above the North Mountain Basalt. Thus most of the tetrapod fossils from the McCoy Brook Formation are latest Rhaetian in age, but the higher horizon with skeletal remains of sauropodomorph dinosaurs may be earliest Hettangian in age. The Fundy basin preserves the only known, stratigraphically tightly constrained record of the profound biotic changes in continental ecosystems across the Triassic-Jurassic transition.
{"title":"Stratigraphic and temporal context and faunal diversity of Permian-Jurassic continental tetrapod assemblages from the Fundy rift basin, eastern Canada","authors":"H. Sues, P. Olsen","doi":"10.4138/ATLGEOL.2015.006","DOIUrl":"https://doi.org/10.4138/ATLGEOL.2015.006","url":null,"abstract":"The Fundy basin in Nova Scotia and New Brunswick is the largest exposed rift basin of the Newark Supergroup and also extends beneath the Bay of Fundy. Its strata can be divided into four tectonostratigraphic sequences (TS). TS I is represented by the probably Permian Honeycomb Point Formation and possibly the Lepreau Formation. TS II includes the Wolfville Formation with the probably Middle Triassic Economy Member and the early Late Triassic Evangeline Member. These members have yielded markedly different assemblages of continental tetrapods. TS III comprises most of the Blomidon Formation, which is Norian to Rhaetian in age. The Blomidon Formation has yielded few skeletal remains of tetrapods to date but many tetrapod tracks. TS IV includes the late Rhaetian top of the Blomidon Formation and the McCoy Brook Formation, which overlies the North Mountain Basalt and is latest Rhaetian and earliest Jurassic (Hettangian) in age. The McCoy Brook Formation has yielded a diversity of continental tetrapods and lacks any of the characteristic Late Triassic forms. Recent work has correlated the Global Boundary Stratotype Section and Point (GSSP) for the base of the Jurassic (Hettangian) to a level well above the North Mountain Basalt. Thus most of the tetrapod fossils from the McCoy Brook Formation are latest Rhaetian in age, but the higher horizon with skeletal remains of sauropodomorph dinosaurs may be earliest Hettangian in age. The Fundy basin preserves the only known, stratigraphically tightly constrained record of the profound biotic changes in continental ecosystems across the Triassic-Jurassic transition.","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":"51 1","pages":"139-205"},"PeriodicalIF":1.6,"publicationDate":"2015-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4138/ATLGEOL.2015.006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70754273","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 : 2015-03-24DOI: 10.4138/ATLGEOL.2015.004
J. Waldron, R. Jamieson, H. Pothier, C. White
Fine-grained metasedimentary rocks of the Halifax Group in southern mainland Nova Scotia can be subdivided into mappable units. In Halifax Peninsula, sulphide-rich hornfels, black slate, metasiltstone, and metasandstone of the Cunard Formation are overlain by grey metasedimentary rocks with abundant cross-laminations and local carbonate and calc-silicate concretions, assigned to the Bluestone Quarry Formation. No fossils are known from the Bluestone Quarry Formation but lithological correlatives elsewhere are Tremadocian. The Bluestone Quarry Formation is here divided into four members. The lowest (Point Pleasant member) contains thin parallel-laminated and cross-laminated metasandstone beds with Bouma T bcde and T cde structures, and thicker beds with Bouma ‘a’ divisions. The Black Rock Beach member lacks the thicker massive beds and is dominated by rippled and cross-laminated metasedimentary rocks. The overlying Chain Rock member, an erosion-resistant ridge-forming unit, is disrupted by folds and boudinage. Bedding is truncated at the upper contact, and the internal structures are overprinted by (and therefore predate) the Neoacadian cleavage. They are interpreted as products of synsedimentary mass transport. Scarce folds in the Chain Rock member and current ripples in the underlying unit are consistent with a N or NW transport direction. The overlying Quarry Pond member consists of thinly bedded coherent metasedimentary rocks that generally resemble those of the Black Rock Beach member. Although there are indications of upward shallowing in equivalent successions elsewhere in the Halifax Group, the presence of a major mass transport deposit in the Bluestone Quarry Formation shows that this part of the Halifax Group was deposited on a submarine paleoslope. The failure of geologists to identify this feature in much-visited outcrops testifies to the difficulty of identifying synsedimentary deformation features that have been overprinted by later tectonic deformation.
{"title":"Sedimentary and tectonic setting of a mass-transport slope deposit in the Halifax Group, Halifax Peninsula, Nova Scotia, Canada","authors":"J. Waldron, R. Jamieson, H. Pothier, C. White","doi":"10.4138/ATLGEOL.2015.004","DOIUrl":"https://doi.org/10.4138/ATLGEOL.2015.004","url":null,"abstract":"Fine-grained metasedimentary rocks of the Halifax Group in southern mainland Nova Scotia can be subdivided into mappable units. In Halifax Peninsula, sulphide-rich hornfels, black slate, metasiltstone, and metasandstone of the Cunard Formation are overlain by grey metasedimentary rocks with abundant cross-laminations and local carbonate and calc-silicate concretions, assigned to the Bluestone Quarry Formation. No fossils are known from the Bluestone Quarry Formation but lithological correlatives elsewhere are Tremadocian. The Bluestone Quarry Formation is here divided into four members. The lowest (Point Pleasant member) contains thin parallel-laminated and cross-laminated metasandstone beds with Bouma T bcde and T cde structures, and thicker beds with Bouma ‘a’ divisions. The Black Rock Beach member lacks the thicker massive beds and is dominated by rippled and cross-laminated metasedimentary rocks. The overlying Chain Rock member, an erosion-resistant ridge-forming unit, is disrupted by folds and boudinage. Bedding is truncated at the upper contact, and the internal structures are overprinted by (and therefore predate) the Neoacadian cleavage. They are interpreted as products of synsedimentary mass transport. Scarce folds in the Chain Rock member and current ripples in the underlying unit are consistent with a N or NW transport direction. The overlying Quarry Pond member consists of thinly bedded coherent metasedimentary rocks that generally resemble those of the Black Rock Beach member. Although there are indications of upward shallowing in equivalent successions elsewhere in the Halifax Group, the presence of a major mass transport deposit in the Bluestone Quarry Formation shows that this part of the Halifax Group was deposited on a submarine paleoslope. The failure of geologists to identify this feature in much-visited outcrops testifies to the difficulty of identifying synsedimentary deformation features that have been overprinted by later tectonic deformation.","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":"51 1","pages":"084-104"},"PeriodicalIF":1.6,"publicationDate":"2015-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4138/ATLGEOL.2015.004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70754084","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 : 2015-02-15DOI: 10.4138/ATLGEOL.2015.003
Hayley, D., Pothier, John, F. W., Waldron, Chris, E., White, S., Andrew Dufrane, Rebecca, A., Jamieson
Cambrian to Ordovician metamorphosed clastic sedimentary rocks of the Meguma terrane have no correlatives elsewhere in Atlantic Canada but are similar to successions in North Wales. In the Meguma terrane, the Cambrian Goldenville Group, dominated by sandstone, is overlain by the Halifax Group, consisting mainly of fine-grained slate and siltstone. Within the Halifax Group widespread Furongian black slate units are overlain by greyer units with rare Early Ordovician fossils, assigned to the laterally equivalent Bear River, Feltzen, Bluestone Quarry, Lumsden Dam and Glen Brook formations. The type section of the Bluestone Quarry Formation, here defined, is on Halifax Peninsula, where four constituent members are recognized; the type section of the Lumsden Dam Formation is here defined in the Lumsden Dam region near Wolfville. Detrital zircons extracted from a sample of the Lumsden Dam Formation show a range of ages similar to those displayed by the underlying Goldenville Group, including abundant Neoproterozoic zircon representing Avalonian or Pan-African sources, and a prominent group of peaks between 1.95 and 2.2 Ga, probably representing sources in West Africa. A sample from the Glen Brook Formation east of Halifax shows a similar distribution. In contrast to the correlative Welsh successions, no influx of Mesoproterozoic zircon is seen in Early Ordovician samples, suggesting that, if the two basins were in close proximity in the Cambrian, they had diverged by the Early Ordovician, possibly as a result of strike-slip motion along the margin of Gondwana.
{"title":"Stratigraphy, provenance and tectonic setting of the Lumsden Dam and Bluestone Quarry formations (Lower Ordovician), Halifax Group, Nova Scotia, Canada","authors":"Hayley, D., Pothier, John, F. W., Waldron, Chris, E., White, S., Andrew Dufrane, Rebecca, A., Jamieson","doi":"10.4138/ATLGEOL.2015.003","DOIUrl":"https://doi.org/10.4138/ATLGEOL.2015.003","url":null,"abstract":"Cambrian to Ordovician metamorphosed clastic sedimentary rocks of the Meguma terrane have no correlatives elsewhere in Atlantic Canada but are similar to successions in North Wales. In the Meguma terrane, the Cambrian Goldenville Group, dominated by sandstone, is overlain by the Halifax Group, consisting mainly of fine-grained slate and siltstone. Within the Halifax Group widespread Furongian black slate units are overlain by greyer units with rare Early Ordovician fossils, assigned to the laterally equivalent Bear River, Feltzen, Bluestone Quarry, Lumsden Dam and Glen Brook formations. The type section of the Bluestone Quarry Formation, here defined, is on Halifax Peninsula, where four constituent members are recognized; the type section of the Lumsden Dam Formation is here defined in the Lumsden Dam region near Wolfville. Detrital zircons extracted from a sample of the Lumsden Dam Formation show a range of ages similar to those displayed by the underlying Goldenville Group, including abundant Neoproterozoic zircon representing Avalonian or Pan-African sources, and a prominent group of peaks between 1.95 and 2.2 Ga, probably representing sources in West Africa. A sample from the Glen Brook Formation east of Halifax shows a similar distribution. In contrast to the correlative Welsh successions, no influx of Mesoproterozoic zircon is seen in Early Ordovician samples, suggesting that, if the two basins were in close proximity in the Cambrian, they had diverged by the Early Ordovician, possibly as a result of strike-slip motion along the margin of Gondwana.","PeriodicalId":49235,"journal":{"name":"Atlantic Geology","volume":"51 1","pages":"051-083"},"PeriodicalIF":1.6,"publicationDate":"2015-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4138/ATLGEOL.2015.003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70753726","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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