Cruziana is a common and widespread trace fossil in Lower Palaeozoic strata that is generally att... more Cruziana is a common and widespread trace fossil in Lower Palaeozoic strata that is generally attributed to the activity of trilobites. The Lower to Middle Ordovician Armorican Quartzite Formation of southern Europe contains well-preserved examples of the Cruziana rugosa Group. This paper outlines how Cruziana forms an important part of the geological heritage in the Villuercas-Ibores-Jara UNESCO Global Geopark, Caceres Province (SW Spain).
T. Palacios1, S. Jensen1, S.M. Barr2, C.E. White3, and R.F. Miller4 1. Area de Palentologia, Facu... more T. Palacios1, S. Jensen1, S.M. Barr2, C.E. White3, and R.F. Miller4 1. Area de Palentologia, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain 06071 ¶ 2. Department of Earth and Environmental Science, Acadia University, Wolfville, NS, Canada B4P 2R6 ¶ 3. Nova Scotia Department of Natural Resources, P.O. Box 698, Halifax, NS, Canada B3J 2T9 ¶ 4. New Brunswick Museum, 277 Douglas Avenue, Saint John, NB, Canada E2K 1E5
C.E. WHite1, T. Palacios2, S. Jensen2, and S.M. Barr3 1. Nova Scotia Department of Natural Resour... more C.E. WHite1, T. Palacios2, S. Jensen2, and S.M. Barr3 1. Nova Scotia Department of Natural Resources, P.O. Box 698, Halifax, Nova Scotia B3J 2T9, Canada ¶ 2. Area de Paleontologia, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06006 Badajoz, Spain ¶ 3. Department of Earth and Environmental Science, Acadia University, Wolfville, Nova Scotia B4P 2R6, Canada
Detailed geological mapping of the Zafra Sector (central Ossa Morena Zone, ZOM) has shown the occ... more Detailed geological mapping of the Zafra Sector (central Ossa Morena Zone, ZOM) has shown the occurrence of a minor synclinal-anticlinal coupled structure compatible with the major structure of the Monesterio Antiform. It has been observed that the Alconera and Zafra units are indeed the same unit, whereas the Los Santos Iimestone corresponds to the Sierra Gorda and Alconera Iimestones. These observations may be done extensive to the whole northern limb of the Monesterio Antiform. A revision of classical tectonic units and stratigraphic sequences, appears, therefore, needed in order to a correct analyse of Lower Paleozoic paleogeography within the Ossa Morena Zone.
The MacCodrum Formation is a classical "lower" Cambrian unit in southeastern Cape Breto... more The MacCodrum Formation is a classical "lower" Cambrian unit in southeastern Cape Breton Island stratigraphy, described since the 1800s. The age of this formation and its correlation with Cambrian units in Avalonian eastern Newfoundland and southern New Brunswick have remained uncertain through numerous revisions. Here we present U-Pb CA-TIMS ages from an ash bed in the basal part of the MacCodrum Formation in its type-section on MacCodrum Brook that fix the maximum time of deposition at 531.86 ± 0.34 Ma. Organic-walled microfossils sampled throughout the MacCodrum Formation type-section yield acritarch taxa identifying the Asteridium-Comasphaerdium Zone, whereas the first acritarchs of the Skiagia-Fimbriaglomerella Zone appear in the overlying Canoe Brook Formation in other sections. The radiometric age and acritarch zonation place the MacCodrum Formation in the upper Fortunian, Cambrian Stage 2. Among trace fossils in the MacCodrum Formation the meandering trace fossil D...
The Cambrian syn-rift strata preserved in western Avalonia provide a distinctive example of how u... more The Cambrian syn-rift strata preserved in western Avalonia provide a distinctive example of how unconformity-bounded sequences are diachronous throughout proximal to marginal rift branches. Terreneuvian‒Miaolingian third-order sequences of the Caledonian Highlands, New Brunswick, Canada, reflect a complex interplay among syn-rift tectonic events, denudation pulses, and sea-level fluctuations. Unconformably overlying the early, rift-related volcanosedimentary Coldbrook Group (ca. 560‒550 Ma), the Ratcliffe Brook, Glen Falls, Hanford Brook, and Forest Hills Formations can be subdivided into two transgressive systems tract (TST)‒highstand systems tract (HST) sequences (each ∼10 m.y.) and an incomplete TST sequence that are separated by stratigraphic gaps. They reflect uplift and tilting events affecting the basement, transgressive and drowning surfaces, and condensed sections. Arid to semi-arid climatic episodes are supported by the excellent preservation of mafic to felsic volcanic cl...
Cambrian acritarchs from the Bourinot belt, Cape Breton Island, Nova Scotia: age and stratigraphi... more Cambrian acritarchs from the Bourinot belt, Cape Breton Island, Nova Scotia: age and stratigraphic implications1
Abstract The detailed record of diagnostic acritarchs from the volcanosedimentary Vallehondo and ... more Abstract The detailed record of diagnostic acritarchs from the volcanosedimentary Vallehondo and Playon formations, bracketed between Cambrian Stage 4 strata bearing the trilobite Serrodiscus and Guzhangian (Miaolingian) beds with Sao aff. hirsuta, allows the establishment of a fine acritarch-based chronostratigraphy. Seven interval zones are defined by the first successive appearances of cosmopolitan index acritarchs, two in Cambrian Series 2 (Skiagia ciliosa and Heliosphaeridium notatum zones) and five in the Miaolingian (Eliasum llaniscum, Cristallinium cambriense, Adara alea, Timofeevia lancarae and Cristallinium dubium zones). The base of the E. llaniscum Zone, which approximates the first appearance of Acadoparadoxides cf. mureroensis, marks a bioevent close to the base of the Wuliuan Stage, and includes an episode of felsic volcanism in the upper member of the Vallehondo Formation. The Cristallinium cambriense Zone is underlain by rhyolites and ignimbrites previously dated at ca. 505 Ma. The base of the Adara alea Zone concurs with the last felsic volcanic episodes in the Vallehondo Formation here dated at 500.9 ± 0.9 Ma. The maximum diversification of acritarchs (A. alea–T. lancarae zones) coincides with the onset of basaltic pillow lava flows in the Playon Formation reflecting a major rifting episode. The recognized acritarch-based zonation is applicable to the Acado-Baltic (biogeographic) Province, and reinforces the great value of acritarchs in Miaolingian chronostratigaphy. The new biostratigraphic data confirm the absence of a Furongian record in the study area and the late Drumian–Guzhangian age (A. alea to C. dubium zones) for one of the main syn-rift episodes recorded in the Ossa-Morena Rift.
Scatarie Island and adjacent Hay Island, located 2 km east of the eastern tip of the Avalonian Mi... more Scatarie Island and adjacent Hay Island, located 2 km east of the eastern tip of the Avalonian Mira terrane of southern Cape Breton Island, Nova Scotia, contain a succession of epiclastic and other sedimentary rocks of inferred Ediacaran to Cambrian age. The age assignment was based previously on lithological comparison with the Main-à-Dieu Group and overlying Bengal Road and MacCodrum formations of the Mira River Group. Detrital zircon grains from two sandstone samples from the Bengal Road Formation yielded typical Avalonian detrital zircon spectra with middle to late Neoproterozoic, Meso- to Paleoproterozoic (1300–2200 Ma) and Neoarchean ages. They indicate maximum depositional ages of 532.4 ± 4.2 Ma and 525.4 ± 2.4 Ma from essentially the same stratigraphic level, consistent with the interpretation that the rocks are Cambrian. The Bengal Road Formation also yielded scarce organic-walled microfossils including an acanthomorphic acritarch identified as Polygonium sp., also consiste...
El comienzo del año 1997 nos trajo una triste noticia, el profesor Gonzalo Vidal había fallecido ... more El comienzo del año 1997 nos trajo una triste noticia, el profesor Gonzalo Vidal había fallecido el 10 de enero en Uppsala (Suecia) a causa de un infarto. Para los que le conocíamos y habíamos tenido el honor de compartir su trabajo, suponía una ausencia irreparable tanto en el sentido personal como en el científico; para la comunidad científica, la perdida de uno de los mejores investigadores que ha dado la ciencia española en el campo de la Paleontología. Sus investigaciones estaban centradas en el estudio de microbiotas de edad Proterozoico-Cámbrico (1.700- 500 Ma.) y su área de investigaci6n abarcaba todo el mundo; como el mismo solía decir, la ciencia aborda problemas cuya solución no depende de las fronteras
Cambrian acritarchs from the Bourinot belt, Cape Breton Island, Nova Scotia: age and stratigraphi... more Cambrian acritarchs from the Bourinot belt, Cape Breton Island, Nova Scotia: age and stratigraphic implications1
Sabellidites cambriensis is a tubular non-mineralized metazoan that appears as compressed ribbon-... more Sabellidites cambriensis is a tubular non-mineralized metazoan that appears as compressed ribbon-shaped imprints with transverse wrinkling, thick walls and an even tube diameter of up to 3 mm. The distribution of Sabellidites is investigated in three Ediacaran–Cambrian sections on the Digermulen Peninsula in Arctic Norway, spanning the Manndrapselva Member of the Stáhpogieddi Formation and the lower member of the Breidvika Formation. Here, the Ediacaran–Cambrian boundary is located in the lower part of the upper parasequence (third cycle) of the Manndrapselva Member. Specimens of Sabellidites are rare but consistently present close to the lowest level of Treptichnus pedum and upsection, whereas the taxon is common and abundant in the lower part of the lower member of the Breidvika Formation, with an upper record at c. 55 m above the base. The range is comparable with that of the GSSP section in Newfoundland, Canada, establishing Sabellidites as an index fossil for the lowermost Camb...
ABSTRACT New trilobites from the upper part of the Pusa Formation (base of Cambrian Stage 3) in C... more ABSTRACT New trilobites from the upper part of the Pusa Formation (base of Cambrian Stage 3) in Central Spain are studied for their systematic and biostratigraphic significance. The trilobites Proabadiella toletana n. gen. et sp., Proabadiella vidalii n. gen. et sp., and a genus et species indet. are recorded with other fossils from the lower Ovetian regional Stage and archaeocyathan Zone I, which had, until now, provided only undetermined trilobites. The Proabadiella morphology is intermediate between that of the oldest genera of trilobites belonging to the families Abadiellidae and Bigotinidae, confirming the old age inferred for the new trilobites co-occurring with the archaeocyathan assemblage. Our findings permit presenting a new trilobite zonation for the lower Ovetian regional Stage (lower Cambrian Stage 3). A correlation is proposed with the other stratigraphically lowermost trilobites recorded globally.
Neoproterozoic-early Cambrian successions in Iberia are reexamined. A gradual transition across t... more Neoproterozoic-early Cambrian successions in Iberia are reexamined. A gradual transition across the Neoproterozoic-Cambrian boundary is present in Central Iberia, whereas in the Cantabrian region and the Iberian Chains Lower Cambrian arenaceous successions rest with profound angular unconformity on Neoproterozoic turbidites. In Central Iberia, the Neoproterozoic sedimentary succession is referred to the informal Domo Extremeño group, representing mostly basinal facies, and the overlying Rio Huso group consisting of slope deposits and proximal turbidites that grade into shallower marine deposits. The latter is inferred to represent distal slope to outer platform depositional conditions and contains widespread carbonate olistostromic units. The position of the Precambrian-Cambrian boundary is within the Pusa shale of the Rio Huso group and can be correlated at the regional level by the occurrence of trace fossils, acritarchs, and in particular the abundant shelly metazoan Cloudina. Th...
Cruziana is a common and widespread trace fossil in Lower Palaeozoic strata that is generally att... more Cruziana is a common and widespread trace fossil in Lower Palaeozoic strata that is generally attributed to the activity of trilobites. The Lower to Middle Ordovician Armorican Quartzite Formation of southern Europe contains well-preserved examples of the Cruziana rugosa Group. This paper outlines how Cruziana forms an important part of the geological heritage in the Villuercas-Ibores-Jara UNESCO Global Geopark, Caceres Province (SW Spain).
T. Palacios1, S. Jensen1, S.M. Barr2, C.E. White3, and R.F. Miller4 1. Area de Palentologia, Facu... more T. Palacios1, S. Jensen1, S.M. Barr2, C.E. White3, and R.F. Miller4 1. Area de Palentologia, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain 06071 ¶ 2. Department of Earth and Environmental Science, Acadia University, Wolfville, NS, Canada B4P 2R6 ¶ 3. Nova Scotia Department of Natural Resources, P.O. Box 698, Halifax, NS, Canada B3J 2T9 ¶ 4. New Brunswick Museum, 277 Douglas Avenue, Saint John, NB, Canada E2K 1E5
C.E. WHite1, T. Palacios2, S. Jensen2, and S.M. Barr3 1. Nova Scotia Department of Natural Resour... more C.E. WHite1, T. Palacios2, S. Jensen2, and S.M. Barr3 1. Nova Scotia Department of Natural Resources, P.O. Box 698, Halifax, Nova Scotia B3J 2T9, Canada ¶ 2. Area de Paleontologia, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06006 Badajoz, Spain ¶ 3. Department of Earth and Environmental Science, Acadia University, Wolfville, Nova Scotia B4P 2R6, Canada
Detailed geological mapping of the Zafra Sector (central Ossa Morena Zone, ZOM) has shown the occ... more Detailed geological mapping of the Zafra Sector (central Ossa Morena Zone, ZOM) has shown the occurrence of a minor synclinal-anticlinal coupled structure compatible with the major structure of the Monesterio Antiform. It has been observed that the Alconera and Zafra units are indeed the same unit, whereas the Los Santos Iimestone corresponds to the Sierra Gorda and Alconera Iimestones. These observations may be done extensive to the whole northern limb of the Monesterio Antiform. A revision of classical tectonic units and stratigraphic sequences, appears, therefore, needed in order to a correct analyse of Lower Paleozoic paleogeography within the Ossa Morena Zone.
The MacCodrum Formation is a classical "lower" Cambrian unit in southeastern Cape Breto... more The MacCodrum Formation is a classical "lower" Cambrian unit in southeastern Cape Breton Island stratigraphy, described since the 1800s. The age of this formation and its correlation with Cambrian units in Avalonian eastern Newfoundland and southern New Brunswick have remained uncertain through numerous revisions. Here we present U-Pb CA-TIMS ages from an ash bed in the basal part of the MacCodrum Formation in its type-section on MacCodrum Brook that fix the maximum time of deposition at 531.86 ± 0.34 Ma. Organic-walled microfossils sampled throughout the MacCodrum Formation type-section yield acritarch taxa identifying the Asteridium-Comasphaerdium Zone, whereas the first acritarchs of the Skiagia-Fimbriaglomerella Zone appear in the overlying Canoe Brook Formation in other sections. The radiometric age and acritarch zonation place the MacCodrum Formation in the upper Fortunian, Cambrian Stage 2. Among trace fossils in the MacCodrum Formation the meandering trace fossil D...
The Cambrian syn-rift strata preserved in western Avalonia provide a distinctive example of how u... more The Cambrian syn-rift strata preserved in western Avalonia provide a distinctive example of how unconformity-bounded sequences are diachronous throughout proximal to marginal rift branches. Terreneuvian‒Miaolingian third-order sequences of the Caledonian Highlands, New Brunswick, Canada, reflect a complex interplay among syn-rift tectonic events, denudation pulses, and sea-level fluctuations. Unconformably overlying the early, rift-related volcanosedimentary Coldbrook Group (ca. 560‒550 Ma), the Ratcliffe Brook, Glen Falls, Hanford Brook, and Forest Hills Formations can be subdivided into two transgressive systems tract (TST)‒highstand systems tract (HST) sequences (each ∼10 m.y.) and an incomplete TST sequence that are separated by stratigraphic gaps. They reflect uplift and tilting events affecting the basement, transgressive and drowning surfaces, and condensed sections. Arid to semi-arid climatic episodes are supported by the excellent preservation of mafic to felsic volcanic cl...
Cambrian acritarchs from the Bourinot belt, Cape Breton Island, Nova Scotia: age and stratigraphi... more Cambrian acritarchs from the Bourinot belt, Cape Breton Island, Nova Scotia: age and stratigraphic implications1
Abstract The detailed record of diagnostic acritarchs from the volcanosedimentary Vallehondo and ... more Abstract The detailed record of diagnostic acritarchs from the volcanosedimentary Vallehondo and Playon formations, bracketed between Cambrian Stage 4 strata bearing the trilobite Serrodiscus and Guzhangian (Miaolingian) beds with Sao aff. hirsuta, allows the establishment of a fine acritarch-based chronostratigraphy. Seven interval zones are defined by the first successive appearances of cosmopolitan index acritarchs, two in Cambrian Series 2 (Skiagia ciliosa and Heliosphaeridium notatum zones) and five in the Miaolingian (Eliasum llaniscum, Cristallinium cambriense, Adara alea, Timofeevia lancarae and Cristallinium dubium zones). The base of the E. llaniscum Zone, which approximates the first appearance of Acadoparadoxides cf. mureroensis, marks a bioevent close to the base of the Wuliuan Stage, and includes an episode of felsic volcanism in the upper member of the Vallehondo Formation. The Cristallinium cambriense Zone is underlain by rhyolites and ignimbrites previously dated at ca. 505 Ma. The base of the Adara alea Zone concurs with the last felsic volcanic episodes in the Vallehondo Formation here dated at 500.9 ± 0.9 Ma. The maximum diversification of acritarchs (A. alea–T. lancarae zones) coincides with the onset of basaltic pillow lava flows in the Playon Formation reflecting a major rifting episode. The recognized acritarch-based zonation is applicable to the Acado-Baltic (biogeographic) Province, and reinforces the great value of acritarchs in Miaolingian chronostratigaphy. The new biostratigraphic data confirm the absence of a Furongian record in the study area and the late Drumian–Guzhangian age (A. alea to C. dubium zones) for one of the main syn-rift episodes recorded in the Ossa-Morena Rift.
Scatarie Island and adjacent Hay Island, located 2 km east of the eastern tip of the Avalonian Mi... more Scatarie Island and adjacent Hay Island, located 2 km east of the eastern tip of the Avalonian Mira terrane of southern Cape Breton Island, Nova Scotia, contain a succession of epiclastic and other sedimentary rocks of inferred Ediacaran to Cambrian age. The age assignment was based previously on lithological comparison with the Main-à-Dieu Group and overlying Bengal Road and MacCodrum formations of the Mira River Group. Detrital zircon grains from two sandstone samples from the Bengal Road Formation yielded typical Avalonian detrital zircon spectra with middle to late Neoproterozoic, Meso- to Paleoproterozoic (1300–2200 Ma) and Neoarchean ages. They indicate maximum depositional ages of 532.4 ± 4.2 Ma and 525.4 ± 2.4 Ma from essentially the same stratigraphic level, consistent with the interpretation that the rocks are Cambrian. The Bengal Road Formation also yielded scarce organic-walled microfossils including an acanthomorphic acritarch identified as Polygonium sp., also consiste...
El comienzo del año 1997 nos trajo una triste noticia, el profesor Gonzalo Vidal había fallecido ... more El comienzo del año 1997 nos trajo una triste noticia, el profesor Gonzalo Vidal había fallecido el 10 de enero en Uppsala (Suecia) a causa de un infarto. Para los que le conocíamos y habíamos tenido el honor de compartir su trabajo, suponía una ausencia irreparable tanto en el sentido personal como en el científico; para la comunidad científica, la perdida de uno de los mejores investigadores que ha dado la ciencia española en el campo de la Paleontología. Sus investigaciones estaban centradas en el estudio de microbiotas de edad Proterozoico-Cámbrico (1.700- 500 Ma.) y su área de investigaci6n abarcaba todo el mundo; como el mismo solía decir, la ciencia aborda problemas cuya solución no depende de las fronteras
Cambrian acritarchs from the Bourinot belt, Cape Breton Island, Nova Scotia: age and stratigraphi... more Cambrian acritarchs from the Bourinot belt, Cape Breton Island, Nova Scotia: age and stratigraphic implications1
Sabellidites cambriensis is a tubular non-mineralized metazoan that appears as compressed ribbon-... more Sabellidites cambriensis is a tubular non-mineralized metazoan that appears as compressed ribbon-shaped imprints with transverse wrinkling, thick walls and an even tube diameter of up to 3 mm. The distribution of Sabellidites is investigated in three Ediacaran–Cambrian sections on the Digermulen Peninsula in Arctic Norway, spanning the Manndrapselva Member of the Stáhpogieddi Formation and the lower member of the Breidvika Formation. Here, the Ediacaran–Cambrian boundary is located in the lower part of the upper parasequence (third cycle) of the Manndrapselva Member. Specimens of Sabellidites are rare but consistently present close to the lowest level of Treptichnus pedum and upsection, whereas the taxon is common and abundant in the lower part of the lower member of the Breidvika Formation, with an upper record at c. 55 m above the base. The range is comparable with that of the GSSP section in Newfoundland, Canada, establishing Sabellidites as an index fossil for the lowermost Camb...
ABSTRACT New trilobites from the upper part of the Pusa Formation (base of Cambrian Stage 3) in C... more ABSTRACT New trilobites from the upper part of the Pusa Formation (base of Cambrian Stage 3) in Central Spain are studied for their systematic and biostratigraphic significance. The trilobites Proabadiella toletana n. gen. et sp., Proabadiella vidalii n. gen. et sp., and a genus et species indet. are recorded with other fossils from the lower Ovetian regional Stage and archaeocyathan Zone I, which had, until now, provided only undetermined trilobites. The Proabadiella morphology is intermediate between that of the oldest genera of trilobites belonging to the families Abadiellidae and Bigotinidae, confirming the old age inferred for the new trilobites co-occurring with the archaeocyathan assemblage. Our findings permit presenting a new trilobite zonation for the lower Ovetian regional Stage (lower Cambrian Stage 3). A correlation is proposed with the other stratigraphically lowermost trilobites recorded globally.
Neoproterozoic-early Cambrian successions in Iberia are reexamined. A gradual transition across t... more Neoproterozoic-early Cambrian successions in Iberia are reexamined. A gradual transition across the Neoproterozoic-Cambrian boundary is present in Central Iberia, whereas in the Cantabrian region and the Iberian Chains Lower Cambrian arenaceous successions rest with profound angular unconformity on Neoproterozoic turbidites. In Central Iberia, the Neoproterozoic sedimentary succession is referred to the informal Domo Extremeño group, representing mostly basinal facies, and the overlying Rio Huso group consisting of slope deposits and proximal turbidites that grade into shallower marine deposits. The latter is inferred to represent distal slope to outer platform depositional conditions and contains widespread carbonate olistostromic units. The position of the Precambrian-Cambrian boundary is within the Pusa shale of the Rio Huso group and can be correlated at the regional level by the occurrence of trace fossils, acritarchs, and in particular the abundant shelly metazoan Cloudina. Th...
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