384 research outputs found

    Climate–vegetation models bring fossil forests back to life

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    Earliest history of coal mining and grindstone quarrying at Joggins, Nova Scotia, and its implications for the meaning of the place name “Joggins”

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    The rich history of coal mining and grindstone quarrying at Joggins, Nova Scotia, prior to Lyell’s visit in 1842 is less well known than its subsequent history. Franquelin first observed coal there in 1686, and within little more than a decade Acadian coal mines had sprung up at the Coal Cliffs. Following the British acquisition of Nova Scotia in 1713, the coal mines attracted Captain Belcher and other New England traders, who loaded their ships with coal for sale in Boston. In 1731, eager to impose duty on this unregulated trade, the Nova Scotia Council sponsored a British coal mine at Joggins operated by Major Cope. Unable to safely load ships at the Coal Cliffs, Cope constructed a wharf and coal depot at Gran’choggin (present-day Downing Cove), seven miles to the north of the mine. It was by association with this depot that the Coal Cliffs later became known as Joggins. Cope’s coal mine survived less than eighteen months before the Mi’kmaq, aided and abetted by Acadians, destroyed the site in 1732. Following this episode, Acadians worked the Joggins coal mines until they fell under the control of British forces engaged in the Seven Years War in 1756. Subsequently, the Lords of Trade suppressed coal mining at Joggins, fearing it would harm British imports, and full-scale operations did not recommence until 1847. During this lull, the grindstone industry boomed. Beginning sometime before 1764, the principal stone quarries operated at Lower Cove, where the famous Blue-Grit was cut. Grindstone quarries were also worked on the Maringouin Peninsula and the two opposing sides of Chignecto Bay became known as the North and South Joggins. RÉSUMÉ On connaĂźt moins bien le riche passĂ© de l’extraction du charbon et de la pierre meuliĂšre Ă  Joggins, Nouvelle‑Écosse, avant la visite de Lyell en 1842, que son passĂ© subsĂ©quent. Franquelin y avait observĂ© du charbon pour la premiĂšre fois en 1686 et en l’espace d’un peu plus d’une dĂ©cennie, plusieurs mines de charbon acadiennes Ă©taient apparues Ă  Coal Cliffs. À la suite de l’acquisition de la Nouvelle‑Écosse par les Britanniques en 1713, les mines de charbon ont attirĂ© le capitaine Belcher et d’autres commerçants de la Nouvelle‑Angleterre qui chargeaient leurs vaisseaux de charbon pour le vendre Ă  Boston. En 1731, impatient d’imposer des droits sur ce commerce non rĂ©glementĂ©, le Conseil de la Nouvelle‑Écosse a parrainĂ© l’exploitation Ă  Joggins d’une mine de charbon britannique exploitĂ©e par le major Cope. Incapable de charger de façon sĂ©curitaire les navires Ă  Coal Cliffs, Cope construisit un quai et un dĂ©pĂŽt de charbon Ă  Gran’choggin (anse Downing actuelle), Ă  sept milles au nord de la mine. L’association Ă  ce dĂ©pĂŽt a plus tard confĂ©rĂ© Ă  Coal Cliffs le nom de Joggins. La mine de charbon de Cope a subsistĂ© moins de 18 mois jusqu’à ce que les Micmacs, aidĂ©s et soutenus par les Acadiens, dĂ©truisirent l’emplacement en 1732. AprĂšs cet Ă©pisode, les Acadiens ont exploitĂ© les mines de charbon de Joggins jusqu’à ce qu’elles tombent sous le contrĂŽle des forces britanniques engagĂ©es dans la guerre de Sept Ans en 1756. Les lords du commerce ont subsĂ©quemment supprimĂ© l’extraction du charbon Ă  Joggins, par crainte qu’elle fasse tort aux importations britanniques, et l’exploitation Ă  grande Ă©chelle n’a pas recommencĂ© avant 1847. Pendant cette pĂ©riode d’accalmie, l’industrie de la pierre meuliĂšre a connu un essor notable. Les principales carriĂšres de pierre ont commencĂ© leurs activitĂ©s dans les annĂ©es ayant prĂ©cĂ©dĂ© 1764 Ă  Lower Cove, oĂč l’on extrayait le fameux grĂšs dur bleu. Des carriĂšres de pierre meule ont Ă©galement Ă©tĂ© exploitĂ©es sur la pĂ©ninsule Maringouin et les deux rives opposĂ©es de la baie Chignectou devinrent connues sous les noms de North et South Joggins

    Anatomically-preserved cordaitalean trees from Lower Pennsylvanian (Langsettian) dryland alluvial-plain deposits at Joggins, Nova Scotia

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    Recent discoveries at Joggins, Nova Scotia have altered our understanding of the Pennsylvanian tropical biome. Of particular signiïŹcance has been the recognition of seasonal dryland ecosystems, compositionally distinct from the peat-forming wetland rainforests. Here I describe two anatomically-preserved fossil plant specimens from dryland alluvial plain facies. The ïŹrst specimen, Mesoxylon cf. sutclifïŹ i, is previously unknown from Joggins. It is a septate cordaitalean axis with mesarch leaf traces and a non-sympodial vasculature. Where found as isolated blocks, the secondary xylem of this plant has previously been classiïŹed as Dadoxylon recentium. The axis exhibits subtle growth interruptions suggestive of tropical rainfall seasonality, while associated traumatic zones may record ïŹre-damage. The second specimen is a Dadoxylon stump rooted within well-drained ïŹ‚oodbasin soils. It conïŹrms earlier conjecture, based on parautochthonous assemblages, that cordaitalean trees grew in inter-channel areas. Together these new specimens improve our knowledge of the composition and ecology of seasonal dryland vegetation at Joggins. RÉSUMÉ Des dĂ©couvertes rĂ©centes Ă  Joggins (Nouvelle-Écosse), ont modiïŹĂ© notre comprĂ©hension du biome tropical pennsylvanien. La reconnaissance d'Ă©cosystĂšmes de milieux arides saisonniers aux compositions distinctes des forĂȘts tropicales humides ayant formĂ© des tourbiĂšres, s'avĂšre particuliĂšrement importante. Je dĂ©cris aux prĂ©sentes deux spĂ©cimens prĂ©servĂ©s de plantes fossiles anatomiquement provenant du faciĂšs d'une plaine alluviale de milieu aride. Le premier spĂ©cimen, un Mesoxylon cf. sutclifïŹ i, Ă©tait auparavant inconnu Ă  Joggins. Il s'agit d'un axe cordaitalĂ©en cloisonnĂ© comportant des cicatrices foliaires Ă  arc moyen et une vasculature non sympodiale. Lors de sa dĂ©couverte sous forme de blocs isolĂ©s, on avait prĂ©cĂ©demment classiïŹĂ© le xylĂšme secondaire de cette plante en tant que Dadoxylon recentium L'axe prĂ©sente des interruptions de croissance subtiles Ă©voquant des chutes de pluie tropicales saisonniĂšres, tandis que les cernes traumatiques associĂ©s pourraient tĂ©moigner de dommages causĂ©s par le feu. Le second spĂ©cimen est une souche de Dadoxylon qui plongeait ses racines Ă  l'intĂ©rieur des sols d'un bassin de crue bien drainĂ©. Il conïŹrme une conjecture antĂ©rieure, basĂ©e sur des assemblages parautochtones, supposant que les arbres cordaitalĂ©ens aient poussĂ© dans des secteurs situĂ©s entre des chenaux. Ces deux nouveaux spĂ©cimens amĂ©liorent notre connaissance de la composition et de l'Ă©cologie de la vĂ©gĂ©tation saisonniĂšre des milieux arides Ă  Joggins. [Traduit par la rĂ©daction.

    New Brunswick and Nova Scotia: the First Geological Field Trip by a North American College

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    The first known geological excursion by a North American college was conducted in 1835. Twenty staff and students belonging to Williams College — a liberal arts college in Massachusetts, USA — explored the geology bordering the Bay of Fundy in northeast Maine, New Brunswick and Nova Scotia. Led by two young professors of natural history, Ebenezer Emmons and Albert Hopkins, the party made extensive observations around Pasammaquoddy Bay, Saint John, Parrsboro, and Windsor, as well as more widely through the Minas and Cumberland basins. Although partly following in the footsteps of two pioneering Bostonians, Charles Jackson and Francis Alger, who had reconnoitred the region in the late 1820s, the Williams College party nevertheless made several original observations. One of most important was a study of the anatomy and paleoclimatic significance of permineralized plants from Joggins and Grindstone Island undertaken by Emmons. This was only the second study of its kind worldwide and later inspired William Dawson to do similar work. Largely overlooked by historians of geology, the Williams College expedition, which comprised a four-week voyage of about 1800 km, illustrates well the challenges and opportunities of geological field work in the early Nineteenth Century. RÉSUMÉ La premiĂšre excursion gĂ©ologique connue d’un collĂšge nord‑amĂ©ricain a Ă©tĂ© rĂ©alisĂ©e en 1835. Vingt membres du personnel et Ă©tudiants du CollĂšge Williams — collĂšge d’arts libĂ©raux du Massachusetts, Etats-Unis — ont explorĂ© la gĂ©ologie des bords de la baie de Fundy dans le nord‑est du Maine, au Nouveau‑Brunswick et en Nouvelle‑Écosse. Le groupe dirigĂ© par deux jeunes professeurs d’histoire naturelle, Ebenezer Emmons et Albert Hopkins, a effectuĂ© de nombreuses observations dans les environs de la baie de Passamaquoddy, de Saint‑Jean, de Parrsboro et de Windsor, ainsi que dans des secteurs plus Ă©tendus Ă  l’intĂ©rieur des bassins Minas et Cumberland. MĂȘme si le groupe du CollĂšge Williams a en partie suivi les pas de deux pionniers de Boston, Charles Jackson et Francis Alger, qui avaient effectuĂ© une reconnaissance de la rĂ©gion vers la fin des annĂ©es 1820, il a nĂ©anmoins fait plusieurs observations originales. L’une des plus importantes a Ă©tĂ© l’étude de l’anatomie et de l’importance palĂ©oclimatique des vĂ©gĂ©taux minĂ©ralisĂ©s de Joggins et de l’üle Grindstone rĂ©alisĂ©e par Emmons. Il s’agissait seulement de la deuxiĂšme Ă©tude du genre Ă  l’échelle mondiale; elle a ultĂ©rieurement inspirĂ© Williams Dawson Ă  exĂ©cuter des travaux similaires. Largement nĂ©gligĂ©e par les historiens de gĂ©ologie, l’expĂ©dition du CollĂšge Williams, qui a comportĂ© un voyage de quatre semaines d’environ 1 800 kilomĂštres, illustre bien les dĂ©fis et les possibilitĂ©s qui s’offraient dans le domaine des travaux gĂ©ologiques sur le terrain au dĂ©but du 19e siĂšcle. [Traduit par la redaction

    Evidence for coal forest refugia in the seasonally dry Pennsylvanian tropical lowlands of the Illinois Basin, USA

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    The Moscovian plant macroflora at Cottage Grove southeastern Illinois, USA, is a key example of Pennsylvanian (323–299 Million years ago) dryland vegetation. There is currently no palynological data from the same stratigraphic horizons as the plant macrofossils, leaves and other vegetative and reproductive structures, at this locality. Consequently, reconstructions of the standing vegetation at Cottage Grove from these sediments lack the complementary information and a more regional perspective that can be provided by sporomorphs (prepollen, pollen, megaspores and spores). In order to provide this, we have analysed the composition of fossil sporomorph assemblages in two rock samples taken from macrofossil-bearing inter-coal shale at Cottage Grove. Our palynological data differ considerably in composition and in the dominance-diversity profile from the macrofossil vegetation at this locality. Walchian conifers and pteridosperms are common elements in the macroflora, but are absent in the sporomorph assemblages. Reversely, the sporomorph assemblages at Cottage Grove comprise 17 spore taxa (∌16% and ∌63% of the total assemblages) that are known from the lycopsid orders Isoetales, Lepidodendrales and Selaginallales, while Cottage Grove’s macrofloral record fails to capture evidence of a considerable population of coal forest lycopsids. We interpret our results as evidence that the Pennsylvanian dryland glacial landscape at Cottage Grove included fragmented populations of wetland plants living in refugia

    The oldest Pinus and its preservation by fire

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    Early Cretaceous araucarian driftwood from hemipelagic sediments of the Puez area, South Tyrol, Italy

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    AbstractWe describe a calcareously permineralised fossil tree-trunk, preserved as driftwood, within hemipelagic sediments of the Cretaceous Puez Formation near Wolkenstein, South Tyrol, Italy. Planktic foraminiferal assemblages recovered from the marls containing the fossil wood indicate a latest middle Albian age. Based on its wood anatomy, the trunk is assigned to Agathoxylon and probably has an affinity with the conifer family Araucariaceae. The wood lacks pronounced tree-rings consistent with tree growth within the broad humid tropical belt that existed at that time. The trunk contains cylindrical chambers filled within faecal pellets, demonstrating that oribatid mites infested the tree, either during life, or shortly after death. Prior to final burial, the tree-trunk drifted out into the open sea for a considerable period as indicated by extensive borings assigned to the ichnospecies Teredolites longissimus and produced by teredinid bivalves. Relatively little is known about the Cretaceous floras of Italy, so this new finding fills a gap in our knowledge of the composition and ecology of the vegetation of this region

    Sir William Dawson (1820–1899): a very modern paleobotanist

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    Sir William Dawson was one of Canada’s most influential Nineteenth Century geologists. Although a lifelong opponent of the concept of evolution, a stance that resulted in him being sidelined by the scientific community, he made enormous contributions to Pennsylvanian paleobotany, especially at the Joggins fossil cliffs of Nova Scotia. Key to Dawson’s success was his recognition of the importance of a field-based research program, in which fossil plants could be observed in their precise geological context over a sustained period of time. Uniquely trained as both geologist and botanist, he was skilled in the microscopic analysis of permineralized plant anatomy, and appreciated the enormous potential of fossil charcoal as an untapped source of systematic information. Arguably his most extraordinary insights came in the field of plant taphonomy, in which studies of modern sedimentary processes and environments were used to interpret the rock record. His analysis of fossil plants in their sedimentary context allowed Pennsylvanian coal swamp communities, dominated by lycopsids and calamiteans, to be distinguished from the coniferopsid forests, which occupied mountainous regions further inland. The lasting significance of Dawson’s paleobotanical work is emphasized by many recent papers concerning the Pennsylvanian coal measures of Atlantic Canada, which have either directly built on research topics that Dawson initiated, or have confirmed hypotheses that Dawson framed. Until recent times, the discipline of paleobotany has been dominated by systematic fossil plant description with little or no reference to geological context. By virtue of his distinctively holistic approach, synthesizing all available geological and botanical data, Dawson is marked out from his contemporaries. His methodology does not appear old-fashioned even today, and it is therefore with justification that we describe him as a very modern paleobotanist. ResumĂ© Sir William Dawson a Ă©tĂ© l’un des gĂ©ologues les plus influents du 19e siĂšcle au Canada. MĂȘme s’il s’est opposĂ© toute sa vie au concept de l’évolution, une position qui a amenĂ© le milieu scientifique Ă  l’ignorer, il a Ă©normĂ©ment contribuĂ© Ă  la palĂ©obotanique pennsylvanienne, spĂ©cialement dans les falaises fossilifĂšres de Joggins de la Nouvelle-Écosse. La clĂ© du succĂšs de Dawson rĂ©side dans le fait qu’il avait reconnu l’importance d’un programme de recherche sur le terrain prĂ©voyant l’observation des plantes fossiles dans leur milieu gĂ©ologique particulier pendant une pĂ©riode de temps prolongĂ©e. GrĂące Ă  sa formation unique de gĂ©ologue et de botaniste, il possĂ©dait la compĂ©tence voulue pour rĂ©aliser une analyse microscopique de l’anatomie des plantes perminĂ©ralisĂ©es et il comprenait le potentiel Ă©norme du charbon de bois fossile comme source inexploitĂ©e de donnĂ©es systĂ©matiques. On pourrait soutenir que ses idĂ©es les plus extraordinaires se sont manifestĂ©es dans le domaine de la taphonomie vĂ©gĂ©tale, dans lequel des Ă©tudes d’environnements et de processus sĂ©dimentaires modernes ont servi Ă  interprĂ©ter des antĂ©cĂ©dents lithologiques. Ses analyses de plantes fossiles dans leur contexte sĂ©dimentaire ont permis de distinguer les communautĂ©s des marĂ©cages houillers pennsylvaniens, dans lesquels prĂ©dominent les lycopsides et les calamites, des forĂȘts conifĂ©ropsides, qui occupaient les rĂ©gions montagneuses plus Ă  l’intĂ©rieur des terres. De nombreuses communications rĂ©centes au sujet des couches houillĂšres pennsylvaniennes des provinces de l’Atlantique, qui s’appuient directement sur des sujets de recherches amorcĂ©es par Dawson ou ayant confirmĂ© des hypothĂšses formulĂ©es par Dawson, mettent en relief l’importance durable des travaux palĂ©obotaniques de Dawson. La discipline de la palĂ©obotanique a jusqu’à tout rĂ©cemment Ă©tĂ© dominĂ©e par des descriptions systĂ©matiques de plantes fossiles Ă©voquant Ă  peine ou n’évoquant pas du tout le contexte gĂ©ologique. Dawson s’est dĂ©marquĂ© de ses contemporains au moyen de son approche nettement holistique en rĂ©alisant une synthĂšse de toutes les donnĂ©es gĂ©ologiques et botaniques accessibles. Sa mĂ©thode de travail ne semble pas rĂ©trograde, mĂȘme aujourd’hui, et il est par consĂ©quent tout Ă  fait justifiĂ© que nous le dĂ©crivions en tant que palĂ©obotaniste trĂšs moderne
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