Volume 23, Number 2, August 1987

EN:

Upper Ordovician to lower Devonian rocks in the Antigonish Highlands, Nova Scotia, consist of biinodal volcanics and redbeds at the base overlain by a thick sequence of fossiliferous marine slliciclastic rocks. These rocks belong to the Arisaig Group and correlate well with coeval rocks to the north of the Antigonish Highlands. The definition of the Arisaig Group is revised to Include the uppermost Ordovician-lowermost Silurian Bears Brook Formation which occurs at the base, and the lower Devonian Knoydart Formation which occurs at the top of the succession.

The sequence as a whnle is probably related to a local rifting event. The Bears Brook Formation consists of continental redbeds and biinodal rift-related volcanic rocks. A marine transgression at. the base of the Silurian is indicated by the first appearance of marine fossiliferous rocks and by the overstep relations exhibited by Silurian strata onto Precambrian basement. The marine transgression may have been associated with a world-wide eustatic rise in sea level and with local rifting. The Knoydart Formation is dominated by fluviatile redbeds indicating a return to subaerial conditions. The distribution of the Arisaig Group rocks around the southern and western margins of the Highlands together with the overstep relationships indicate that the Antigonish Highlands became progressively submerged during the Silurian. This was followed by a return to subaerial conditions In the Early Devonian.

FR:

Dans les Monts Antigonish, les roches de l'Ordovicien superieur au Devonien inferieur comprennent un ensemble inferieur de volcanites bimodales et de llts rouges sur lequel repose une puissante assise de roches fosslliferes marines silicoclastiques. Ces roches appartiennent au Groupe d'Arisaig et peuvent aiseraent etre correlees avec leurs bomologues au nord des Monts Antigonish. On redefinit le Groupe d'Arisaig pour y inclure la Formation de Bears Brook. presente en sa base et s'etageant du sommet de l'Ordovicien au Silurlen basal, ainsi que la Formation de Knoydart, du Devonien inferieur et repartie au sommet de la succession.

Dans son ensemble, la sequence correspond probablement a un episode local de rifting. La Formation de Bears Brook comprend des lits rouges contiuentaux et des volcanites bimodales epparentees au rift. La premiere apparition de roches marines fossillferes et la discordance fondaraentale entre les strates slluriennes et le bati precambrien teraoignent d'une transgression marine a 1'amorce du Sllurien. Cette incursion marine apparalt reliee a une remontee du niveau marin global ainsi qu'a un rifting local. L'importance des llts rouges fluviatlles dans la de Knoydart y atteste d'un retour A des conditions subaerlennes. La distribution des roches du Groupe en bordures meridionale et occidentale des Monts ainsi que leur contact en discordance lndlquent une progressive des Monts Antigonish au cours du Silurlen. L'Eodevonien marque un retour ausc conditions eustatique Formation d'Arisaig submersion subaerlennes

EN:

Late Ordovlcian-Early Silurian flysch slope deposits of the Katapedia Group of tbe Hatapedia Basin on the Tobique River, western New Brunswick, Canada, contain 13 ichnogenera (15 ichnospecies), namely:- Chondrites ichnospp.. Cochlichnus anguineus, Dtctyodora scotica, Dictyodora tenuis, Oiaorphichnus ichnosp., Glockerichnus ichnosp., Gordta marina, Helminthopsis ichnosp., Muensteria ichnosp.. Heonereites uniserialis, Nereites jacksoni. Palaeophycus tubularis. Syncoprutus pharmaceus and Yakutatia emersoni. Of these, Oiaorphichnus. Muensteria and Dictyodora have never previously been recorded in the Hatapedia Basin and Dictyodora is recorded for the first time in North America. The total assemblage represents the most diverse ichnocoenosis yet recorded from Paleozoic slope deposits.

FR:

Sur la riviere Tobique, dans l'ouest du Nouveau-Brunswick,_ au Canada, les flyschs du Groupe de Hatapedia appartenant au Bassin de Hatapedia, deposes en contexte de talus et d'age tardlordovlcien a eosilurien. ont llvre 13 Ichnogenres (15 ichnoespeces). savoir; Chondrites ichnospp., Cochlichnus anguineus, Dictyodora scotica, Dictyodora tenuis, Dimorphichnus Ichnosp.. Glockerichnus ichnosp., Gordia marina. Helminthopsis ichnosp., Muensteria Ichnosp., Heonereites uniserialis, Hereites jacksoni, Palaeophycus tubularis, Syncoprulus pharmaceus and Yakutatia emersoni. Parmi ceux-cl, Dimophichnus. Muensteria et Dictyodora n'ont Jamais ete signales dans le Bassin de Matapedia; 11 sagit. de plus, de la premier decouverte de Dictyodora en Amerique du Nord. Au total, 1'assemblage represente 1'ichnocenose la plus diverse jamais documentee dans les depots de talus de Paleozoique.

EN:

A unique specimen of the trace fossil Rusophycus In the Moydart Formation (Ludlow) of the Slluro-Devonlan Arisaig Group of northeastern Nova Scotia la at least 35 cm long, 18 en wide and 8.5 cm deep. The specimen represents the largest ftusophycus yet described and can truly be regarded as a giant. It Is speculated that the most likely producer of tbe trace fossil was a homalonotld trlloblte.

FR:

La Formation de Moydart (Ludlow) du Groups ailuro-devonien d'Arisaig, au nord-est de la Nouvelle-Ecosse, a livre un exemplalre unique de l'lcbnite ftusophycus aesurant au aolns 35 ca an de long, 18 ca de large et 8.5 ca de prolond. II s'aglt la du plus grand ftusophycus jamais decrlt et l'on eiit done en presence d'un veritable geant. Nous entrevoyons que l'auteur de cette trace a pu etre un trlloblte boaaloootlde.

EN:

The 1987 Symposium of the Atlantic Geoscience Society was held at the Howard Johnson Motor Lodge, Fredericton, New Brunswick on February 6-7, 1987 and was dedi cated to the late Dr. Ernest W. Hale formerly of the Department of Geology, University of New Brunswick. Two workshops were convened on Friday, 6th February:-Metamorphism and Ultrabasic-basic Complexes by John Spray, and Maturation Studies and Petroleum Geology by Graham Williams. Saturday, 7th February was organized into four sessions:- (i) Metallotectonic maps and gold, (ii) Granitoid-related mineral deposits, (iii) Base metal and other economic deposits, and (iv) Non-economical regional studies. A total of 21 papers were given at these sessions, all of which were informative and generally well-presented. Additionally, 11 poster sessions were on display, the quality of which were excellent.

On behalf of the Atlantic Geoscience Society may we thank John Spray for organizing and running such a successful and enjoyable Symposium and Don Bachinski, Arnie McAllister, John Spray and Les Fyffe for acting as chairmen of individual sessions. Last, but not least, we extend our thanks to the many graduate and undergraduate students at the University of New Brunswick for their help in regis tration and ensuring that the meeting ran smoothly, and Rose Northrup for technical assistance.

In the following pages we publish the abstracts of talks and poster sessions given at the meeting.