Abstracts
Abstract
The Lower Devonian Wapske Formation of the Tobique Group in the Perth-Andover-Mount Carleton region of north western New Brunswick forms part of the tcctonostratigraphic Tobique Zone. In this region, the formation is 4000 to 9000 m thick and is interpreted as deep-marine turbiditic in origin. Seven sedimentary facies are recognized. These are: conglomerate facies (Facies 1); massive and parallel-laminated sandstone facies (Facies 2); thin- to thick-bedded sandstone with minor mudstone interbeds and/or mud-capped facies (Facies 3); thin-bedded sandstone and mudstone facies (Facies 4); thin-bed ded, graded, fine-grained sandstone facies (Facies S); thin-bedded, fine-grained sandstone and silty mudstone facies (Facies 6); and thin- and medium-bedded siltstone and mudstone facies (Facies 7). These facies are grouped into five facies associa tions reflecting a deep-marine fan system consisting of distributary channels, depositions) lobes, lobe or fan fringes, and intcrchannel areas associated with a basin plain.
A relatively diverse and well-preserved ichnofauna, consisting of 23 ichnogenera (41 ichnospecies) and three vernacular ichnotaxa, is systematically described, these comprising Arthraria Billings, 1872; Bergaueria Prantl, 1945; Chondrites von Sternberg, 1833; Cochlichnus Hitchcock, 18S8; Cosmorhaphe Fuchs, 1895; Cruziana d'Orbigny, 1842; Dendrotichnium Hantzschel, 1975; Didymautichnus Young, 1972, Helminthoida SchafhButl, 1851; Helminthopsis User, 1877; Hormosiroidea Schaffer, 1928; Monomorphichnus Crimes, 1970; Neonereites Scilacher, 1960; Palaeophycus Hall, 1847; Paleodictyon Meneghini in Murchison, 1850; Phycodes Richter, 1850; Protopaleodictyon Ksiqzkiewicz, 1970; Protavirgularia M'Coy, 1850; Rusophycus Hall, 1852; Skolithos Haldeman, 1840; Taenidium Heer, 1877; Uchirites Macsotay, 1967; Umfolozia Savage, 1971; two track forms and indeterminate scratch markings. Their palacoenvironmental distribution within the se quence correlates well with the interpreted submarine fan complex and compares favourably with other previously docu mented ichnofaunas from deep-marine fans. Collectively, the ichnofauna of the Wapske Formation is characteristic of Seilachcr's (1967) Nereites ichnofacies.
RESUME
La formation de Wapske du Devonien inftrieur du groupe de Tobique dans la region de Perth Andover/mont Carleton du nord-ouest du Nouveau-Brunswick fait partie de la zone tectonostratigraphique de Tobique. Dans cette region, la formation a 4 000 a 9 000 m d'6paisseur et elle est interpretee comme une formation d'origine turbiditique abyssale. On reconnait sept facies s&iimentaires, notamment : le conglomerat (facies 1); un facies de gres lamine massif et parallele (facies 2); un facies de gres en couches 6paisses ou minces interstratifie de mudstone en quantity mineure ou couronn£ de boue (facies 3); un facies de mudstone et de gres en couches minces (facies 4); un facies de gres a grains fins, profile^ en couches minces (facies 5); un facies de mudstone vaseux et de gres a grains fins, en couches minces (facies 6); et un facies de mudstone et de microgres en couches minces et moyennes. Ces facies sont groupes en cinq associations de facies cofTCSpondant a un systeme en 6ventail abyssal constituc de dlfluents, dc lobes sedimentaires, de franges en lobe ou en iventail et de zones inter-canaux associ£es a une plaine synclinale.
Une ichnofaune relativement diversified et bien pr£serv£e, constitute de 23 ichnogenres (41 ichnoespeces) et trois ichnotaxa courants, est decrite de facon systematique. Ceux-ci comprennent YArthraria Billings, 1872; le Bergaueria Prantl, 1945; les Chondrites von Sternberg, 1833; le Cochlichnus Hitchcock, 1858; le Cosmorhaphe Fuchs, 1895; le Cruziana d'Orbigny, 1842; le Dendrotichnium Hantzschel, 1975; le Didymaulichnus Young, 1972; YHelminthoida Schafhautl, 1851; YHelminthopsis Heer, 1877; YHormosiroidea Schaffer, 1928; le Monomorphichnus Crimes, 1970; le Neonereites Scilacher, 1960; le Palaeophycus Hall, 1847; le Palaeodictyon Meneghini dans Murchison, 1850; le Phycodes Richter, 1850; le Protopaleodictyon Ksiqzkiewicz, 1970; le Protavirgularia M'Coy, 1850; le Rusophycus Hall, 1852; le Skolithos Haldeman, 1840; le Taenidium Heer, 1877; YVchirites Macsotay, 1967; YUmfolozia Savage, 1971; deux formes de pistes et des marques de grattage. Leur repartition paleoenvironnementale a 1'interieur de la sequence correspond bien avec le complexe en iventail sous-marin interpret et elle se compare favorablement avec les autres ichnofaunes des even tails abyssaux documentecs auparavant. Collectivement, 1'ichnofaune de la formation de Wapske est caracteristique de Pichnofacies Nereites de Scilacher (1967).
Download the article in PDF to read it.
Download