Paleoecology of Eocene lacustrine varves at Horsefly, British Columbia

1977 ◽  
Vol 14 (5) ◽  
pp. 953-962 ◽  
Author(s):  
M. V. H. Wilson
Keyword(s):  
British Columbia ◽  
Depositional Environment ◽  
Middle Eocene ◽  
Lacustrine Sediments ◽  
Late Summer ◽  
Coarse Grained ◽  
Temperate Climate ◽  
Fish Scales ◽  
Plant Remains ◽  
Warm Temperate

Middle Eocene lacustrine sediments, cropping out in the valley of the Horsefly River, British Columbia, contain abundant fossils of fishes, fish scales, fish coprolites, insects, leaves, and diatoms. The fish scales, insects, and leaves are preserved in at least three sequences of alternating light tuff and dark sapropel laminae, separated stratigraphically by coarse-grained structureless sequences. The proportions of the main types of fossils occurring in the light laminae compared with the dark laminae are significantly different, and are consistent with the hypothesis that the laminations are varves, with dark organic winter laminae and light inorganic summer laminae. Occasional graded sandy layers contain carbonized allochthonous plant remains and represent turbidity deposits caused by storms in the drainage basin.It is proposed here that the varves were deposited in the deeper regions of a stratified, monomictic or meromictic lake in a warm temperate climate. The depositional environment was anaerobic, containing abundant hydrogen sulphide, and was free of turbulence and benthos. Fish were entombed mostly during the winter, insects during the spring and summer, coprolites during the summer, and deciduous leaves during the late summer and autumn. The fish died of starvation and (or) overturn-induced anoxia.

Fossil Mosses from the Bisaccate Zone of the Mid-Eocene Allenby Formation, British Columbia

1974 ◽  
Vol 11 (3) ◽  
pp. 409-421 ◽  
Author(s):  
Marian Kuc
Keyword(s):  
British Columbia ◽  
Middle Eocene ◽  
Plant Tissues ◽  
Plant Remains ◽  
Lake Bottom ◽  
White Colour

New fossil taxa (Ditrichites fylesi, Muscites maycocki, M. ritchiei, Palaeohypnum jovet-asti and P. steerei); unnamed moss and moss-like fossils, detrital fragments of various plant tissues, and paleobotanical evidence of the bisaccate zone are described from the Middle Eocene Allenby Formation near Princeton, British Columbia. These remains occur in laminated, tuffaceous, silty and pyroclastic shale, deposited under lacustrine conditions.Detailed examination of the various laminae indicates that beds of white colour and composed of coarser silt grains are poor in fossils and could be related to periods of decreasing bioproduction; less silty and darker coloured beds are rich in macro- and microfossils and could be related to periods of extensive bioproduction. The rock features, lamination, and distribution of macrofossils indicate the slow and undisturbed accumulation of plant remains on a lake bottom.

Vegetative remains of the Magnoliaceae from the Princeton chert (Middle Eocene) of British Columbia

1990 ◽  
Vol 68 (6) ◽  
pp. 1327-1339 ◽  
Author(s):  
Sergio R. S. Cevallos-Ferriz ◽  
Ruth A. Stockey
Keyword(s):  
British Columbia ◽  
Middle Eocene ◽  
Secondary Growth ◽  
Wood Block ◽  
Secondary Phloem ◽  
Fossil Species ◽  
Bordered Pits ◽  
Phloem Structure ◽  
Perforation Plates ◽  
Warm Temperate

One wood block and many small twigs (up to 1.3 cm diam.) with little secondary growth and showing magnoliaceous characters were identified from the Princeton chert locality (Middle Eocene) of British Columbia, Canada. Specimens were studied with a modified cellulose acetate peel technique and hydrofluoric acid. Well-preserved primary tissues include a chambered pith that distinguishes these twigs from other woods in the chert. Secondary xylem has solitary vessels, radial multiples, and clusters, scalariform perforation plates with 8–27 bars, scalariform, transitional, and opposite intervascular pitting, and tyloses. Imperforate tracheary elements with circular bordered pits, heterocellular and homocellular rays, and marginal parenchyma characterize the twigs. Secondary phloem has dilated rays, alternating bands of fibers and thin-walled cells, and sclerified ray and axial cells. In older wood, opposite intervascular pitting and homocellular rays, suggest affinities with Liriodendron L.; however, the presence of opposite, scalariform, and transitional intervascular pitting and secondary phloem structure necessitate its inclusion in Liriodendroxylon Prakash et al. Liriodendroxylon princetonensis Cevallos-Ferriz et Stockey sp.nov. is distinguished from other species in this genus by the presence of homocellular rays, scalariform intervascular pitting, and well-preserved extraxylary tissues that are unknown for the other fossil species. Liriodendroxylon princetonensis adds to the diversity of extinct magnoliaceous plants during the Eocene and represents the oldest known species of this genus. These plants were probably part of the surrounding forest vegetation in the Princeton basin. Like most extant Magnoliales, L. princetonensis probably lived under subtropical to warm-temperate, moist conditions. Key words: Magnoliaceae, Liriodendroxylon, fossil woods, Eocene.

The Eocene Thomas Ranch flora, Allenby Formation, Princeton, British Columbia, Canada

Botany ◽  
2013 ◽  
Vol 91 (8) ◽  
pp. 514-529 ◽  
Author(s):  
Richard M. Dillhoff ◽  
Thomas A. Dillhoff ◽  
David R. Greenwood ◽  
Melanie L. DeVore ◽  
Kathleen B. Pigg
Keyword(s):  
British Columbia ◽  
Deciduous Forest ◽  
Middle Eocene ◽  
Annual Precipitation ◽  
Temperate Climate ◽  
Mean Annual Precipitation ◽  
Mean Annual Temperature ◽  
Mixed Conifer ◽  
Leaf Analysis ◽  
High Uncertainty

A flora from Thomas Ranch near Princeton, British Columbia, Canada, is assessed for biodiversity and paleoclimate. This latest Early to early Middle Eocene flora occurs in the Allenby Formation. Seventy-six megafossil morphotypes have been recognized, representing at least 62 species, with 29 identified to genus or species. Common taxa include Ginkgo L., Metasequoia Miki, Sequoia Endl., Abies Mill., Pinus L., Pseudolarix Gordon, Acer L., Alnus Mill., Betula L., Fagus L., Sassafras J Presl, Macginitiea Wolfe & Wehr, Prunus L., and Ulmus L. More than 70 pollen and spore types are recognized, 32 of which are assignable to family or genus. The microflora is dominated by conifers (85%–97% abundance), with Betulaceae accounting for most of the angiosperms. The Climate Leaf Analysis Multivariate Program (CLAMP) calculates a mean annual temperature (MAT) of 9.0 ± 1.7 °C and bioclimatic analysis (BA) calculates a MAT of 12.8 ± 2.5 °C. Coldest month mean temperature (CMMT) was >0 °C. Mean annual precipitation (MAP) was >70 cm/year but is estimated with high uncertainty. Both the CLAMP and BA estimates are at the low end of the MAT range previously published for other Okanagan Highland localities, indicating a temperate climate consistent with a mixed conifer–deciduous forest.

Vegetative Remains of the Rosaceae from the Princeton Chert (Middle Eocene) of British Columbia

IAWA Journal ◽  
1990 ◽  
Vol 11 (3) ◽  
pp. 261-280 ◽  
Author(s):  
Sergio R. S. Cevallos-Ferriz ◽  
Ruth A. Stockey
Keyword(s):  
British Columbia ◽  
Middle Eocene ◽  
Anatomical Variation ◽  
Mature Wood ◽  
Temperate Climate ◽  
Anatomical Features ◽  
Bordered Pits ◽  
Vessel Elements

Several anatomieally preserved twigs, a branehing speeimen and the wood of a large axis with affinities to Rosaeeae are deseribed from the Prineeton ehert (Middle Eoeene) of British Columbia, Canada. Speeimens are eharaeterised by a heteroeellular pith with a peri-medullary rone of thiek-walled oval eells and semi-ring-porous seeondary xylem with vertieal traumatie duets, fibres with eireular bordered pits, and mostly seanty paratracheal and oeeasionally apotracheal parenehyma. Ray to vessel pitting is similar to the alternate intervaseular pitting. Seeondary phloem is eomposed of tangentially oriented diseontinuous bands of alternating fibres and thinwalled eells. Seeondary eortical tissues are represented by a phelloderm eharaeterised by rectangular eells and phellern with rectangular eoneave eells. Anatomical variation between speeimens can be related to age of the woody axes. Juvenile and mature wood of this speeies differ in vessel arrangement and presenee of scanty paratracheal parenchyma in mature wood. Vessel elements are arranged in radial multiples, oeeasional clusters as well as solitary vessels. Tyloses and dark cellular contents are present mainly in mature wood. Some twigs have a heterocellular pith with a few scattered cells with dark contents or, occasionally, short irregular rows of these cells. In the branching specimen eells of this type also are organised in longer rows. Together, these anatomical features suggest that all specimens belong to the same taxon, Prunus allenbyensis Cevallos-Ferriz ' Stockey n. sp. Anatomy of this plant reinforces the interpretation of a subtropical to temperate climate during the time of deposition.

Age and depositional environment of the Rock River coal basin, Yukon Territory, Canada

1994 ◽  
Vol 31 (5) ◽  
pp. 865-880 ◽  
Author(s):  
D. G. F. Long ◽  
A. R. Sweet
Keyword(s):  
Depositional Environment ◽  
Middle Eocene ◽  
Late Eocene ◽  
Yukon Territory ◽  
Temperate Climate ◽  
Fluvial System ◽  
Coal Basin ◽  
Early Oligocene ◽  
Palynological Assemblage ◽  
Latest Eocene

Poorly exposed Late Eocene strata in the Rock River basin, 115 km northeast of Watson Lake, accumulated in an intermontane valley with a geometry and history controlled by subsidence associated with the Rock River Fault. The sequence, as seen in one outcrop and five borehole sections, is dominated by drab mudrocks with minor sandstones and some thick lenses of coal. The mudrocks accumulated in floodplain marsh and pond settings associated with a low-gradient, possibly anastomosed, fluvial system. River banks were stable owing to the abundance of plant roots in the channel walls. Although channel sandstone and conglomerate were not identified in the core, the abundance of coarsening- and fining-upwards sets of sandstone of splay origin indicates pronounced levee development. Woody coals accumulated in areas well away from the main channel, in a series of elongate forested swamps, which were periodically inundated by flood water.The overall palynological assemblage is typical of the Eocene and Early Oligocene. A Late Eocene age is inferred from the presence of Gothanipollis in combination with the absence of index species for the Early–Middle Eocene and the latest? Eocene and Oligocene. The low miospore diversity indicates a temperate climate. The dominance of the palynological assemblage by Taxodiaceae–Cupressaceae pollen indicates wet–humid conditions.

scholarly journals Greenhouse conditions in lower Eocene coastal wetlands?—Lessons from Schöningen, Northern Germany

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0232861
Author(s):  
Olaf K. Lenz ◽  
Walter Riegel ◽  
Volker Wilde
Keyword(s):  
Coastal Wetland ◽  
Middle Eocene ◽  
Nutrient Deficiency ◽  
Coastal Vegetation ◽  
Temperate Climate ◽  
Mining District ◽  
Northern Germany ◽  
Lower Eocene ◽  
Successional Stages ◽  
Warm Temperate

The Paleogene succession of the Helmstedt Lignite Mining District in Northern Germany includes coastal peat mire records from the latest Paleocene to the middle Eocene at the southern edge of the Proto-North Sea. Therefore, it covers the different long- and short-term climate perturbations of the Paleogene greenhouse. 56 samples from three individual sections of a lower Eocene seam in the record capture the typical succession of the vegetation in a coastal wetland during a period that was not affected by climate perturbation. This allows facies-dependent vegetational changes to be distinguished from those that were climate induced. Cluster analyses and NMDS of well-preserved palynomorph assemblages reveal four successional stages in the vegetation during peat accumulation: (1) a coastal vegetation, (2) an initial mire, (3) a transitional mire, and (4) a terminal mire. Biodiversity measures show that plant diversity decreased significantly in the successive stages. The highly diverse vegetation at the coast and in the adjacent initial mire was replaced by low diversity communities adapted to wet acidic environments and nutrient deficiency. The palynomorph assemblages are dominated by elements such as Alnus (Betulaceae) or Sphagnum (Sphagnaceae). Typical tropical elements which are characteristic for the middle Eocene part of the succession are missing. This indicates that a more warm-temperate climate prevailed in northwestern Germany during the early lower Eocene.

Palynology of the Eocene Kitsilano Formation, southwest British Columbia

1969 ◽  
Vol 47 (7) ◽  
pp. 1101-1131 ◽  
Author(s):  
William S. Hopkins Jr.
Keyword(s):  
British Columbia ◽  
Late Eocene ◽  
Temperate Climate ◽  
Early Oligocene ◽  
Study Support ◽  
Plant Microfossils ◽  
Warm Temperate

Approximately 55 genera and 75 species of plant microfossils are illustrated and described from the Kitsilano Formation of southwestern British Columbia. The general composition of the flora suggests a humid, warm temperate climate prevailed at time of deposition. Previous work on plant megafossils indicates a late Eocene to possibly early Oligocene age. Plant microfossils recovered in this study support a probable middle to late Eocene age for the Kitsilano Formation.

scholarly journals Late Pleistocene plant macro-fossils from the Gokarna Formation of the Kathmandu Valley, Central Nepal

1970 ◽  
Vol 12 ◽  
pp. 75-88 ◽  
Author(s):  
Sudarshan Bhandari ◽  
Arata Momohara ◽  
Khum N Paudayal
Keyword(s):  
Late Pleistocene ◽  
Large Scale ◽  
Fine Sand ◽  
Middle Part ◽  
Silty Sand ◽  
Coarse Grained ◽  
Temperate Climate ◽  
Kathmandu Valley ◽  
The Common ◽  
Warm Temperate

The Kathmandu Valley offers the best archive to study the Late Pleistocene climate in Nepal. The Gokarna Formation, constituting the middle part of the sedimentary sequence of the Kathmandu Valley comprises alternating layers of carbonaceous clay, silt, massive to parallel and large scale cross stratified, fine to coarse grained sands and occasional gravel layers, deposited at fluvio-deltaic and lacustrine environment. The organic rich layers of clay, silt, silty-sand and micaceous fine sand consists of abundant plant macro-fossils (fruit, seed and leaves). Plant macrofossils assemblage from the Gokarna Formation (thickness 28.5 m, Dhapasi section) in the northern part of the valley consists of 56 taxa from 35 families. Depending upon the available plant, seven macrofossil assemblages, DS-I to DS-VII in ascending order were established. The common tree and shrubs discovered from this section were Eurya, Ficus, Carpinus, Quercus, Alnus, Rubus, Pyracantha, Zizyphus, Carpinus, Boehmeria etc. Carex, Scirpus triqueter, Scirpus, Polygonum, Euphorbia, Oxalis, Mosla, Viola etc. were the common herbaceous taxa. The constant occurrence of subtropical and warm temperate taxa including Eurya, Ficus, Pyracantha and Zizyphus indicated that subtropical and warm temperate climate continued during the deposition of those macrofossil assemblages. However change in the constituents of those taxa and occurrence of taxa indicating cooler climatic condition like conifers and Betula may indicate minor fluctuation of climate during the deposition of the Gokarna Formation.   doi: 10.3126/bdg.v12i0.2252 Bulletin of the Department of Geology, Vol. 12, 2009, pp. 75-88

Metasequoia milleri n.sp., anatomically preserved pollen cones from the Middle Eocene (Allenby Formation) of British Columbia

1979 ◽  
Vol 57 (8) ◽  
pp. 958-970 ◽  
Author(s):  
Gar W. Rothwell ◽  
James F. Basinger
Keyword(s):  
British Columbia ◽  
Middle Eocene ◽  
Metasequoia Glyptostroboides ◽  
Plant Remains ◽  
Exine Ornamentation ◽  
Pollen Sacs ◽  
Pollen Cone ◽  
Fertile Region ◽  
A New Species ◽  
Subtending Leaves

The discovery of well preserved, permineralized plant remains in Eocene sediments near Princeton, British Columbia, provides an opportunity to describe Metasequoia milleri, a new species of taxodiaceous pollen cone. Individual specimens are up to 3.0 mm long and 2.9 mm in diameter and are subtended by a vegetative zone of scale-like leaves. Approximately 30 microsporophylls are attached to the axis, and each bears three ovoid pollen sacs. The distal-most subtending leaves imbricate and enclose the fertile region. Pollen is ovoid to subspheroidal with an erect, protruding leptoma. Grains measure 19–27 μn in diameter and have verrucate exine ornamentation with numerous orbicules. These fossils show that pollen cones anatomically similar to those of extant Metasequoia glyptostroboides were present as early as Middle Eocene time.

The Gang Ranch – Big Bar area, south-central British Columbia: stratigraphy, geochronology, and palynology of the Tertiary beds and their relationship to the Fraser Fault

1984 ◽  
Vol 21 (10) ◽  
pp. 1132-1144 ◽  
Author(s):  
W. H. Mathews ◽  
G. E. Rouse
Keyword(s):  
British Columbia ◽  
Middle Eocene ◽  
Lacustrine Sediments ◽  
Fraser River ◽  
Drainage Pattern ◽  
The West ◽  
West Side ◽  
South Central ◽  
Metavolcanic Rocks ◽  
Fault Trace

Tertiary rocks in the Gang Ranch – Big Bar area, south-central British Columbia, consist of (1) Early or Middle Eocene (50 Ma) lavas, breccias, and tuffs capped by a mappable unit of conglomerate and clays, totalling 1600 m in thickness; (2) Early Miocene basalt and obsidian, only locally present on high summits; (3) Mid-Miocene gravels and tuffs estimated to be up to 300 m thick; and (4) Pliocene "plateau basalts" up to 130 m thick, locally underlain by fluvial and lacustrine sediments. A rich, probably subtropical, palynoassemblage supports the correlation of the first unit with the Kamloops Group of south-central British Columbia, and the palynomorphs from unit (3) indicate equivalence with the Fraser Bend Formation of the Quesnel area.The northwest-trending Fraser Fault transects the area. Eocene and underlying mid-Cretaceous beds are confined to the west side of the fault; Triassic metasediments and metavolcanic rocks form the east wall. The west side of the fault has been structurally lowered by at least 1.6 km in Eocene and(?) later time. Some 70 km of dextral displacement since mid-Cretaceous time is suggested but is not unequivocally demanded. Major movement has occurred since and possibly during deposition of the Eocene beds. Pliocene beds overlying the fault and Mid-Miocene beds adjacent to the fault trace are apparently undisturbed.Pliocene drainage appears to have been northward. Slight northerly tilting has occurred since, but notwithstanding this the southward-flowing Fraser River has become established here. Glacial diversion of an earlier drainage pattern is suspected.

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