25 research outputs found
Great Canadian Lagerstätten 1. Early Eocene Lagerstätten of the Okanagan Highlands (British Columbia and Washington State)
The Early Eocene Okanagan High lands series of lacustrine shale and coal deposits, in far western North Ameri ca, constitutes a significant group of fossil sites with exceptional preserva tion of a diverse suite of organisms (Lagerstätten). With contemporaneous basins arrayed across about 1000 kilo metres of southern British Columbia and northern Washington, these sites offer a unique opportunity to examine the paleoecology of terrestrial commu nities spanning a temperate, low-sea sonality landscape in a montane setting during a time of generally warm tem peratures across the globe. The Okana gan Highlands sites provide an unpar alleled comparative framework within which to examine this major turning point in terrestrial community develop ment during the emergence of their broad modern character.La série de dépôts lacustres de schiste et de charbon du début de l’Éocène des hautes terres d’Okanagan, aux con fins de l’ouest de l’Amérique du Nord, constituent un groupe important de sites fossiles particulièrement bien con servés de suites d’organismes diverses (Lagerstätten). De nos jours, ces sites forment en une bande d’environ 1 000 kilomètres, depuis le sud de la Colom bie-Britannique jusqu’au nord de l’État de Washington. Dans le contexte de réchauffement climatique, c’est l’occa sion ou jamais d’étudier la paléoécolo gie de communautés terrestres dans des conditions climatiques modérées dans un paysage de montagne à faible saisonnalité. Les sites des hautes terres d’Okanagan représentent un cadre de comparaison sans pareil permettant d’étudier les effets de ce tournant majeur sur le développement des prin cipales caractéristiques modernes de la communauté terrestre
Belowground rhizomes in paleosols:The hidden half of an Early Devonian vascular plant
The colonization of terrestrial environments by rooted vascular plants had far-reaching impacts on the Earth system. However, the belowground structures of early vascular plants are rarely documented, and thus the plant-soil interactions in early terrestrial ecosystems are poorly understood. Here we report the earliest rooted paleosols (fossil soils) in Asia from Early Devonian deposits of Yunnan, China. Plant traces are extensive within the soil and occur as complex network-like structures, which are interpreted as representing long-lived, belowground rhizomes of the basal lycopsid Drepanophycus. The rhizomes produced large clones and helped the plant survive frequent sediment burial in well-drained soils within a seasonal wet-dry climate zone. Rhizome networks contributed to the accumulation and pedogenesis of floodplain sediments and increased the soil stabilizing effects of early plants. Predating the appearance of trees with deep roots in the Middle Devonian, plant rhizomes have long functioned in the belowground soil ecosystem. This study presents strong, direct evidence for plant-soil interactions at an early stage of vascular plant radiation. Soil stabilization by complex rhizome systems was apparently widespread, and contributed to landscape modification at an earlier time than had been appreciated.National Natural Science Foundation of China [41272018]; Yunnan Key Laboratory for Palaeobiology, Yunnan University [2015DG007-KF04]; Key Laboratory of Economic Stratigraphy and Palaeogeography, Chinese Academy of Sciences (Nanjing Institute of Geology and Palaeontology)SCI(E)[email protected]
Diagnosis and management of glutaric aciduria type I – revised recommendations
Glutaric aciduria type I (synonym, glutaric acidemia type I) is a rare organic aciduria. Untreated patients characteristically develop dystonia during infancy resulting in a high morbidity and mortality. The neuropathological correlate is striatal injury which results from encephalopathic crises precipitated by infectious diseases, immunizations and surgery during a finite period of brain development, or develops insidiously without clinically apparent crises. Glutaric aciduria type I is caused by inherited deficiency of glutaryl-CoA dehydrogenase which is involved in the catabolic pathways of L-lysine, L-hydroxylysine and L-tryptophan. This defect gives rise to elevated glutaric acid, 3-hydroxyglutaric acid, glutaconic acid, and glutarylcarnitine which can be detected by gas chromatography/mass spectrometry (organic acids) or tandem mass spectrometry (acylcarnitines). Glutaric aciduria type I is included in the panel of diseases that are identified by expanded newborn screening in some countries. It has been shown that in the majority of neonatally diagnosed patients striatal injury can be prevented by combined metabolic treatment. Metabolic treatment that includes a low lysine diet, carnitine supplementation and intensified emergency treatment during acute episodes of intercurrent illness should be introduced and monitored by an experienced interdisciplinary team. However, initiation of treatment after the onset of symptoms is generally not effective in preventing permanent damage. Secondary dystonia is often difficult to treat, and the efficacy of available drugs cannot be predicted precisely in individual patients. The major aim of this revision is to re-evaluate the previous diagnostic and therapeutic recommendations for patients with this disease and incorporate new research findings into the guideline
A review of paleobotanical studies of the Early Eocene Okanagan (Okanogan) Highlands floras of British Columbia, Canada and Washington, USA.
The history of plant fossil collecting in the Okanagan (Okanogan) Highlands of British Columbia and northeastern Washington is closely intertwined with the history of geological surveys and mining activities from the 1870’s onward. The first descriptions of fossil plants from British Columbia were published in 1870–1920 by J.W. Dawson, G.M. Dawson and D.P. Penhallow. In the U.S.A., fossil leaves and fish were first recognized at Republic by miners in the early 1900's. Many early workers considered these floras to be of Oligocene or Miocene age. Arnold described Canadian occurrences of conifers and Azolla in the 1950’s. Palynological studies in the 1960’s by Hills, Rouse and others and those of fossil fish by Wilson in the 1970–80’s provided the framework for paleobotanical research at several key localities. Permineralized plants were first described from the Princeton chert in the 1970’s by Miller, Basinger and others, followed by Stockey and her students. Wehr and Johnson revitalized the study of fossils at Republic with the discovery of a diverse assemblage in 1977. In 1987 Wolfe and Wehr produced a USGS monograph on Republic and Wehr cofounded the Stonerose Interpretive Center as a venue for public collecting. Systematic studies of the Okanagan Highlands plants, as well as paleoecological and paleoclimate reconstructions from palynomorphs and leaf floras, continue to expand our understanding of this important Early Eocene assemblage.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
A new proposal concerning the botanical origin of Baltic amber
Baltic amber constitutes the largest known deposit of fossil plant resin and the richest repository of fossil insects of any age. Despite a remarkable legacy of archaeological, geochemical and palaeobiological investigation, the botanical origin of this exceptional resource remains controversial. Here, we use taxonomically explicit applications of solid-state Fourier-transform infrared (FTIR) microspectroscopy, coupled with multivariate clustering and palaeobotanical observations, to propose that conifers of the family Sciadopityaceae, closely allied to the sole extant representative, Sciadopitys verticillata, were involved in the genesis of Baltic amber. The fidelity of FTIR-based chemotaxonomic inferences is upheld by modern–fossil comparisons of resins from additional conifer families and genera (Cupressaceae: Metasequoia; Pinaceae: Pinus and Pseudolarix). Our conclusions challenge hypotheses advocating members of either of the families Araucariaceae or Pinaceae as the primary amber-producing trees and correlate favourably with the progressive demise of subtropical forest biomes from northern Europe as palaeotemperatures cooled following the Eocene climate optimum
Fossil dennstaedtiaceae and hymenophyllaceae from the early eocene of the pacific northwest
Premise of research. Newly recognized compression fossils of fertile leptosporangiate ferns assignable to Dennstaedtia Bernh. (Dennstaedtiaceae) and Hymenophyllum Sm. (Hymenophyllaceae) are described from the latest early Eocene floras of the Okanogan Highlands, British Columbia, Canada, and northeastern Washington. Methodology. Specimens were photographed with reflected light microscopy and were studied morphologically in comparison with related fossil and extant forms. Focus-shift stacking was used to layer photos of some specimens. Some were photographed with polarized light. The holotype specimen of Dennstaedtia christophelii sp. nov. was also studied with environmental scanning electron microscopy. Pivotal results. We describe D. christophelii sp. nov. (Dennstaedtiaceae) and Hymenophyllum axsmithii sp. nov. (Hymenophyllaceae) on the basis of vegetative and fertile remains of fragmentary fronds. Specimens of D. christophelii are one-pinnate-pinnatifid to bipinnate and bear frequent marginal round sori in cuplike indusia on small crenulate to dissected pinnae. Sporangia each have a prominent annulus with approximately six to eight long cells visible. Hymenophyllum axsmithii has the type of lamina cutting, sorus position, alate rachis, sorus shape, and venation corresponding to Hymenophyllum, subgenus Sphaerocionium (Hymenophyllaceae). The numerous sporangia per sori each bear a prominent annulus, and 7-10 casts of spores are noted in some sporangia. Conclusions. These fossils document the occurrence of leptosporangiate fern diversity in the early Eocene Okanogan Highlands floras. Dennstaedtia christophelii represents one of several occurrences of Dennstaedtiaceae in the Eocene. Hymenophyllum axsmithii is the first unequivocal member of Hymenophyllaceae to be reported from these diverse plant and insect assemblages from lacustrine and swamp settings under warm temperate climates of the latest early Eocene
Conifers are a major source of sedimentary leaf wax n-alkanes when dominant on the landscape: Case studies from the Paleogene
Paleobotanical site information, terpenoid, n-alkane, and other and biomarker quantification and carbon isotope data from sediment samples collected from North America Paleogene fossil leaf sites that extend from Colorado to the High Arctic. Sediment samples were collected laterally along fossil leaf-bearing zones. To disentangle the vegetation source of sediment n-alkanes, we measured the carbon isotope (δ13C) values of nonsteroidal triterpenoids (angiosperm biomarkers) and tricyclic diterpenoids (conifer biomarkers) to determine angiosperm and conifer end member δ13C values. Compounds were isolated using column chromatography and identified and quantified with an Agilent 7890A gas chromatograph (GC) interfaced to an Agilent 5975C quadrupole mass selective detector (MSD) and flame ionization detector (FID). Compound-specific carbon isotope analyses were performed, where possible, on n-C27 through n-C35 alkanes, diterpenoids, and triterpenoids by gas chromatograph-combustion-isotope ratio mass spectrometry (GC-C-IRMS)
Belowground Rhizomes in Paleosols: The Hidden Half of an Early Devonian Vascular Plant
The colonization of terrestrial environments by rooted vascular plants had far-reaching impacts on the Earth system. However, the belowground structures of early vascular plants are rarely documented, and thus the plant-soil interactions in early terrestrial ecosystems are poorly understood. Here we report the earliest rooted paleosols (fossil soils) in Asia from Early Devonian deposits of Yunnan, China. Plant traces are extensive within the soil and occur as complex network-like structures, which are interpreted as representing long-lived, belowground rhizomes of the basal lycopsid Drepanophycus. The rhizomes produced large clones and helped the plant survive frequent sediment burial in well-drained soils within a seasonal wet-dry climate zone. Rhizome networks contributed to the accumulation and pedogenesis of floodplain sediments and increased the soil stabilizing effects of early plants. Predating the appearance of trees with deep roots in the Middle Devonian, plant rhizomes have long functioned in the belowground soil ecosystem. This study presents strong, direct evidence for plant-soil interactions at an early stage of vascular plant radiation. Soil stabilization by complex rhizome systems was apparently widespread, and contributed to landscape modification at an earlier time than had been appreciated
Leaf wax n-alkane carbon isotope data from sediment samples collected from fossil leaf sites extending from New Mexico to the High Arctic
Site information and leaf wax n-alkane carbon isotope data from sediment samples collected from fossil leaf sites extending from New Mexico to the High Arctic and span 40 million years from the Late Cretaceous to the Oligocene