Stable-isotope paleoclimate records for southern Ontario, Canada: comparison of results from marl and wood

1988 ◽  
Vol 25 (9) ◽  
pp. 1397-1406 ◽  
Author(s):  
T. W. D. Edwards ◽  
P. Fritz
Keyword(s):  
Meteoric Water ◽  
Terrestrial Plants ◽  
Southern Ontario ◽  
Midwest United States ◽  
Water Composition ◽  
Dry Conditions ◽  
Evaporative Enrichment ◽  
Paleoclimate Records ◽  
Data Yield

Profiles of δ18O in two marl cores from southern Ontario, Canada, are compared in detail with the records of meteoric water isotopic composition and photosynthetic humidity obtained from previous isotopic studies using wood cellulose at Brampton, Ontario. By accounting for the inferred changes in meteoric water composition and temperature, the changes in the oxygen-isotope content of the marl arising from fluctuations in the evaporative enrichment of the lakewater can be estimated. The resulting synthetic profiles of relative evaporative enrichment from both marl cores exhibit strong correspondence to the photosynthetic humidity profile generated from the studies at Brampton, which substantiates the importance of evaporation in the water budgets of these two lakes. A striking analogy exists between the isotopic evaporative enrichment response of such lakewaters and that of the waters in terrestrial plants; both of the marl lakes approach close to isotopic steady state during the summer season, when carbonate precipitation occurs.The results of these studies strengthen the basis for paleoclimatic interpretations suggested in previous reports. Most notably, the marl data yield further evidence for relatively dry conditions in southern Ontario during the early part of the Hypsithermal interval, at a time that coincides with maximum eastward extension of prairie in the midwest United States.

SPROUTING AND DEVELOPMENT OF YELLOW NUT SEDGE TUBERS

1977 ◽  
Vol 57 (2) ◽  
pp. 509-514 ◽  
Author(s):  
G. H. FRIESEN ◽  
A. S. HAMILL
Keyword(s):  
Root Growth ◽  
Day Length ◽  
Tuber Initiation ◽  
Soil Types ◽  
Cyperus Esculentus ◽  
Southern Ontario ◽  
Tuber Production ◽  
Dry Conditions ◽  
Top 40 ◽  
Long Photoperiod

Tubers of yellow nut sedge (Cyperus esculentus L.) were collected from four farm fields representing three soil types in southern Ontario in November of 1974 or 1975. These fields contained from 760 to 8,484 tubers/m2 in the top 40 cm of soil. Tubers extracted from these soils failed to sprout following 6 wk of storage under dry conditions, but sprouting approached 100% if previously stored under cool, moist conditions. Cool temperatures during dry storage for 90 wk reduced subsequent sprouting. Tubers sprouted as well in the greenhouse as in petri plates in a germination chamber. Root growth averaged 2 cm/day in glass-lined root boxes and tuber initiation commenced 90 days after planting. Tuber production was greatest under a short day length of 12 h or less, while shoot and root growth was stimulated by a long photoperiod.

Terrestrial plants and marine algae from the Late Jurassic lithographic limestone of the Causse Méjean (Lozère, southern France)

2016 ◽  
Vol 187 (2) ◽  
pp. 121-127
Author(s):  
Jean-David Moreau ◽  
Louis Baret ◽  
Gérard Lafaurie ◽  
Carmela Chateau-Smith
Keyword(s):  
Late Jurassic ◽  
Marine Algae ◽  
Coastal Areas ◽  
Land Plants ◽  
Fossil Plants ◽  
Terrestrial Plants ◽  
Southern France ◽  
Lithographic Limestone ◽  
Dry Conditions ◽  
Marine Lagoon

Abstract A new Late Jurassic flora was discovered in the fossiliferous lithographic limestone of the Causse Méjean, Lozère (southern France). It consists of the first Kimmeridgian/Tithonian plants from this area. Fossil plants are represented by megaremains preserved as impressions. This flora shows a co-occurrence of terrestrial plants and marine algae. The land plants include vegetative remains ascribed to bennettitaleans (Zamites Brongniart, 1828), conifers (Brachyphyllum Brongniart, 1828), and pteridosperms (Cycadopteris Zigno, 1853). Marine algae were ascribed to dasyclads (Goniolina D’Orbigny, 1850). Lithological and palaeontological features suggest preservation in a flat, homogeneous, protected environment, perhaps a brackish or marine lagoon, influenced by both continental and marine inputs. This discovery complements the few existing reports of European Late Jurassic floras, and indicates that coastal habitats were dominated by sub-arborescent vegetation, consisting of bennettitaleans and pteridosperms, and arborescent plants, such as conifers. Both the palaeoenvironmental context and certain xerophytic features suggest that these terrestrial plants from the Causse Méjean were well adapted to the hot, dry conditions of coastal areas.

scholarly journals A Hydrostratigraphic Framework for the Paleozoic Bedrock of Southern Ontario

2021 ◽  
Vol 48 (1) ◽  
pp. 23-58
Author(s):  
Terry R. Carter ◽  
Lee D. Fortner ◽  
Hazen A.J. Russell ◽  
Mitchell E. Skuce ◽  
Fred J. Longstaffe ◽  
...  
Keyword(s):  
Water Regime ◽  
Meteoric Water ◽  
Shallow Groundwater ◽  
Surficial Sediments ◽  
Deep Subsurface ◽  
Southern Ontario ◽  
Intermediate Regime ◽  
Hydrogeological Characteristics ◽  
Lithostratigraphic Units ◽  
Groundwater Systems

Groundwater systems in the intermediate to deep subsurface of southern Ontario are poorly understood, despite their value for a number of societal uses. A regional hydrostratigraphic framework is a necessary precursor for improving our understanding of groundwater systems and enabling development of a 3-D hydrostratigraphic model to visualize these groundwater systems. This study is a compilation and integration of published and unpublished geological, hydrogeological, hydrochemical and isotopic data collected over the past 10 years to develop that framework.Bedrock is covered by a thin veneer of surficial sediments that comprise an aquifer/aquitard system of considerable local variability and complexity. Aquifers in the bedrock are thin and regionally extensive, separated by thick aquitards, within a well-defined lithostratigraphic framework and a well-developed hydrochemical depth zonation comprising a shallow fresh water regime, an intermediate brackish to saline sulphur water regime, and a deep brine regime of ancient, evaporated seawater. Occurrence and movement of groundwater in shallow bedrock is principally controlled by modern (Quaternary) karstic dissolution of subcropping carbonate and evaporite rocks, and in the intermediate to deep subsurface by paleokarst horizons developed during the Paleozoic. Flow directions in the surficial sediments of the shallow groundwater regime are down-gradient from topographic highs and down the regional dip of bedrock formations in the intermediate regime. Shallow karst is the entry point for groundwater penetration into the intermediate regime, with paleo-recharge by glacial meltwater and limited recent recharge by meteoric water at subcrop edges, and down-dip hydraulic gradients in confined aquifers. Hydraulic gradient is up-dip in the deep brine regime, at least for the Guelph Aquifer and the Cambrian Aquifer, with no isotopic or hydrochemical evidence of infiltration of meteoric water and no discharge to the surface.Fourteen bedrock hydrostratigraphic units are proposed, and one unit comprising all the surficial sediments. Assignment of lithostratigraphic units as hydrostratigraphic units is based principally on hydrogeological characteristics of Paleozoic bedrock formations in the intermediate to deep groundwater regimes, below the influence of modern meteoric water. Carbonate and evaporite rocks which form aquitards in the subsurface may form aquifers at or near the surface, due to karstic dissolution by acidic meteoric water, necessitating compromises in assignment of hydrostratigraphic units.

Integrating Stalagmite, Vertebrate, and Pollen Sequences to Investigate Holocene Vegetation and Climate Change in the Southern Midwestern United States

1999 ◽  
Vol 52 (3) ◽  
pp. 381-387 ◽  
Author(s):  
Rhawn F. Denniston ◽  
Luis A. Gonzalez ◽  
Holmes A. Semken ◽  
Yemane Asmerom ◽  
Richard G. Baker ◽  
...  
Keyword(s):  
Climate Change ◽  
Deciduous Forest ◽  
North Central ◽  
South Central ◽  
Dry Conditions ◽  
Oxygen Isotopic ◽  
Isotopic Records ◽  
Paleoclimate Records ◽  
Climate Proxies ◽  
Vegetation And Climate

Speleothem carbon and oxygen isotopic records from Onondaga Cave, south-central Missouri, and Beckham Creek Cave, north-central Arkansas, are compared with the Cupola Pond and Oldfield Swamp pollen series from southeastern Missouri and the Rodgers Shelter and Modoc Shelter vertebrate biostratigraphic sequences from central Missouri and southwestern Illinois. Similar, and roughly contemporaneous, shifts between deciduous forest and steppe indicators throughout the Holocene are revealed in each database. These independent proxies record steppe conditions between approximately 9000 and 1500 cal yr B.P. A shift toward lighter speleothem carbon may reflect a change from warm and dry to cool and dry conditions between 4500 and 3000 yr B.P. The sensitive response of speleothem δ13C to changes in vegetation emphasizes their importance as paleoclimate records in an area containing few other millenial-scale climate proxies.

scholarly journals Isotope and Geochemistry Characterization of Hot Springs and Cold Springs of Sembalun – Rinjani Area, East Lombok, West Nusa Tenggara – Indonesia

2020 ◽  
Vol 20 (6) ◽  
pp. 1347
Author(s):  
Satrio Satrio ◽  
Rasi Prasetio ◽  
Boy Yoseph Cahya Sunan Sakti Syah Alam ◽  
Teuku Yan Waliyana Muda Iskandarsyah ◽  
Faizal Muhammadsyah ◽  
...  
Keyword(s):  
Meteoric Water ◽  
Hot Springs ◽  
Hot Spring ◽  
Chloride Content ◽  
Gas Analysis ◽  
Subsurface Temperature ◽  
Water Composition ◽  
Reservoir Fluid ◽  
Geothermal Potential ◽  
Type Water

The presence of several hot springs in Sembalun – Rinjani, East Lombok, West Nusa Tenggara is an indicator of geothermal potential in the area. This study aims to determine the characteristics of hot springs and cold springs and also the geothermal potential in Sembalun – Rinjani area using isotopes and geochemistry methods. The result of d18O and d2H stable isotopes analysis shows that most of the hot springs are meteoric water. Except for Kalak hot spring, other hot springs are a mixing product of meteoric water and andesitic water, with meteoric water composition between 64 to 87%. While 14C radioisotope suggests that the age of hot springs in the Sembalun area is about 10,000–12,000 years BP, the surrounding cold springs are mostly Modern except Jorong cold spring. The results of gas analysis (He, Ar, and Ne) also suggest the same origin of geothermal fluid, i.e., meteoric water origin. Based on chemical composition, Kalak hot spring is plotted as sulfate type water, while Sebau hot spring is plotted near mature water composition but not representing reservoir fluid due to its relatively low temperature and high Mg content. Na/K geothermometer calculation from Sembalun area shows that subsurface temperature is varied between 111-161 °C, while from Rinjani hot springs indicates higher subsurface temperature, i.e., 250-260 °C. It is estimated that reservoir fluid has high TDS with chloride content up to 4000 mg/L.

Studies on Anopheles gambiae Giles and malaria transmission in the Umbugwe area of Tanganyika

1964 ◽  
Vol 55 (1) ◽  
pp. 125-137 ◽  
Author(s):  
A. Smith
Keyword(s):  
Anopheles Gambiae ◽  
Malaria Transmission ◽  
Seasonal Transmission ◽  
Large Numbers ◽  
Larval Survey ◽  
Type Form ◽  
Dry Conditions ◽  
The Government ◽  
Anopheles Gambiae Giles

The paper includes a description of studies on Anopheles gambiae Giles in the insecticide-free Umbugwe area of Tanganyika, and the results of dissections of A. gambiae and A. funestus Giles for sporozoite infections.The densities of A. gambiae and A. funestus were assessed in houses by pyrethrum spray catches in 90 houses distributed in ten villages in the Umbugwe area between March 1960 and February 1962. A. gambiae was seasonally abundant, a sharp increase in density being associated with periods of rain. A. funestus type form was scarce in houses throughout the year, although a larval survey showed it to be the most common member of the complex of A. funestus in the area.The average ratio of fed to gravid individuals of A. gambiae was 2·3:1 from June 1960 to November 1961, with peaks reaching 7:1 in March 1960 and 7·5:1 in January 1962. The peaks were attributed to rapid increase in production of adults during the limited period of the rainy seasons that followed very dry conditions.Thirteen per cent, of recently fed individuals of A. gambiae were found in the exit window traps of experimental huts, having attempted to leave the huts on the night of feeding.Two distinct types of huts are commonly found in the area, the tembe, which is large, divided into an average of five rooms by walls that are usually incomplete at the top, and accommodates large numbers of cattle as well as humans; and the banda, which is smaller, divided only into two rooms and seldom housing any domestic animals. Precipitin tests showed that whereas only 20 per cent, of individuals of A. gambiae taken in tembe had fed on man, in banda huts the percentage was 77. It was also shown that there was a dispersal of A. gambiae within a hut shortly after feeding. In a tembe. one-third of the individuals positive for man, and one-quarter of those positive for cattle had moved to rooms other than those in which they had fed.A sporozoite rate of 1·47 per cent, was found among 3,746 specimens of A. gambiae dissected. Of the total number of 55 sporozoite-positive females of A. gambiae, 39 were found among the 424 individuals dissected in February 1962, thereby indicating unusually heavy transmission during the early part of 1962. A. funestus type form appeared to be of virtually no importance in malaria transmission in the Umbugwe area. Transmission by A. gambiae was highly seasonal, for although the percentage of gland-positive specimens was slightly higher in the long dry season than in the rainy season, the much larger mosquito population in the latter led to a higher number of infective bites in the rainy seasons. The highly seasonal transmission by A. gambiae was reflected in the results of examination of blood-films of people attending the Government dispensary.

scholarly journals Hydrogeology and origin of waters of the Panyam Volcanic Line springs, Jos Plateau, Nigeria

2021 ◽  
Vol 43 (2) ◽  
Author(s):  
Longpia C. B.
Keyword(s):  
Stable Isotope ◽  
Meteoric Water ◽  
Ph Value ◽  
Isotope Composition ◽  
Water Type ◽  
Water Composition ◽  
Piper Trilinear Diagram ◽  
Physico Chemical ◽  
Isotope Ratio Mass Spectrometer ◽  
Irrigation Quality

The PVL springs are used for both domestic and agricultural purposes. The seepage from the springs has resulted in producing a large expanse of wetlands and is therefore intensively use for dry season farming. The aim of this study was to determine the hydrogeological, hydrochemical characteristics, origin and their suitability for domestic and irrigation. The hydrogeology of the springs was determined by field mapping. The physico-chemical parameters were determined in the field and by laboratory methods. For the cation and anion analysis the ICP-MS and the wet methods were employed respectively. The stable isotope composition of oxygen (δ18O) and hydrogen (δ2H) were analyzed by Isotope Ratio Mass Spectrometer. The hydrochemical analysis revealed that the PVL springs waters are generally neutral with an average pH value of 7.3. The average TDS and EC values are 127.8mg/l and 246µs/cm respectively. These values fall within fresh water class. The average Mg2+,Ca2+, Na+ and K+ cation concentration values are 16.3mg/l, 15.8mg/l, 10.8mg/l and 5.58mg/l respectively. The average anions concentration of HCO3-, SO4 and Cl- are 140mg/l, 8.6mg/l and 3.4mg/l respectively. Piper trilinear diagram show that the spring waters is predominantly Mg-Ca-HCO3 water type with potable qualities based on WHO drinking water standards. The sodium Adsorption Ratio (SAR) and Sodium Soluble Percentage (SSP) values range between 0.44 to 0.84 and 26.4 to 54% respectively and falls within irrigation quality standards. Stable isotope compositions of δ18O and δ2H ranges from -3.60/00 to -4.90/00 and -200/00 to -280/00 respectively falls within the meteoric water composition. This is further affirmed by the δ2H versus δ18O plot on the correlation diagram with Standard Meteoric Water Line.

Clay mineral authigenesis along a mid-continental scale fluid conduit in Palaeozoic sedimentary rocks from southern Ontario, Canada

Clay Minerals ◽  
2000 ◽  
Vol 35 (1) ◽  
pp. 239-260 ◽  
Author(s):  
K. Ziegler ◽  
F. J. Longstaffe
Keyword(s):  
Meteoric Water ◽  
Isotope Composition ◽  
Sedimentary Basins ◽  
Southern Ontario ◽  
Continental Scale ◽  
Brine Migration ◽  
Stable Isotopic ◽  
Taconic Orogeny ◽  
O Isotope ◽  
Appalachian Foreland

AbstractRocks above and below the Precambrian-Palaeozoic unconformity at the base of many Palaeozoic sedimentary basins of mid-continental North America are distinguished by secondary K-feldspar, chlorite and illite. Thrusting of the Appalachian foreland is generally considered responsible for the fluid migrations which caused this alteration. We have examined secondary chlorite and illite from Cambro-Ordovician rocks which overlie the unconformity in southern Ontario, Canada. This area is situated along the interface between the Michigan and Appalachian basins. Water involved in chloritic alteration at ~150°C has an O isotope composition compatible with a basinal brine evolved from seawater. Brine migration was probably triggered by the Taconic Orogeny to the east. In comparison, the secondary illite (365–321 Ma) largely postdates the Acadian Orogeny, and the illite-forming fluids have stable isotopic compositions typical of tepid (~40–55°C) meteoric water. We suggest that basement arches beneath southern Ontario were reactivated by this orogeny, which facilitated introduction of meteoric water. Similar alteration in underlying Precambrian rocks shows that fluid flow was focused along the unconformity during the regional Ordovician brine migration, as well as during the localized Mississippian introduction of fresh water.

Anatomical aspects of xeromorphy in arid-adapted plants of Australia

2020 ◽  
Vol 68 (3) ◽  
pp. 245 ◽  
Author(s):  
V. M. Dörken ◽  
P. G. Ladd ◽  
R. F. Parsons
Keyword(s):  
Close Association ◽  
Arid Environments ◽  
Arid Areas ◽  
Tissue Formation ◽  
Terrestrial Plants ◽  
Shrub Species ◽  
Structural Support ◽  
Dry Conditions ◽  
Broad Leaved Species ◽  
Sclerophyllous Plants

Plants from arid environments have some of the most diverse morphological and anatomical modifications of any terrestrial plants. Most perennials are classified as xerophytes, and have structures that limit water loss during dry weather, provide structural support to help prevent cell collapse during dry periods or store water in photosynthetic tissues. Some of these traits are also found in sclerophyllous plants and traits that may have developed due to evolution of taxa on nutrient poor soils may also benefit the plants under arid conditions. We examined the morpho-anatomical features of photosynthetic organs of three tree and four shrub species with reduced leaves or photosynthetic stems that occur in arid or semiarid sites in Australia to see if there were patterns of tissue formation particularly associated with xeromorphy. In addition, we reviewed information on succulent and resurrection species. In the tree species (Callitris spp.) with decurrent leaves clothing the stems, the close association between the water transport system and stomata, along with anisotropic physiology would allow the species to fix carbon under increasingly dry conditions in contrast to more broad-leaved species. The shrub species (Tetratheca species and Glischrocaryon flavescens) with photosynthetic stems had extensive sclerenchyma and very dense chlorenchyma. The lack of major anatomical differences between leafless species of Tetratheca from arid areas compared with more mesic sites indicates that quite extreme morphological modifications may not exclude species from growing successfully in competition with species from less arid areas. The sclerophyll flora now characteristic of Australian vegetation from seasonally arid climates may have evolved during mesic times in the past but with relatively minor modifications was able to adjust to the gradually drying climate of much of Australia up to the present time.

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