Postglacial vegetational change and soil development in southeastern Labrador as inferred from pollen and chemical stratigraphy

1985 ◽  
Vol 63 (3) ◽  
pp. 543-561 ◽  
Author(s):  
D. R. Engstrom ◽  
B. C. S. Hansen
Keyword(s):  
Lake Sediments ◽  
Picea Glauca ◽  
Abies Balsamea ◽  
Organometallic Complexes ◽  
Soil Weathering ◽  
Vegetational Change ◽  
Humic Materials ◽  
High Concentrations ◽  
Humus Accumulation ◽  
Geochemical Analyses

Palynological and geochemical analyses of Holocene lake sediments are used to evaluate long-term interactions between vegetation and soils from four sites in southeastern Labrador, Canada. Changes in soil composition are inferred from the stratigraphy of humic materials and the elemental composition of authigenic and allogenic fractions of the sediment. Early Holocene lake muds deposited under tundra vegetation are predominantly inorganic and contain high concentrations of allogenic elastics derived from the erosion of barren soils. Concentrations of humic materials and redox–pH-sensitive elements (Fe, Mn, P, Al) of authigenic origin increase markedly with the subsequent invasion of spruce and fir (8000–7000 years BP). These changes represent decreased erosion of clastic minerals and increased mobilization of organometallic complexes from waterlogged soils produced through humus accumulation under coniferous vegetation. This transition of inorganic tundra inceptisols to humic-rich boreal spodosols contributed to the competitive replacement of Picea glauca and Abies balsamea by the more edaphically tolerant P. mariana between 6500 and 6000 years BP. A subsequent decline in sedimentary humic content and increase in allogenic components may signal a regional climatic cooling after 4000 years BP. Geochemical analyses of lake sediments reveal no stratigraphic changes in allogenic mineral composition that might indicate progressive soil weathering.

scholarly journals Gold-Bearing Brown Coal Deposits of the Zeya–Bureya Sedimentary Basin (East Russia): Fundamental Model of Formation

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 682
Author(s):  
Anatoliy Petrovich Sorokin ◽  
Andrey Alexeyevich Konyushok ◽  
Valeriy Mikhailovich Kuz’minykh ◽  
Sergey Vadimovich Dugin
Keyword(s):  
Sedimentary Basin ◽  
Complex Compounds ◽  
Inorganic Materials ◽  
Primary Sources ◽  
East Russia ◽  
High Concentrations ◽  
Geochemical Analyses ◽  
Element Transfer ◽  
Bureya Sedimentary Basin ◽  
Gold Bearing

The primary sources and the conditions for the formation of the Paleogene–Neogene coal-bearing deposits in the Zeya–Bureya sedimentary basin were identified and studied with the help of paleogeographic reconstructions and geochemical analyses. Based on the results obtained, we suggest a new basic model of element transfer into the coal, involving two mutually complementary processes to account for the introduction and concentration of gold and other trace elements in the sequences investigated. The first process reflects the system in which peatlands were concentrated along the basin’s junction zone and the passive internal residual mountain ranges. The second reflects the junction’s contrast-type (sharp-type) forms conditions along the external mobile mountain-fold frame. The eroded gold particles were transported over 10–20 km as complex compounds, colloids, dispersed particles, and nanoparticles, and remobilized into clastogenic and dissolved forms along the first few kilometers. The release of gold in the primary sources occurred due to weathering of gold-bearing ore zones, followed by transportation of gold by minor rivers to the areas of peat accumulation. This study considered the probability of the accumulation of high concentrations of gold and rare earth elements (REE) in coal due to the introduction of organic and inorganic materials during floods, with episodes of catastrophic events, and volcano–hydrothermal activities.

Hydrochemistry and carbonate sediment characterisation of Bacalar Lagoon, Mexican Caribbean

2019 ◽  
Vol 70 (3) ◽  
pp. 382 ◽  
Author(s):  
Nidia I. Tobón Velázquez ◽  
Mario Rebolledo Vieyra ◽  
Adina Paytan ◽  
Kyle H. Broach ◽  
Laura M. Hernández Terrones
Keyword(s):  
Trace Elements ◽  
Water Column ◽  
Saturation Index ◽  
Major Elements ◽  
Anthropogenic Sources ◽  
Pollution Indices ◽  
Mexican Caribbean ◽  
High Concentrations ◽  
Geochemical Analyses ◽  
Changes Over Time

The aim of the study is to determine the distribution of trace and major elements in the water and in the sediments of the south part of the Bacalar Lagoon and to identify the sources of the trace elements and their changes over time. The western part of the lagoon water column is characterised by high concentrations of Ca2+, HCO3– and Sr2+, derived from groundwater input. In contrast, the eastern part of the lagoon is characterised by high concentrations of Mg2+, Na+ and Cl–. The lagoon is not affected by present-day seawater intrusion. Water column and sediment geochemical analyses performed in Bacalar Lagoon show clear spatial distribution of different parameters. The saturation index of the water column indicates three main groups: (1) a zone oversaturated with regard to aragonite, calcite and dolomite; (2) an undersaturated area where all three minerals are dissolving; and (3) an area with calcite equilibrium and undersaturation with regard to the other minerals. Herein we present the first measurements of trace element (Ba2+, Mn2+, K+, Ni2+, Zn2+) concentrations in carbonates obtained from sediments in Bacalar Lagoon. In order to evaluate whether the trace elements are derived from natural or anthropogenic sources, four pollution indices were calculated. The results confirmed that Bacalar Lagoon sediments are not contaminated with Ni2+, K+, Mn2+ and Ba2+, and that the Zn2+ seems to have a predominantly anthropogenic origin.

Short-term effects of cut-to-length versus full-tree harvesting on conifer regeneration in jack pine, mixedwood, and black spruce forests in Manitoba

2004 ◽  
Vol 34 (9) ◽  
pp. 1938-1945 ◽  
Author(s):  
Isobel Waters ◽  
Steven W Kembel ◽  
Jean-François Gingras ◽  
Jennifer M Shay
Keyword(s):  
Picea Mariana ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
Black Spruce ◽  
Abies Balsamea ◽  
Jack Pine ◽  
Tree Regeneration ◽  
Understorey Vegetation ◽  
Advance Regeneration ◽  
The Impact

This study compares the effects of full-tree versus cut-to-length forest harvesting methods on tree regeneration in jack pine (Pinus banksiana Lamb.), mixedwood (Picea glauca (Moench) Voss – Populus tremuloides Michx. – Abies balsamea (L.) Mill.), and black spruce (Picea mariana (Mill.) BSP) sites in southeastern Manitoba, Canada. We surveyed tree regeneration densities, disturbance characteristics, and understorey vegetation in replicated control and harvested plots in each site type preharvest (1993) and 1 and 3 years postharvest (1994, 1996). In jack pine sites, the full-tree harvest method promoted regeneration of Pinus banksiana through increased disturbance of soil and the moss layer, and decreased slash deposition relative to the cut-to-length method. Conversely, in mixedwood sites the cut-to-length method resulted in less damage to advance regeneration and proved better at promoting postharvest regeneration of Abies balsamea and Picea glauca relative to the full-tree method. In black spruce sites, there were few differences in the impact of the two harvesting methods on regeneration of Picea mariana, which increased in frequency and density after both types of harvesting.

Development of an improved model estimating the nutrient content of the bole for four boreal tree species

1998 ◽  
Vol 28 (1) ◽  
pp. 37-43 ◽  
Author(s):  
P Rochon ◽  
D Paré ◽  
C Messier
Keyword(s):  
Populus Tremuloides ◽  
Tree Species ◽  
Picea Glauca ◽  
Nonlinear Models ◽  
Abies Balsamea ◽  
Nutrient Content ◽  
Forest Harvesting ◽  
Nutrient Concentrations ◽  
Nutrient Contents ◽  
Improved Model

An improved model for estimating nutrient contents of the commercial portion of tree boles was developed for four boreal tree species (Populus tremuloides Michx., Betula papyrifera Marsh., Picea glauca (Moench) Voss, and Abies balsamea (L.) Mill.). This model considers the spatial pattern of variation of nutrient concentrations inside the bole and its relationships with tree size. For all species-nutrient combinations, no significant pattern was found for vertical variations in nutrient concentrations, while two types of nonlinear models, using distance from the tree periphery as the independent variable, fit the pattern of horizontal (or radial) variations. These patterns of variability were used to estimate the global nutrient concentration of the bole by using mathematical integration. The values obtained with this method were generally lower, especially for large stems, than values obtained with traditional methods that do not consider the variability of nutrient concentrations inside the bole. This improved model would permit better estimates of the amounts of nutrients lost in biomass upon forest harvesting, as well as internal cycling of nutrients within the bole.

Tree macrofossils of Younger Dryas age from Cohoes, New York State, USA

2012 ◽  
Vol 49 (5) ◽  
pp. 671-680 ◽  
Author(s):  
Norton G. Miller ◽  
Carol B. Griggs
Keyword(s):  
New York ◽  
Picea Glauca ◽  
New York State ◽  
Abies Balsamea ◽  
Younger Dryas ◽  
Hudson River ◽  
Growth Responses ◽  
Radiocarbon Dates ◽  
Plant Remains ◽  
American Beaver

Tree macrofossils dating from the middle to end (about 1000 years, ca. 12 600–11 600 cal years BP) of the Younger Dryas chronozone were found in an organic deposit on the southwest side of the Mohawk River, near its junction with the Hudson River in Cohoes, New York, USA. The fossils included substantial wood fragments, associated plant remains, and pollen, which indicate a forest of white spruce ( Picea glauca ), balsam fir ( Abies balsamea ), and tamarack ( Larix laricina ). The presence of white, rather than black ( P. mariana ) or red ( P. rubens ) spruce in the Younger Dryas was probably due to a riparian-type environment, confirmed by its location and American beaver tooth marks on some of the wood fragments. The clusters of wood radiocarbon dates indicate periodic changes in erosion and deposition at the site. One possible but very short decline (temperature reversal?) may be indicated by tree-ring growth, but in general, the ring widths of the trees and their growth responses suggest variable but slowly improving conditions over time, possibly from warming temperatures, before the end of the Younger Dryas.

Morphological indicators of growth response of coniferous advance regeneration to overstorey removal in the boreal forest

2000 ◽  
Vol 76 (4) ◽  
pp. 633-642 ◽  
Author(s):  
Jean-Claude Ruel ◽  
Christian Messier ◽  
Yves Claveau ◽  
René Doucet ◽  
Phil Comeau
Keyword(s):  
Picea Glauca ◽  
Pinus Banksiana ◽  
Pinus Contorta ◽  
Sudden Change ◽  
Abies Balsamea ◽  
Critical Threshold ◽  
Species Number ◽  
Advance Regeneration ◽  
Tolerant Species ◽  
Shade Tolerant Species

Regeneration of forest stands through the preservation of existing advance regeneration has gained considerable interest in various regions of North America. The effectiveness of this approach relies on the capacity of regeneration to respond positively to overstory removal. Responses of advance regeneration to release is dependent on tree characteristics and site conditions interacting with the degree of physiological shock caused by the sudden change in environmental conditions. This paper presents a review of the literature describing the relationships between morphological indicators and the advance regeneration response to canopy removal. It focuses primarily on the following species: jack pine (Pinus banksiana Lamb.), lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.), black spruce (Picea mariana (Mill.) B.S.P.), interior spruce (Picea glauca × engelmannii), white spruce (Picea glauca (Moench) Voss), balsam fir (Abies balsamea (L.) Mill.), and subalpine fir (Abies lasiocarpa (Hook.) Nutt). Pre-release height growth has been found to be a good indicator of post-release response for many species. Live-crown ratio also appears to be a good indicator of vigour for shade-tolerant species. The ratio of leader length to length of the longest lateral at the last whorl could serve to describe the degree of suppression before harvest for shade-tolerant species. Number of nodal and internodal branches or buds has been found to be related with vigour for many species. Logging damage has been shown to be an important determinant of seedling response to overstory removal. In contrast, height/diameter ratio has limited value for predicting response to release since it varies with site, species and other factors. No clear relationship between age, height at release and response to release could be demonstrated. This paper also suggests the use of combined indicators and critical threshold values for these indicators. Key words: advance regeneration, careful logging, vigour, clearcutting

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