Geochemical factors controlling the accumulation and dispersal of heavy metals in the Bay of Fundy sediments

1982 ◽  
Vol 19 (5) ◽  
pp. 930-944 ◽  
Author(s):  
D. H. Loring
Keyword(s):  
Source Rocks ◽  
Bay Of Fundy ◽  
Fine Grained ◽  
Anthropogenic Inputs ◽  
Geochemical Factors ◽  
Industrial Sources ◽  
High Concentrations ◽  
Abundance And Distribution ◽  
Local Anomalies ◽  
Nova Scotian

Total Zn, Cu, Pb, Co, Ni, Cr, V, Hg, Be, As, Ba, and Se concentrations vary regionally and in response to textural variations of the sediments of the Bay of Fundy. They are, except for local anomalies, at or near natural levels in relation to their source rocks and other unpolluted marine sediments.Chemical partition indicates that small but significant amounts (1–27%) of the total element concentrations are potentially available to the biota. Potential bioavailable metals are derived from natural and industrial sources and are held in the sediments by fine grained organic material (Hg, Pb), hydrous iron oxides (Cr, V, Co, Pb), ion exchange positions (Zn), and calcareous components (Cu, Zn, Ba).Of the total metal content, however, 73–99% is not readily available to the biota but held in various sulphide (Zn, Cu, Pb, As, Se), oxide (Cr, Ni, Co, V), and silicate minerals (Cr, V, Co, Ni). The host minerals have accumulated at the same rates as other detrital material except for particles of zinc oxide that have been derived from industrial sources adjacent to the Bay of Fundy. The accumulations of fine grained host minerals are the main control on the abundance and distribution of Hg, Be, Zn, Pb, and As in the sediments whereas the dispersal of the ferromagnesian silicates and various oxide minerals, rather than the grain size of their hosts, accounts for dispersal of Cr, V, Co, and Ni in the sediments. These factors together with the present depositional pattern of the particles account for the accumulation and relative enrichment of most metals along with other fine grained materials in the "Quoddy region" of the bay. Local anomalies of detrital minerals related to bedrock exposures also account for high concentrations of Cr, V, and Ni in the vicinity of Grand Manan Island and along the Nova Scotian coast. Relatively high metal concentrations also occur near a dredge dispersal site off St. John Harbour and may reflect the initial impact of anthropogenic inputs on the natural levels of metals in the Fundy sediments.

Geochemistry of cobalt, nickel, chromium, and vanadium in the sediments of the estuary and open Gulf of St. Lawrence

1979 ◽  
Vol 16 (6) ◽  
pp. 1196-1209 ◽  
Author(s):  
D. H. Loring
Keyword(s):  
Mineral Deposit ◽  
Source Rocks ◽  
Anthropogenic Sources ◽  
Terrestrial Organic Matter ◽  
Lawrence Estuary ◽  
Fine Grained ◽  
Hydrous Oxides ◽  
High Concentrations ◽  
St Lawrence Estuary ◽  
Local Anomalies

Total Co (3–22 ppm), Ni (4–160 ppm), V (4–168 ppm), and Cr (8–241 ppm) concentrations vary regionally and with textural differences in the sediments of the St. Lawrence estuary and Gulf of St. Lawrence. They are, except for local anomalies, at or near natural levels relative to their source rocks and other marine sediments.Chemical partition and mineralogical analyses indicate that small but biochemically significant quantities (2–24%) of the total element concentrations are potentially available to the biota and are most likely held by fine-grained organic material, hydrous iron oxides, and ion exchange positions in the sediments. In the upper estuary, nondetrital Ni, Cr, and V supplied from natural and anthropogenic (Cr) sources are apparently preferentially scavenged from solution by terrestrial organic matter and hydrous oxides and concentrated in fine-grained sediments deposited below the turbidity maximum. In the lower estuary, the fine-grained sediments are relatively enriched in nondetrital V supplied from anthropogenic sources in the Saguenay system. Elsewhere the sedimentation intensities of the nondetrital elemental contributions have remained relatively constant with fluctuations in total sediment intensity.Seventy-six to 98% of the total Co, Ni, Cr, and V is not, however, available to the biota, but held in various sulphide, oxide, and silicate minerals. The host minerals have accumulated at the same rate as other fine-grained detrital material except for some local anomalies. In the upper estuary, detrital V concentrations are highest in the sands as an apparent result of an enrichment of ilmenite and titaniferous magnetite from a nearby mineral deposit. In the open gulf, relatively high concentrations of Ni, Cr, and V occur in sediments from the Bay of Islands, Newfoundland, and probably result from the seaward dispersal of detrital Ni, Cr, and V bearing minerals from nearby ultrabasic rocks.

scholarly journals Terciérní říční sedimenty v širším okolí Jihlavy

2019 ◽  
Vol 26 (1-2) ◽  
Author(s):  
Michal Francírek ◽  
Slavomír Nehyba
Keyword(s):  
Facies Analysis ◽  
River System ◽  
Flood Plain ◽  
Depositional Environments ◽  
Source Rocks ◽  
Oxbow Lake ◽  
Fine Grained ◽  
High Concentrations ◽  
Moldanubian Unit ◽  
Organic Deposits

Tertiary deposits have been known around Jihlava city for many years. However, they have never been thoroughly studied. Most of the known occurrences are situated in the Jihlava Furrow. During the drilling research, these Tertiary deposits were newly detected in three wells: HGM-1, V1 and V4. Facies analysis, petrography and gamma spectrometry were performed on samples taken from all three wells. The model of basement of Cenozoic deposits has been constructed. Based on facies analysis, 8 lithofacies (7 studied deposits and 1 eluvium) have been described. The study of lithofacies has made the recognition of the depositional environments of the Tertiary deposits possible. The depositional environments of these deposits are interpreted as fluvial channelized gravels and non-channelized deposits (flood plain, crevasse splays, oxbow lake and lake). The channelized gravels have been found by the well HGM-1 in the overburden of the crystalline rocks of the Moldanubian. Their thickness is relatively low (1.7 m) and the channels were probably not deep. The non-channelized deposits are formed by clays, silts and fine-grained sands. In the upper part of the succession a layer of organic deposits (peat) has been detected. The results of petrography have shown that material originated from local sources, especially Moldanubian Unit and Jihlava Massif (gneisses, mica-schistes, granitoids, less importantly pegmatites and phyllites). High concentrations of Th and U have been found in the studied deposits. These high concentrations can be associated with the source rocks. The values of Th /U and Th /K ratios are signifi cantly higher in the studied deposits than in eluvium. This indicates conditions of weathering and sedimentation, and also points to input of the material from several sources. The model of crystalline basement shows that there were probably at least two spatially separated fluvial river systems. One river system was situated in the area of Velký Beranov and Měšín. The preserved remains of the second system are visible in the area of Jihlava city and its peripheral parts (Bedřichov and Pávov).

Trace-metal geochemistry of sediments from Baffin Bay

1984 ◽  
Vol 21 (12) ◽  
pp. 1368-1378 ◽  
Author(s):  
D. H. Loring
Keyword(s):  
Heavy Metal ◽  
Trace Metal ◽  
Source Rocks ◽  
The Arctic ◽  
Weakly Bound ◽  
Metal Concentrations ◽  
Baffin Bay ◽  
Heavy Metal Concentrations ◽  
Fine Grained ◽  
Abundance And Distribution

The major- (Si, Al, Ti, Fe, Mn, Ca, Mg) and trace-metal (Zn, Cu, Pb, Co, Ni, Cr, V, Li, Cd, Hg) compositions of surficial sediments from Baffin Bay and the sounds (Lancaster, Jones, Smith) leading into the Arctic Ocean have been determined. The sediment composition varies regionally and in response to textural variations and the heavy-metal concentrations are at or near natural levels in relation to their source rocks and other uncontaminated shelf and oceanic sediments.Chemical partition indicates that most of the heavy-metal concentrations (80–99%) except for Cd (27–71%) are derived from various sulphide, oxide, and silicate minerals. The host minerals are predominantly fine grained and have accumulated at the same rate as other detrital clastic material of comparable grain size. As a result, the highest trace-metal concentrations occur in the fine-grained sediments occupying the deepest parts of the sounds and Baffin Bay. Although most of the metals have reached their depositional site by water transport, a small but significant amount has probably been ice rafted to the offshore areas, especially in the northern part of the bay. Only small amounts of the total metal concentrations (1–20%) except Cd (29–73%) are present in the nondetrital fraction. Although difficult to locate exactly, the metals in this fraction appear to reside in ion-exchange positions and in amorphous iron grain coatings and are weakly bound to fine-grained organic matter.Overall, the physical–chemical sedimentological conditions including ice movements are responsible for the dispersal and deposition of fine-grained inorganic and organic matter and for the control of the abundance and distribution of trace metals in this part of the eastern Canadian Arctic.

Emissions of porewater compounds and gases from the subaquatic sediment disposal site “rodewischhafen”, hamburg harbour

1998 ◽  
Vol 37 (6-7) ◽  
pp. 87-93 ◽  
Author(s):  
M. Kussmaul ◽  
A. Groengroeft ◽  
H. Koethe
Keyword(s):  
Water Surface ◽  
Disposal Site ◽  
Dredged Material ◽  
Water Fluxes ◽  
Gas Emissions ◽  
Fine Grained ◽  
Deposit Surface ◽  
Groundwater Samples ◽  
High Concentrations ◽  
Mud Deposit

In the year 1993 a confined and unused harbour basin was used to store 290,000 m3 of fine-grained dredged material from Hamburg harbour. About 70% of the deposit surface was water covered. The edge areas were above the water table and covered with reed. Emissions of dissolved compounds into the groundwater, as well as surface gas emissions were measured from 1994 to 1996. As indicators for water fluxes from the deposit we used NH4+ and HCO3− because of their high concentrations in mud porewater in comparison to groundwater. The average concentrations of NH4+ and HCO3− in the porewater increased during 2 years from 85 to 250 mg NH4+ 1−1 and from 2.0 to 3.1 g HCO3− 1−1, while the groundwater samples showed constant values of 8 mg NH4+ 1−1 and 0.7 g HCO3− 1−1. Furthermore, the average gas emissions over the water surface were 3.2 g CH4 m−2 d−1 and 0.8 g CO2 m−2 d−1. In contrast, no methane and 3.0 g CO2 m−2 d−1 were emitted from land areas. The results indicated, that there were no significant emissions of mud porewater compounds into the groundwater but high CH4-emissions over the water covered surface of the mud deposit.

scholarly journals The influences of sedimentary environments on organic matter enrichment in fine-grained rocks of the Paleogene Shahejie formation in Nanpu Sag, Huanghua Depression, Bohai Bay Basin

2021 ◽  
pp. 014459872110310
Author(s):  
Min Li ◽  
Xiongqi Pang ◽  
Guoyong Liu ◽  
Di Chen ◽  
Lingjian Meng ◽  
...  
Keyword(s):  
Organic Matter ◽  
Source Rocks ◽  
Bohai Bay ◽  
Bohai Bay Basin ◽  
Humid Climate ◽  
High Productivity ◽  
Fine Grained ◽  
Huanghua Depression ◽  
Shahejie Formation ◽  
Nanpu Sag

The fine-grained rocks in the Paleogene Shahejie Formation in Nanpu Sag, Huanghua Depression, Bohai Bay Basin, are extremely important source rocks. These Paleogene rocks are mainly subdivided into organic-rich black shale and gray mudstone. The average total organic carbon contents of the shale and mudstone are 11.5 wt.% and 8.4 wt.%, respectively. The average hydrocarbon (HC)-generating potentials (which is equal to the sum of free hydrocarbons (S1) and potential hydrocarbons (S2)) of the shale and mudstone are 39.3 mg HC/g rock and 28.5 mg HC/g rock, respectively, with mean vitrinite reflectance values of 0.82% and 0.81%, respectively. The higher abundance of organic matter in the shale than in the mudstone is due mainly to paleoenvironmental differences. The chemical index of alteration values and Na/Al ratios reveal a warm and humid climate during shale deposition and a cold and dry climate during mudstone deposition. The biologically derived Ba and Ba/Al ratios indicate high productivity in both the shale and mudstone, with relatively low productivity in the shale. The shale formed in fresh to brackish water, whereas the mudstone was deposited in fresh water, with the former having a higher salinity. Compared with the shale, the mudstone underwent higher detrital input, exhibiting higher Si/Al and Ti/Al ratios. Shale deposition was more dysoxic than mudstone deposition. The organic matter enrichment of the shale sediments was controlled mainly by reducing conditions followed by moderate-to-high productivity, which was promoted by a warm and humid climate and salinity stratification. The organic matter enrichment of the mudstone was less than that of the shale and was controlled by relatively oxic conditions.

Erosion and deposition of fine-grained sediments from the Bay of Fundy

Sedimentology ◽  
1985 ◽  
Vol 32 (6) ◽  
pp. 815-832 ◽  
Author(s):  
CARL L. AMOS ◽  
DAVID C. MOSHER
Keyword(s):  
Bay Of Fundy ◽  
Erosion And Deposition ◽  
Fine Grained

The Witwatersrand pyrites and metamorphism

1983 ◽  
Vol 47 (345) ◽  
pp. 473-479 ◽  
Author(s):  
D. K. Hallbauer ◽  
K. von Gehlen
Keyword(s):  
Trace Element ◽  
Fluid Inclusions ◽  
Depositional Environment ◽  
Volcanic Rocks ◽  
Source Rocks ◽  
Fine Grained ◽  
Mineral Inclusions ◽  
Ore Minerals ◽  
Hand Specimen

AbstractEvidence obtained from morphological and extensive trace element studies, and from the examination of mineral and fluid inclusions in Witwatersrand pyrites, shows three major types of pyrite: (i) detrital pyrite (rounded pyrite crystals transported into the depositional environment); (ii) synsedimentary pyrite (round and rounded aggregates of fine-grained pyrite formed within the depositional environmen); and (iii) authigenic pyrite (newly crystallized and/or recrystallized pyrite formed after deposition). The detrital grains contain mineral inclusions such as biotite, feldspar, apatite, zircon, sphene, and various ore minerals, and fluid inclusions with daughter minerals. Most of the inclusions are incompatible with an origin by sulphidization. Recrystallized authigenic pyrite occurs in large quantities but only in horizons or localities which have been subjected to higher temperatures during the intrusion or extrusion of younger volcanic rocks. Important additional findings are the often substantial amounts of pyrite and small amounts of particles of gold found in Archaean granites (Hallbauer, 1982) as possible source rocks for the Witwatersrand detritus. Large differences in Ag and Hg content between homogeneous single gold grains within a hand specimen indicate a lack of metamorphic homogenization. The influence of metamorphism on the Witwatersrand pyrites can therefore be described as only slight and generally negligible.

BURIAL HISTORY OF THE EASTERN OFFICER BASIN, SOUTH AUSTRALIA

1995 ◽  
Vol 35 (1) ◽  
pp. 307 ◽  
Author(s):  
R. Moussavi-Harami ◽  
D. I. Gravestock
Keyword(s):  
South Australia ◽  
Bounded Sequence ◽  
Source Rocks ◽  
Sediment Loading ◽  
Burial History ◽  
Fine Grained ◽  
Accommodation Space ◽  
The North ◽  
History Of ◽  
Well Data

The intracratonic Officer Basin of central Australia was formed during the Neoproterozoic, approximately 820 m.y. ago. The eastern third of the Officer Basin is in South Australia and contains nine unconformity-bounded sequence sets (super-sequences), from Neoproterozoic to Tertiary in age. Burial history is interpreted from a series of diagrams generated from well data in structurally diverse settings. These enable comparison between the stable shelf and co-existing deep troughs. During the Neoproterozoic, subsidence in the north (Munyarai Trough) was much higher than in either the south (Giles area) or northeast (Manya Trough). This subsidence was related to tectonic as well as sediment loading. During the Cambrian, subsidence was much higher in the northeast and was probably due to tectonic and sediment loading (carbonates over siliciclastics). During the Early Ordovician, subsidence in the north created more accommodation space for the last marine transgression from the northeast. The high subsidence rate of Late Devonian rocks in the Munyarai Trough was probably related to rapid deposition of fine-grained siliciclastic sediments prior to the Alice Springs Orogeny. Rates of subsidence were very low during the Early Permian and Late Jurassic to Early Cretaceous, probably due to sediment loading rather than tectonic sinking. Potential Neoproterozoic source rocks were buried enough to reach initial maturity at the time of the terminal Proterozoic Petermann Ranges Orogeny. Early Cambrian potential source rocks in the Manya Trough were initially mature prior to the Delamerian Orogeny (Middle Cambrian) and fully mature on the Murnaroo Platform at the culmination of the Alice Springs Orogeny (Devonian).

Sign in / Sign up

Export Citation Format

Share Document