Diatomaceous origin of siliceous shale in Eocene lake beds of central British Columbia

2005 ◽  
Vol 42 (2) ◽  
pp. 231-241 ◽  
Author(s):  
George E Mustoe
Keyword(s):  
British Columbia ◽  
Lacustrine Sediments ◽  
X Ray Diffraction ◽  
Element Geochemistry ◽  
X Ray ◽  
Diagenetic Alteration ◽  
Extant Species ◽  
Geologic Record ◽  
Siliceous Shale ◽  
Lake Beds

The abundance of diatoms in Neogene lacustrine sediments and their apparent scarcity in Paleogene deposits have long perplexed geoscientists, but siliceous shales from Eocene lake beds of central British Columbia provide new insights. Major element geochemistry, X-ray diffraction patterns, and relict diatom frustules suggest that Eocene beds at Horsefly, McAbee, and Princeton originated as lacustrine diatomite that underwent diagenetic alteration to produce siliceous shale. The combination of high SiO2 and low Al2O3 values and the presence of opal-CT X-ray diffraction peaks provide a distinctive geochemical fingerprint for biogenic silica deposits that have been remineralized. The discovery of diatomaceous geochemical signatures in siliceous shales may prove to be a useful tool for extending the geologic record of diatoms, perhaps helping to reduce the apparent discrepancy between fossil evidence and evolutionary interpretations based extant species.

Origin of Turbidites In Deep Lake Geneva (France–Switzerland) In the Last 1500 Years

2015 ◽  
Vol 85 (12) ◽  
pp. 1455-1465 ◽  
Author(s):  
Katrina Kremer ◽  
Juan Pablo Corella ◽  
Thierry Adatte ◽  
Emmanuel Garnier ◽  
gregor Zenhäusern ◽  
...  
Keyword(s):  
Sediment Cores ◽  
Lacustrine Sediments ◽  
Historical Event ◽  
Trace Element Geochemistry ◽  
Lake Geneva ◽  
X Ray Diffraction ◽  
Deep Lake ◽  
Deep Basin ◽  
Element Geochemistry ◽  
X Ray

Abstract:  Turbidites in lacustrine sediments are commonly used to assess the frequencies of flood events and/or earthquakes. Understanding the origin of those deposits is key to adequately assess the sources and triggers of such events in large lacustrine systems. Ca/Ti X-ray fluorescence core scanner and magnetic susceptibility values on sediment cores of the deep basin of Lake Geneva are used as a provenance indicator of the turbidites either from the Dranse or Rhone deltas or from the slopes not influenced by deltaic input. This tool is validated by mineralogical analyses (X-ray diffraction), major-, and trace-element geochemistry (X-ray fluorescence). Based on this discrimination method, the turbidites deposited in the central part of the deep basin can be classified regarding their origin. From all identified turbidites, four turbidites are chosen based on their large depositional area and volumes and are studied in more detail in order to better understand the processes leading to turbidite deposition in the deep basin. The age intervals of these turbidites were compared to the historical records of extreme events in the region of Lake Geneva. These turbidites can be related to extreme floods, earthquakes, and “spontaneous” delta collapses. The cause of two turbidites could not be identified precisely due to large dating intervals that did not allow attributing a specific historical event to the turbidite layer. Overall, this study provides a tool in classifying the turbidites in deep Lake Geneva and exemplifies that defining the cause of turbidites is complex although it remains a prerequisite for paleohydrology and paleoseismology studies.

THE CLAY MINERALS IN SOME BRITISH COLUMBIA SUBSOILS

1962 ◽  
Vol 42 (2) ◽  
pp. 296-301 ◽  
Author(s):  
J. S. Clark ◽  
J. E. Brydon ◽  
H. J. Hortie
Keyword(s):  
British Columbia ◽  
Diffraction Analysis ◽  
Clay Minerals ◽  
Clay Mineralogy ◽  
X Ray Diffraction ◽  
The South ◽  
Parent Materials ◽  
X Ray ◽  
Northeastern Part ◽  
Montmorillonitic Clay

X-ray diffraction analysis was used to identify the clay minerals present in fourteen subsoil samples that were selected to represent some more important clay-bearing deposits in British Columbia. The clay mineralogy of the subsoils varied considerably but montmorillonitic clay minerals tended to predominate in the water-laid deposits of the south and illite in the soil parent materials of the Interior Plains region of the northeastern part of the Province.

THE OCCURRENCE OF GIBBSITE IN A BRITISH COLUMBIA SOIL

1978 ◽  
Vol 58 (4) ◽  
pp. 529-533
Author(s):  
N. M. MILES ◽  
G. C. SCOTT ◽  
A. J. GREEN
Keyword(s):  
British Columbia ◽  
Vancouver Island ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Identity ◽  
Ir Bands

Gibbsite occurs in all horizons of an Orthic Dystric Brunisol near Port Alberni, Vancouver Island. The structural identity of gibbsite was established by (i) X-ray diffraction maxima at 4.85, 4.38 and 2.38 Å, which disappeared at 260 °C, (ii) principal IR bands at 3,615, 3,520, 3,428 and 3,380 cm−1 and (iii) a DTA endotherm near 300 °C.

Clay mineralogy and potassium status of selected soils in the glacial Lake Agassiz region of central Manitoba

1999 ◽  
Vol 79 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Michael T. Aide ◽  
Gary J. Cwick ◽  
Mark F. Cummings
Keyword(s):  
Lacustrine Sediments ◽  
Clay Mineralogy ◽  
Glacial Lake ◽  
X Ray Diffraction ◽  
Lake Agassiz ◽  
X Ray ◽  
Fine Grained ◽  
Potassium Fixation ◽  
Glacial Lake Agassiz ◽  
Reduced Intensity

The clay mineralogy of the soil is important in that it can affect potassium (K) availability, particularly if vermiculite is present. Large areas of Glacial Lake Agassiz in Manitoba contain fine-grained lacustrine sediments that support boreal forest vegetation. The purpose of this investigation was to identify the clay mineralogy of several commonly occurring soils and document its influence on soil fertility, particularly K availability. The soils were classified as either Eluviated Eutric Brunisols or Orthic Eutric Brunisols. X-ray diffraction analysis verified that vermiculite, hydrous mica and kaolinite were the principal clay minerals in these soils. Vermiculite was demonstrated to have hydroxy Al-interlayers and the amount of vermiculite decreased in the deeper soil horizons. Smectite was present in the Btj horizons of the Eluviated Eutric Brunisols, while trace amounts of chlorite were present in every inorganic horizon. Quantity/intensity curves for K and an experimental estimate of the K-fixation potential indicated that the Ae horizons of several Eluviated Eutric Brunisols supported higher K activities in the soil solution and that K-fixation was greater in subsurface horizons. Potassium fixation and the quantity/intensity curves for selected horizons of the Orthic Eutric Brunisols were nearly identical and each showed a reduced intensity to maintain the aqueous activity of K. Key words: Potassium fixation, vermiculite, quantity/intensity

THE OCCURRENCE OF CHLORITE AND VERMICULITE IN THE CLAY FRACTION OF THREE BRITISH COLUMBIA SOILS

1959 ◽  
Vol 39 (2) ◽  
pp. 246-253
Author(s):  
A. A. Theisen ◽  
G. R. Webster ◽  
M. E. Harward
Keyword(s):  
British Columbia ◽  
Clay Fraction ◽  
Clay Mineralogy ◽  
Vancouver Island ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Past ◽  
Surface Samples

The clay mineralogy of surface samples from three soils on Vancouver Island which had been used in fertility experiments was determined by X-ray diffraction. Chlorite was identified as the predominant mineral in all three soils. Vermiculite was present in discrete units in the Chemainus soil and interstratified with chlorite in the Fairbridge and Merville soils. Kaolinite may also have been a constituent; this could not be determined since the use of certain criteria, proposed in the past for the identification of kaolinite in the presence of chlorite, proved unsuccessful. It was concluded that no universal criterion, which holds true in all cases, exists for distinguishing kaolinite in the presence of chlorite.

scholarly journals Development Characteristics of Shale Lithofacies in the Longmaxi Formation and their Main Controlling Factors in the Changning Area, South Sichuan Basin, SW China

2021 ◽  
Vol 9 ◽  
Author(s):  
Qingsong Tang ◽  
Lu Zhou ◽  
Lei Chen ◽  
Xiucheng Tan ◽  
Gaoxiang Wang
Keyword(s):  
Seismic Data ◽  
Sichuan Basin ◽  
Spatial Variations ◽  
X Ray Diffraction ◽  
Thin Sections ◽  
Longmaxi Formation ◽  
X Ray ◽  
Lower Silurian ◽  
Longmaxi Shale ◽  
Siliceous Shale

Based on core observations, thin sections, X-ray diffraction (XRD), and seismic data, the lithofacies types in the organic-rich Longmaxi shale (Lower Silurian) in the Changning area of the southern Sichuan Basin were identified. The factors controlling the spatial variations in the shale lithofacies and the influences of the shale lithofacies on shale gas development were also analyzed. Results indicate that there are seven main types of shale lithofacies in the Long11 sub-member of the Longmaxi Formation, including siliceous shale (S-1), mixed siliceous shale (S-2), carbonate-rich siliceous shale (S-3), clay-rich siliceous shale (S-4), carbonate/siliceous shale (M-1), mixed shale (M-2), and argillaceous/siliceous shale (M-4). A vertical transition from the carbonate shale association + mixed shale association at the bottom of the sub-member to a siliceous shale association and mixed shale association + siliceous shale at the top generally appears in the Long11 sub-member. The shale lithofacies of the Long11 sub-member also laterally change from the central depression (low-lying area) to the geomorphic highland in the east and west parts of the Changning area. The spatial variations in shale lithofacies in the Long11 sub-member of the Changning area were mainly controlled by palaeogeomorphology and relative sea level. The geomorphic highland area is dominated by carbonate-rich siliceous shale and mixed siliceous shale, but the depression (low-lying area) is mainly dominated by mixed siliceous shale and argillaceous/carbonate shale.

Occurrence and biogeographic significance of Heliaster (Echinodermata: Asteroidea) from the Pliocene of southwest Florida

1988 ◽  
Vol 62 (01) ◽  
pp. 126-132 ◽  
Author(s):  
Douglas S. Jones ◽  
Roger W. Portell
Keyword(s):  
Central American ◽  
Eastern Pacific ◽  
Whole Body ◽  
Marine Fauna ◽  
Western Atlantic ◽  
Southwest Florida ◽  
Extant Species ◽  
Geologic Record ◽  
Central American Isthmus

Whole body asteroid fossils are rare in the geologic record and previously unreported from the Cenozoic of Florida. However, specimens of the extant species,Heliaster microbrachiusXantus, were recently discovered in upper Pliocene deposits. This marks the first reported fossil occurrence of the monogeneric Heliasteridae, a group today confined to the eastern Pacific. This discovery provides further non-molluscan evidence of the close similarities between the Neogene marine fauna of Florida and the modern fauna of the eastern Pacific. The extinction of the heliasters in the western Atlantic is consistent with the pattern of many other marine groups in the region which suffered impoverishment following uplift of the Central American isthmus.

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