Mineralogy and origin of Tertiary interbasaltic clays from the Faeroe Islands, Northeastern Atlantic

Parra, M.; Delmont, P.; Dumon, Jonathan; Ferragne, A.; Pons, Jean-Claude

doi:10.1180/claymin.1987.022.1.06

Cited by 18 publications

(7 citation statements)

References 22 publications

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“…The strong decrease in accumulation rate towards the top of the lower basalt formation is supported by geological observations. The lower formation lava flows are separated by palaeosol (red clay) and tuff Parra et al 1987). In the Lopra drill-hole the sediments form about 2~ of the lava pile ).…”

Section: Accumulation Ratesmentioning

confidence: 99%

“…It is dominated by thick compound flows which often exceed 30 m in thickness in the lower part of the formation. The flows either have no sediments in between or they are separated by thin beds of red tuff rather than soil Parra et al 1987). Thus, only 30-40 tuff beds averaging 30 cm in thickness have been recorded through the 1.4 km thick middle formation (unpublished mapping by the author).…”

Section: Accumulation Ratesmentioning

confidence: 99%

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Structure, composition and age of the Faeroe basalt plateau

Waagstein

1988

100

152

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The lower Tertiary Faeroe basalt plateau is centred around the Faeroe Islands in the northern part of the supposed Faeroe-Rockall microcontinent. It consists of subaerial lavas, divided into three formations. The lower formation is probabty thickest (> 3 km) in the southern or central part of the islands, whereas the middle and upper formations are probably thickest (> 2 km in total) just N of the Faeroes, close to the line of opening between the Faeroes and Greenland. The lower formation consists of tholeiites relatively low in TiO2. The lower part of the middle formation shows an upward progression from high-Ti olivine tholeiites to high-Ti thoteiites, whereas the entire upper and rest of the middle formations consists of a contrasting population of high-Ti tholeiites and low-Ti MORB-like olivine tholeiites to tholeiites. The MORB type is confined to the northern Faeroes, increasing in abundance upwards. Similar MORB-like basalts have been recovered from further SW along the microcontinent (Faeroe Bank, Bill Bailey Bank, Lousy Bank and the Rockall Plateau), being associated with high-Ti tholeiites near the Faeroes and away from the Tertiary line of opening (Faeroe and Bill Bailey Banks). In addition, transitional to mildly alkaline basalts have been recovered on the E side of the Faeroe Bank Channel and on Bill Bailey Bank.Based on field revision of the magnetostratigraphy of the Sower formation it is tentatively suggested that the lower formation was extruded during chrons C26R to C25N and the two higher formations during C24R. Accumulation rates seem to have varied systematically and to have been related to the abundance and type of sediments between the lavas, which may indicate that extrusive activity ceased in the Faeroes before the opening of the NE Atlantic in C24R, and explain the presence of conjugate strike-slip faults in the NW Faeroes.The spatial distribution of the various basalt types fits a model of shifting axes of intraplate volcanicity, shifting from the Faeroes to E Greenland and in part back again.

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Section: Accumulation Ratesmentioning

confidence: 99%

Section: Accumulation Ratesmentioning

confidence: 99%

Structure, composition and age of the Faeroe basalt plateau

Waagstein

1988

100

152

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“…The thickness of related zonal WM reaches 30 m. Their continental ori gin is established without doubt. It is suggested that WM were formed under conditions close to the present day tropical environment (Karpoff, 1980;Nilsen and Kerr, 1978;Noak et al, 1979;Parra et al, 1987).…”

Section: Weathering Mantles As Indicators Of Paleoclimate In the Eartmentioning

confidence: 98%

Main aspects of the theory of ore-bearing weathering mantles in the 21st century

et al. 2011

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The theory of ore bearing weathering mantles (WM) was developed at the Institute of Geological Sciences, USSR Academy of Sciences (currently the Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences) in the 1930s. I.I. Ginzburg was an originator of this theory. The extensive new data on the bauxite , Ni , Au , REE bearing and other rare metal WM has led to the development of a general theory of exogenic ore deposits, which has been confirmed by forecasting, prospecting, and exploration of solid mineral resources. On considering the current status of the WM theory based on the results of precision research methods (XRD, IRS, EPR spectroscopy, DTA, electron micros copy, etc.), the main aspects determining its advance can be pointed out: (1) physicochemical simulation of WM formation; (2) identification and study of nanominerals in WM; (3) study of the contribution of organic matter to weathering; and (4) use of WM as indicators of climatic change in the Earth's history. As is presently established, WM are natural chemical reactors of nanoparticles of various minerals. The progress in nanom ineralogy of WM will facilitate the choice of rational methods of mining and recovery of valuable compo nents. As has been proved by electron microscopy, fossilized microbial communities, biofilms, and cyanobac terial mats occur in almost all WM. The importance of studying mutual relations of inorganic and organic substances of WM in more detail is evident. Development of the idea of using WM as indicators of paleocli mate will provide insights into global changes in the environment and complement the results obtained by traditional paleoclimatic methods. This aspect is especially topical in connection with widely discussed prob lem of global climatic warming.

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“…Negative stratigraphic profile is inferred from Lopra-1/1A borehole. primarily of fine-grained clay minerals, especially smectites and kaolinites (Parra et al, 1987), which are dispersed in fine-grained densinite, or form isolated layers (Fig. 6E, F).…”

Section: Maceral Compositionmentioning

confidence: 99%

“…The coal deposits are mentioned peripherally in several publications within basic geological descriptions of the Faroe Islands (e.g., Ellis et al, 2002;Laier et al, 1997;Lund, 1989;Parra et al, 1987;Passey, 2014;Noe-Nygaard, 1969, 1970;Stokes, 1874). Nevertheless, they have not yet been systematically studied in terms of quality.…”

Section: Introductionmentioning

confidence: 99%

Petrological and geochemical characteristics of Palaeogene low-rank coal on the Faroe Islands: Restricted effects of alteration by basaltic lava flows

Kuboušková

Krmíček

Coufalík

et al. 2016

International Journal of Coal Geology

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The first combined petrographic and geochemical investigation of coal from the Faroe Islands was performed as a case study to understand thermal effects from basaltic lava flows on immature coal. The samples were divided into two distinct groups: "normal" coal (xylite and detroxylite) and "altered organic matter" (charcoal and organic particles dispersed in samples rich in altered clastic mineral components or enriched via hydrothermal fluids). The "normal" coal consists primarily of huminite-group material dominated by ulminite. The proportions of material from inertinite and liptinite groups vary from sample to sample. The studied macerals are anisotropic with no observed reaction rims or vacuoles. According to the mean ulminite reflectance in combination with ultimate and proximate analyses, the coal reached the lignite and subbituminous stages. The maceral compositions together with coal palynology indicate a predominance of gelified wood-derived tissues and demonstrate that the coal evolved in wet forest swamps under limno-telmatic to telmatic conditions. Alteration effects on immature coals from overlying basalt flows were relatively limited. Due to relatively rapid heat loss from the basaltic lava, as verified by the presence of volcanic glass (tachylyte), its imposed thermal effects resulted only in development of a thin "anthracite-like" crust on samples with no elevated coal rank. Associated hydrothermal fluids induced coal hydrofracturing with subsequent mineral precipitation and decomposition of the ambient feldspar-rich volcaniclastic sediments. Altered organic matter is enriched in SiO 2 , Al 2 O 3 and FeO tot , as well as in trace elements such as Ni and Cr. In contrast, these samples are depleted in Hg (b10 ppb).

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Mineralogy and origin of Tertiary interbasaltic clays from the Faeroe Islands, Northeastern Atlantic

Abstract: The Faeroe archipelago in the northeastern part of the Atlantic Ocean contains numerous red Tertiary interbasaltic beds (Rasmussen & Noe-Nygaard, 1970;L6vlie, 1975). Rubified formations of the same age and comparable composition have been studied on the Iceland-

Cited by 18 publications

References 22 publications

Structure, composition and age of the Faeroe basalt plateau

Structure, composition and age of the Faeroe basalt plateau

Main aspects of the theory of ore-bearing weathering mantles in the 21st century

Petrological and geochemical characteristics of Palaeogene low-rank coal on the Faroe Islands: Restricted effects of alteration by basaltic lava flows

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