FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W1988627424> ?p ?o ?g. }

• W1988627424 endingPage "4137" @default.
• W1988627424 startingPage "4115" @default.
• W1988627424 abstract "Fifty-eight rock chips from fifteen samples of sedimentary rocks from the Ramah Group (approximately 1.9 Ga) in northeastern Labrador, Canada, were analyzed for major and minor elements, including C and S, to elucidate weathering processes on the Earth's surface about 1.9 Ga ago. The samples come from the Rowsell Harbour, Reddick Bight, and Nullataktok Formations. Two rock series, graywackes-gray shales of the Rowsell Harbour, Reddick Bight and Nullataktok Formations, and black shales of the Nullataktok Formation, are distinguishable on the basis of lithology, mineralogy, and major and trace element chemistry. The black shales show lower concentrations than the graywackes-gray shales in TiO2 (0.3-0.7 wt% vs. 0.7-1.8 wt%), Al2O3 (9.5-20.1 wt% vs. 13.0-25.0 wt%), and sigma Fe (<1 wt% vs. 3.8-13.9 wt% as FeO). Contents of Zr, Th, U, Nb, Ce, Y, Rb, Y, Co, and Ni are also lower in the black shales. The source rocks for the Ramah Group sediments were probably Archean gneisses with compositions similar to those in Labrador and western Greenland. The major element chemistry of source rocks for the Ramah Group sedimentary rocks was estimated from the Al2O3/TiO2 ratios of the sedimentary rocks and the relationship between the major element contents (e.g., SiO2 wt%) and Al2O3/TiO2 ratios of the Archean gneisses. This approach is justified, because the Al/Ti ratios of shales generally retain their source rock values; however, the Zr/Al, Zr/Ti, and Cr/Ni ratios fractionate during the transport of sediments. The measured SiO2 contents of shales in the Ramah Group are generally higher than the estimated SiO2 contents of source rocks by approximately 5 wt%. This correction may also have to be applied when estimating average crustal compositions from shales. Two provenances were recognized for the Ramah Group sediments. Provenance I was comprised mostly of rocks of bimodal compositions, one with SiO2 contents approximately 45 wt% and the other approximately 65 wt%, and was the source for most sedimentary rocks of the Ramah Group, except for black shales of the Nullataktok Formation. The black shales were apparently derived from Provenance II that was comprised mostly of felsic rocks with SiO2 contents approximately 65 wt%. Comparing the compositions of the Ramah Group sedimentary rocks and their source rocks, we have recognized that several major elements, especially Ca and Mg, were lost almost entirely from the source rocks during weathering and sedimentation. Sodium and potassium were also leached almost entirely during the weathering of the source rocks. However, significant amounts of Na were added to the black shales and K to all the rock types during diagenesis and/or regional metamorphism. The intensity of weathering of source rocks for the Ramah Group sediments was much higher than that of typical Phanerozoic sediments, possibly because of a higher PCO2 in the Proterozoic atmosphere. Compared to the source rock values, the Fe3+/Ti ratios of many of the graywackes and gray shales of the Ramah Group are higher, the Fe2+/Ti ratios are lower, and the sigma Fe/Ti ratios are the same. Such characteristics of the Fe geochemistry indicate that these sedimentary rocks are comprised of soils formed by weathering of source rocks under an oxygen-rich atmosphere. The atmosphere about 1.9 Ga was, therefore, oxygen rich. Typical black shales of Phanerozoic age exhibit positive correlations between the organic C contents and the concentrations of S, U, and Mo, because these elements are enriched in oxygenated seawater and are removed from seawater by organic matter in sediments. However, such correlations are not found in the Ramah Group sediments. Black shales of the Ramah Group contain 1.7-2.8 wt% organic C, but are extremely depleted in sigma Fe (<1 wt% as FeO), S (<0.3 wt%), U (approximately l ppm), Mo (<5 ppm), Ni (<2 ppm), and Co (approximately 0 ppm). This lack of correlation, however, does not imply that the approximately 1.9 Ga atmosphere-ocean system was anoxic. Depletion of these elements from the Ramah Group sediments may have occurred during diagenesis." @default.
• W1988627424 created "2016-06-24" @default.
• W1988627424 creator A5008107187 @default.
• W1988627424 creator A5053877531 @default.
• W1988627424 creator A5057785083 @default.
• W1988627424 creator A5076151390 @default.
• W1988627424 date "1997-10-01" @default.
• W1988627424 modified "2023-10-12" @default.
• W1988627424 title "Geochemistry of ∼1.9 Ga sedimentary rocks from northeastern Labrador, Canada" @default.
• W1988627424 cites W1971546354 @default.
• W1988627424 cites W1973633128 @default.
• W1988627424 cites W1974091969 @default.
• W1988627424 cites W1975437092 @default.
• W1988627424 cites W1978301477 @default.
• W1988627424 cites W1980600502 @default.
• W1988627424 cites W1984985833 @default.
• W1988627424 cites W1988110935 @default.
• W1988627424 cites W1990174891 @default.
• W1988627424 cites W1992068942 @default.
• W1988627424 cites W1993001470 @default.
• W1988627424 cites W1995706097 @default.
• W1988627424 cites W2000768310 @default.
• W1988627424 cites W2001363398 @default.
• W1988627424 cites W2005468830 @default.
• W1988627424 cites W2009862239 @default.
• W1988627424 cites W2010925982 @default.
• W1988627424 cites W2013915127 @default.
• W1988627424 cites W2015783623 @default.
• W1988627424 cites W2020384898 @default.
• W1988627424 cites W2023662669 @default.
• W1988627424 cites W2024219233 @default.
• W1988627424 cites W2025486891 @default.
• W1988627424 cites W2027706871 @default.
• W1988627424 cites W2029401070 @default.
• W1988627424 cites W2029599884 @default.
• W1988627424 cites W2030045843 @default.
• W1988627424 cites W2033962701 @default.
• W1988627424 cites W2036763175 @default.
• W1988627424 cites W2037859029 @default.
• W1988627424 cites W2039174342 @default.
• W1988627424 cites W2040883093 @default.
• W1988627424 cites W2042711314 @default.
• W1988627424 cites W2042757256 @default.
• W1988627424 cites W2046769368 @default.
• W1988627424 cites W2049065847 @default.
• W1988627424 cites W2050320960 @default.
• W1988627424 cites W2053274509 @default.
• W1988627424 cites W2054104477 @default.
• W1988627424 cites W2055752884 @default.
• W1988627424 cites W2060400888 @default.
• W1988627424 cites W2065208888 @default.
• W1988627424 cites W2069006321 @default.
• W1988627424 cites W2072014794 @default.
• W1988627424 cites W2073407409 @default.
• W1988627424 cites W2073863738 @default.
• W1988627424 cites W2074749531 @default.
• W1988627424 cites W2079249535 @default.
• W1988627424 cites W2081374165 @default.
• W1988627424 cites W2082972472 @default.
• W1988627424 cites W2084603288 @default.
• W1988627424 cites W2085228574 @default.
• W1988627424 cites W2086312073 @default.
• W1988627424 cites W2087536853 @default.
• W1988627424 cites W2089740954 @default.
• W1988627424 cites W2089831496 @default.
• W1988627424 cites W2094828960 @default.
• W1988627424 cites W2122014250 @default.
• W1988627424 cites W2137149868 @default.
• W1988627424 cites W2320645792 @default.
• W1988627424 cites W2332986039 @default.
• W1988627424 cites W2563452930 @default.
• W1988627424 doi "https://doi.org/10.1016/s0016-7037(97)00214-7" @default.
• W1988627424 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/11540490" @default.
• W1988627424 hasPublicationYear "1997" @default.
• W1988627424 type Work @default.
• W1988627424 sameAs 1988627424 @default.
• W1988627424 citedByCount "747" @default.
• W1988627424 countsByYear W19886274242012 @default.
• W1988627424 countsByYear W19886274242013 @default.
• W1988627424 countsByYear W19886274242014 @default.
• W1988627424 countsByYear W19886274242015 @default.
• W1988627424 countsByYear W19886274242016 @default.
• W1988627424 countsByYear W19886274242017 @default.
• W1988627424 countsByYear W19886274242018 @default.
• W1988627424 countsByYear W19886274242019 @default.
• W1988627424 countsByYear W19886274242020 @default.
• W1988627424 countsByYear W19886274242021 @default.
• W1988627424 countsByYear W19886274242022 @default.
• W1988627424 countsByYear W19886274242023 @default.
• W1988627424 crossrefType "journal-article" @default.
• W1988627424 hasAuthorship W1988627424A5008107187 @default.
• W1988627424 hasAuthorship W1988627424A5053877531 @default.
• W1988627424 hasAuthorship W1988627424A5057785083 @default.
• W1988627424 hasAuthorship W1988627424A5076151390 @default.
• W1988627424 hasConcept C122792734 @default.
• W1988627424 hasConcept C127313418 @default.
• W1988627424 hasConcept C149347711 @default.
• W1988627424 hasConcept C171701179 @default.

• next