Archaean Sedimentary Rocks and Their Relation to the Composition of the Archaean Continental Crust

McLennan, S. M.; Taylor, Stuart Ross

doi:10.1007/978-3-642-70001-9_3

Cited by 43 publications

(40 citation statements)

References 74 publications

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“…(La/Yb) n , (Gd/Yb) n -отношения нормированы по хондриту [Boynton, 1984]. AS -средний состав архейских глинистых сланцев [McLennan, Taylor, 1984]. терригенного материала элементов (Th, РЗЭ, Y, Cr, Ni, Co, Sc) изученные сланцы близки к среднему составу архейских аргиллитов (рис.…”

Section: состав метатерригенных породunclassified

“…терригенного материала элементов (Th, РЗЭ, Y, Cr, Ni, Co, Sc) изученные сланцы близки к среднему составу архейских аргиллитов (рис. 4), формирование которых рассматривается как результат смешения в различных пропорциях материала, образованного при эрозии пород основного и кислого составов [McLennan, Taylor, 1984]. Следовательно, можно полагать, что осадочные протолиты гранат-ставроли-товых сланцев формировались за счет источни-ков разной кремнекислотности.…”

Section: состав метатерригенных породunclassified

“…Нормировано по хондриту [Boynton, 1984] и среднему архейскому глинистому сланцу (AS) [McLennan, Taylor, 1984].…”

Section: состав метатерригенных породunclassified

“…В сравнении с постархейскими глинистыми сланца-ми архейские терригенные породы характеризуются большей изменчивостью содержания редких эле-ментов, что обусловлено локальным характером их источников сноса [McLennan, Taylor, 1984]. Это обстоятельство дает возможность использовать геохимические и изотопные характеристики осадочных пород для анализа состава пород в питающей провинции, тогда как датирование детритовых цирконов несет информацию о возрасте источников сноса.…”

Section: Introductionunclassified

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THE U-Pb AGE AND Lu-Hf ISOTOPE COMPOSITION OF DETRITAL ZIRCON FROM METASEDIMENTARY ROCKS OF THE ONOT GREENSTONE BELT (Sharyzhalgay uplift, southern Siberian craton)

2014

GiG

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Section: состав метатерригенных породunclassified

“…Нормировано по хондриту [Boynton, 1984] и среднему архейскому глинистому сланцу (AS) [McLennan, Taylor, 1984].…”

Section: состав метатерригенных породunclassified

Section: Introductionunclassified

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THE U-Pb AGE AND Lu-Hf ISOTOPE COMPOSITION OF DETRITAL ZIRCON FROM METASEDIMENTARY ROCKS OF THE ONOT GREENSTONE BELT (Sharyzhalgay uplift, southern Siberian craton)

2014

GiG

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“…For many elements, the sediments have compositions indistinguishable from average arc andesite (Wilson, 1989) and Costa Rican andesites, suggesting a volcanic provenance for the deformed wedge sediments. Relative to upper continental crust and postArchean shales (McLennan and Taylor, 1984), the sediment column has lower SiO 2 and higher Al 2 O 3 , Ba/Ce, Ba/Rb, and Zr/Nb, which is consistent with the addition of detrital grains with basaltic-andesite or andesite composition (Carr and Rose, 1987). The homogeneity of the deformed wedge sediments is remarkable and contrasts with the larger variability seen at Site 1041 (see "Geochemistry" section, "Site 1041" chapter, this volume).…”

Section: X-ray Fluorescence Analyses Of the Solid Phasesmentioning

confidence: 99%

Site 1040

1997

Proceedings of the Ocean Drilling Program

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Coring totals:Type: APC; No: 1; Cored: 9.5 m; Recovered: 9.58 m (100.8%) Formation:Subunit P1A (0−9.58 mbsf): Olive green silty clay to clayey silt with debris flows and silty sands (Pliocene−?Pleistocene) HOLE 1040B Logging while drillingPrincipal results: The lithostratigraphic and biostratigraphic objectives included determining the nature and age of the sedimentary wedge, the relationship of underthrust units to those of the reference section at Site 1039, and the implications for the balance of mass and fluids between the trench sequence and the underthrust and wedge sequences. Another important objective was to determine the structural fabric of both the sedimentary wedge and the underthrust section. We were mostly successful in achieving these objectives, drilling through the décollement and the entire underthrust sedimentary sequence and into gabbro intrusions very similar to those in Site 1039. Because logging-while-drilling (LWD) operations were only partially successful at this site, we did not obtain a full in situ physical properties data set for correlations with Site 1039. The sedimentary wedge overlies the same three sedimentary units and one igneous unit as were drilled at Site 1039 (Fig.

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Size and composition of the MORB+OIB mantle reservoir

Hofmann

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Goldstein

2022

Preprint

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Most efforts to characterize the size and composition of the mantle that complements the continental crust have assumed that the mid-ocean ridge basalt (MORB) source is the incompatible-element depleted residue of continental crust extraction. The use of Nd isotopes to model this process led to the conclusion that the "depleted MORB reservoir" is confined to the upper ˜30% of the mantle, leaving the lower mantle in a more "primitive" state. Here we use Nb/U and Ta/U to evaluate mass and composition of the mantle reservoir residual to continent extraction and find that it exceeds 67% of the total mantle. Thus the (Nb,Ta)/U-based mass balance conflicts with the ε(Nd)-based mass balance, and this invalidates the classical 3-reservoir silicate Earth model (continental crust, depleted mantle, primitive mantle). Including the combined MORB + ocean island basalt (OIB) sources in the ε(Nd)-based mass balance does not reconcile the conflict as it would require their average ε(Nd) to be [?]3.0, much lower than observed MORB+OIB ε(Nd) averages. We resolve this conflict by invoking an additional, "earlyenriched reservoir" (EER), formed prior to extraction of significant continental crust, but now hidden or lost. This EER differs from EERs previously invoked by having no Nb-Ta anomaly. We suggest that it originated as an early mafic crust, which had unfractionated (Nb,Ta)/U but fractionated Sm/Nd ratios. The corresponding "early-depleted" reservoir (EDR) generated the present-day continental crust and the "residual mantle" MORB-OIB reservoir, which occupies at least 70% of the present-day mantle and is only moderately depleted in incompatible trace elements.

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Archaean Sedimentary Rocks and Their Relation to the Composition of the Archaean Continental Crust

Cited by 43 publications

References 74 publications

THE U-Pb AGE AND Lu-Hf ISOTOPE COMPOSITION OF DETRITAL ZIRCON FROM METASEDIMENTARY ROCKS OF THE ONOT GREENSTONE BELT (Sharyzhalgay uplift, southern Siberian craton)

THE U-Pb AGE AND Lu-Hf ISOTOPE COMPOSITION OF DETRITAL ZIRCON FROM METASEDIMENTARY ROCKS OF THE ONOT GREENSTONE BELT (Sharyzhalgay uplift, southern Siberian craton)

Site 1040

Size and composition of the MORB+OIB mantle reservoir

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