Matches in SemOpenAlex for { <https://semopenalex.org/work/W1990938845> ?p ?o ?g. }
Showing items 1 to 99 of
99
with 100 items per page.
- W1990938845 endingPage "267" @default.
- W1990938845 startingPage "255" @default.
- W1990938845 abstract "Abstract A major issue in understanding weathering processes is to determine to what extent fabrics, structures and volumes from the parent rock are preserved through the weathering profile. Iso-element mass balance methods (IMB) are often used to estimate volume changes during progressive weathering, based on the assumption that a given element (either Ti, Zr or Th) is not mobile. The petrofabric of the weathered material is often characterized by a mimetic replacement of primary minerals that fully preserve the primary fabric. This suggests an isovolume weathering as volume change must be associated with shape change due to boundary conditions not allowing horizontal strains. So collapse or dilation should induce vertical compaction or constriction, respectively. The weak petrofabric of weathered materials may be precisely quantified using the anisotropy of low-field magnetic susceptibility technique (AMS). This paper reports, for the first time, a combined IMB and AMS study of two different environments: a complex lateritic sequence on Precambrian metamorphic rocks in Cameroon and a weathering profile on a Pleistocene basaltic flow in Morocco. The lateritic profile, divided into a lower saprolite zone (>12 m) and an upper nodular iron-rich unit (4 m), is characterized by neoformed magnetic minerals (goethite/hematite/spinels) and a weak but rather consistent magnetic fabric. Saprolitization, which induces low susceptibility values (50×10−9 m3/kg), preserves the linear tectonic fabric of the parent gneiss. AMS evidence for isovolumetric weathering agrees with Th based IMB, while Ti and Zr partly indicate apparent collapse and dilation (up to 50%), respectively. Ferralitization in the nodular iron crust, which enhances susceptibilities (500 to 700×10−9 m3/kg, due to spinel phases), induces drastic reductions in anisotropy due to multiple generation of neoformed minerals destroying primary fabric. However, a weak horizontal planar magnetic fabric suggests compaction, in agreement with Th and Ti based IMB while Zr would indicate isovolume weathering. Conversely, in the one meter thick weathering profile on basalt, the strong susceptibility (1.5 to 3×10−6 m3/kg) is dominated by inherited titanomaghemite grains which totally preserve the weak magmatic fabric of the fresh basalt. This again suggests that volume change is minor, while Ti and Zr based IMB indicate 20 to 50% of dilation. In both examples, large volume changes inferred from the IMB in units showing preserved primary AMS fabric appear unrealistic. Our AMS study, together with the large discrepancies between the IMB results produced by various elements, indicate that the assumption of immobility of a given element is probably not fulfilled all along these profiles. Isovolumetric weathering in the saprolitic zone may be more widespread than suggested by IMB results." @default.
- W1990938845 created "2016-06-24" @default.
- W1990938845 creator A5003026688 @default.
- W1990938845 creator A5042678660 @default.
- W1990938845 creator A5049082542 @default.
- W1990938845 creator A5086159138 @default.
- W1990938845 date "1999-04-01" @default.
- W1990938845 modified "2023-09-25" @default.
- W1990938845 title "Volumetric changes in weathered profiles: iso-element mass balance method questioned by magnetic fabric" @default.
- W1990938845 cites W124423239 @default.
- W1990938845 cites W1558861973 @default.
- W1990938845 cites W1608779755 @default.
- W1990938845 cites W18115758 @default.
- W1990938845 cites W1972442953 @default.
- W1990938845 cites W1978359460 @default.
- W1990938845 cites W1981183613 @default.
- W1990938845 cites W1986140763 @default.
- W1990938845 cites W1997654347 @default.
- W1990938845 cites W2000014168 @default.
- W1990938845 cites W2008717706 @default.
- W1990938845 cites W2013484851 @default.
- W1990938845 cites W2016620466 @default.
- W1990938845 cites W2017031661 @default.
- W1990938845 cites W2038462363 @default.
- W1990938845 cites W2044479101 @default.
- W1990938845 cites W2051576762 @default.
- W1990938845 cites W2055143611 @default.
- W1990938845 cites W2059675029 @default.
- W1990938845 cites W2063258367 @default.
- W1990938845 cites W2067380728 @default.
- W1990938845 cites W2073863738 @default.
- W1990938845 cites W2087937118 @default.
- W1990938845 cites W2090826258 @default.
- W1990938845 cites W2094919208 @default.
- W1990938845 cites W2129181201 @default.
- W1990938845 cites W2152857640 @default.
- W1990938845 cites W2159154761 @default.
- W1990938845 cites W2189481810 @default.
- W1990938845 cites W2265155142 @default.
- W1990938845 cites W2317872349 @default.
- W1990938845 cites W2592970199 @default.
- W1990938845 cites W2807940962 @default.
- W1990938845 cites W29815705 @default.
- W1990938845 cites W3015978974 @default.
- W1990938845 cites W3146554266 @default.
- W1990938845 doi "https://doi.org/10.1016/s0012-821x(99)00024-2" @default.
- W1990938845 hasPublicationYear "1999" @default.
- W1990938845 type Work @default.
- W1990938845 sameAs 1990938845 @default.
- W1990938845 citedByCount "24" @default.
- W1990938845 countsByYear W19909388452015 @default.
- W1990938845 countsByYear W19909388452016 @default.
- W1990938845 countsByYear W19909388452020 @default.
- W1990938845 countsByYear W19909388452021 @default.
- W1990938845 crossrefType "journal-article" @default.
- W1990938845 hasAuthorship W1990938845A5003026688 @default.
- W1990938845 hasAuthorship W1990938845A5042678660 @default.
- W1990938845 hasAuthorship W1990938845A5049082542 @default.
- W1990938845 hasAuthorship W1990938845A5086159138 @default.
- W1990938845 hasBestOaLocation W19909388452 @default.
- W1990938845 hasConcept C114793014 @default.
- W1990938845 hasConcept C127313418 @default.
- W1990938845 hasConcept C168031717 @default.
- W1990938845 hasConcept C199289684 @default.
- W1990938845 hasConcept C40724407 @default.
- W1990938845 hasConcept C71924100 @default.
- W1990938845 hasConcept C99508421 @default.
- W1990938845 hasConceptScore W1990938845C114793014 @default.
- W1990938845 hasConceptScore W1990938845C127313418 @default.
- W1990938845 hasConceptScore W1990938845C168031717 @default.
- W1990938845 hasConceptScore W1990938845C199289684 @default.
- W1990938845 hasConceptScore W1990938845C40724407 @default.
- W1990938845 hasConceptScore W1990938845C71924100 @default.
- W1990938845 hasConceptScore W1990938845C99508421 @default.
- W1990938845 hasIssue "3-4" @default.
- W1990938845 hasLocation W19909388451 @default.
- W1990938845 hasLocation W19909388452 @default.
- W1990938845 hasLocation W19909388453 @default.
- W1990938845 hasLocation W19909388454 @default.
- W1990938845 hasLocation W19909388455 @default.
- W1990938845 hasOpenAccess W1990938845 @default.
- W1990938845 hasPrimaryLocation W19909388451 @default.
- W1990938845 hasRelatedWork W1652433593 @default.
- W1990938845 hasRelatedWork W2008590108 @default.
- W1990938845 hasRelatedWork W2014633439 @default.
- W1990938845 hasRelatedWork W2020535921 @default.
- W1990938845 hasRelatedWork W2077938109 @default.
- W1990938845 hasRelatedWork W2089972609 @default.
- W1990938845 hasRelatedWork W2090030785 @default.
- W1990938845 hasRelatedWork W2099589822 @default.
- W1990938845 hasRelatedWork W2314337543 @default.
- W1990938845 hasRelatedWork W4252257704 @default.
- W1990938845 hasVolume "167" @default.
- W1990938845 isParatext "false" @default.
- W1990938845 isRetracted "false" @default.
- W1990938845 magId "1990938845" @default.
- W1990938845 workType "article" @default.