Title : ( The Campanian paleoenvironment: Inferences based on benthic foraminifera from northeastern Iran )
Authors: Sreepat Jain , Seyed Mohsen Niazi , Ahmed Awad Abdelhady , Mohammad Vahidinia , Mohamad Hosein Mahmudy Gharaie ,
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Abstract
ThebenthicforaminiferafromtheCampanianrocks(GlobotruncanitaelevatatoGlobotruncanaaegyptiacazones) exposed in the Kopeh-Dagh Basin (northeast Iran) are studied quantitatively to reconstruct the Campanian paleoenvironment.Basedonunconstrainedheriarchialclustering,NonmetricMultidimensionalScaling(NMDS), andanalysisofsimilarity(ANOSIM),threestatisticallysignificantbenthicforaminiferalassemblagesarenoted, Paralabamina lunata (lowerandupper), Haplophragmoidesspp.,andGyroidinoides nitida.Based onbenthicforaminiferal marker species, the following paleodepths are assigned - lower P. lunata: upper bathyal; upper P. lunata: upper-middle bathyal boundary; Haplophragmoides spp. and G. nitida: outer neritic. The P. lunata Assemblage can be further subdivided into a lower Coryphostoma incrassata-dominated interval, whereas the upperintervalisP.lunata-dominated,andreflectsachangeinthequalityoffood;theupperexperiencedhigher inputoffreshphytodetritus.TheoverallP.lunataAssemblagereflectsastablebottomwaterenvironment.The Haplophragmoidesspp.Assemblageischaracterizedbyreducedpaleoproductivityandenvironmentalinstability, whereastheG.nitidaAssemblageismarkedbyincreasingoligotrophywithinawell-oxygenatedbottomwater andventilatedbasinalconditions.ThePartialLeastSquaresregressionyieldedsignificantcorrelationswith% Planktic(positive;proxyforsealevel)and%agglutinatedspecies(negative;proxyforshallowdepthsandlow organic-flux); theReducedMajorAxisregression modelsalsoyieldedsignificant negativecorrelationswith % agglutinatedand%infaunalspecies(nutrientavailability),suggestingthatthesefactorswereresponsibleforthe inferredbenthicforaminiferaldistributionpatterns.Twogloballycomparableshallowingtrendsarealsonotedone in the middle of the R. calcarata Zone (= Haplophragmoides spp. Assemblage) and the other in the G. aegyptiacaZone(=GyroidinoidesnitidaAssemblage)thatcoincidewithKCa6andKCa7sequenceboundariesand lowstands, respectively. For the KCa6 event, the occurrence of Spiroplectammina (= Haplophragmoides spp. Assemblage)representsashallow-waterouterneriticfaunainvasioneventwithinadeeperupperbathyalsetting (=ParalabaminalunataAssemblage)andfortheKCa7event,asimilarshallowingfromupper-middlebathyal boundary toouterneriticdepthsisnoted(= G.nitidaAssemblage),andattributedtoeustasyandbasinalpaleohighsandlows.
Keywords
, Foraminifera assemblage Paleobathymetry Paleoproductivity Paleoxygenation Kopeh, Dagh Basin Eustasy
@article{paperid:1080763,
author = {Sreepat Jain and سید محسن نیازی and Ahmed Awad Abdelhady and Vahidinia, Mohammad and Mahmudy Gharaie, Mohamad Hosein},
title = {The Campanian paleoenvironment: Inferences based on benthic foraminifera from northeastern Iran},
journal = {palaeogeography, palaeoclimatology, palaeoecology},
year = {2020},
volume = {554},
number = {109823},
month = {September},
issn = {0031-0182},
pages = {109823--23},
numpages = {-109800},
keywords = {Foraminifera assemblage Paleobathymetry Paleoproductivity Paleoxygenation Kopeh-Dagh Basin Eustasy},
}
%0 Journal Article
%T The Campanian paleoenvironment: Inferences based on benthic foraminifera from northeastern Iran
%A Sreepat Jain
%A سید محسن نیازی
%A Ahmed Awad Abdelhady
%A Vahidinia, Mohammad
%A Mahmudy Gharaie, Mohamad Hosein
%J palaeogeography, palaeoclimatology, palaeoecology
%@ 0031-0182
%D 2020
