Designation:D4823−95(Reapproved2019)StandardGuideforCoreSamplingSubmerged,UnconsolidatedSediments1ThisstandardisissuedunderthefixeddesignationD4823;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thisguidecoverscore-samplingterminology,advan-tagesanddisadvantagesofdifferenttypesofcoresamplers,core-distortionsthatmayoccurduringsampling,techniquesfordetectingandminimizingcoredistortions,andmethodsfordissectingandpreservingsedimentcores.1.2Inthisguide,samplingproceduresandequipmentaredividedintothefollowingcategoriesbasedonwaterdepth:samplingindepthsshallowerthan0.5m,samplingindepthsbetween0.5mand10m,andsamplingindepthsexceeding10m.Eachcategoryisdividedintotwosections:equipmentforcollectingshortcoresandequipmentforcollectinglongcores.1.3Thisguideemphasizesgeneralprinciples.Onlyinafewinstancesarestep-by-stepinstructionsgiven.Becausecoresamplingisafield-basedoperation,methodsandequipmentmustusuallybemodifiedtosuitlocalconditions.Thismodi-ficationprocessrequirestwoessentialingredients:operatorskillandjudgment.Neithercanbereplacedbywrittenrules.1.4Drawingsofsamplersareincludedtoshowsizesandproportions.Thesesamplersareofferedprimarilyasexamples(orgenericrepresentations)ofequipmentthatcanbepurchasedcommerciallyorbuiltfromplansintechnicaljournals.1.5Thisguideisabriefsummaryofpublishedscientificarticlesandengineeringreports.Thesereferencesarelistedinthisguide.Thesedocumentsprovideoperationaldetailsthatarenotgiveninthisguidebutareneverthelessessentialtothesuccessfulplanningandcompletionofcoresamplingprojects.1.6ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.7Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-pr...
