泰国近岸古环境Toarcian-Aalenian期风暴沉积初探

JurassicdepositsoftheMalayanPeninsula(Thailand)arestratigraphicallylimitedtoToarcianandAalenianonly(Meesook&Sha,2010,andliteraturecitedtherein).Thesearerepresentedbywidespectrumofbothclasticandcarbonaterockswithfulldevelop-mentoftransitionalones.Inthemiddlepartofpenin-sula(vicinityofKrabi)distributionofJurassicfaciessuggestoccurrenceoffullmarinepalaeoenvironmentsinNEpartofitwithgentletransitionbylagoonal(brackish?)andtidalenvironmentsuptoterrestrialonesintheSWpartofpeninsula.Sectionsstudied,closetoThungSongcity,arerepresentedby20mthicksequenceofthin-beddedlimestonesandmarlsoftheKhlongMinFormation,mostprobablylagoonalpalaeoenvironments(transitional=restrictedma-rine-brackish),indicatedbyspecificbenthicfaunadominatedbydifferentkindofethologicalgroupofbivalves–infaunal,epifaunalandencrusted(epibion-tic)specieslikeProtocardia,Praemytilus,Modiolus,Myrene,andActinostreon.Verycharacteristicisalackoffullmarine,stenohaline,otherinvertebrates–brachiopods,crinoids,echinoidsetc.