Messinian deep‐water turbidites and glacioeustatic sea‐level changes in the North Atlantic: Linkage to the Mediterranean salinity crisis

Abstract

Our benthic foraminiferal data clearly indicate eight layers of deep‐water turbidites during the Messinian (MTL 1‐8) and one in the early Pliocene (PTL 1) in Ocean Drilling Program Leg 105, Site 646B. These deep‐water tuibidite deposits are characterized by highly concentrated agglutinated marsh benthic foraminifera (e.g., Trochammina cf. squamata, Ammotium sp. A, Miliammina fusca), rounded quartz, polished thick‐walled benthic foraminifera, wood fragments, plant seeds, plant fruit, and highly concentrated mica and are interbedded with sediments containing deep‐water benthic faunas. We suggest these turbidites deposited during sea‐level low stands (∼80–100 m below sea level), and their ages are tentatively correlated to 6.59, 6.22, 6.01, 5.89, 5.75, 5.7, 5.65, 5.60, and 5.55 Ma, respectively, based on the Messinian oxygen isotope enrichments at Site 552A of Deep Sea Drilling Project Leg 81. The turbidites layers during the late Messinian, coeval with frequent climate changes suggested by six oxygen enrichment excursions of Site 552A, may have been in part linked to the late Messinian evaporite deposits in the Mediterranean Basin. The most profound climate changes at 5.75 and 5.55 Ma may have been related to the Lower and Upper Evaporites in the Mediterranean Basin.An electronic supplement of this material may be obtained on adiskette or Anonymous FTP from KOSMOS .AGU.ORG, (LOGIN toAGU's FTP account using ANONYMOUS as the username and GUESTas the password. Go to the right directory by typing CD APEND. TypeLS to see what files are available. Type GET and the name of the file toget it. Finally, type EXIT to leave the system. (Paper 96PA00572,Messinian deep‐water turbidites and glacioeustatic sea‐level changes inthe North Atlantic: Linkage to the Mediterranean Salinity Crisis, JijunZhang and David B. Scott). Diskette may be ordered from AmericanGeophysical Union, 2000 Florida Avenue, N.W., Washington, D.C.20009; $15.00. Payment must accompany order.