Pecome progractively envicheo with desth. Strontium ise the apper cco m of core kKAR-1, devalened from coral, Eivalve, anc wnclea-rock samples, indicates the presence of four maior eubaerial uncoaformities, which have heen corfirmed by a newly developed strontiia Leutepe straticraphy on age and facies 2quivalent sediments cf core OOR-17, Cayoen, carbon, and strontium isotepe and concentration data of microsamples (0.5 ta 1.0 ng) of sparcy calcite cements and adjacent rock Matra. document the recerd cf matecric chreetic diagenesis attendant with these ¢ea tevel lowetands. Strontium concentration positively cavaries with Sr sup @7 /Sr sup 6 and ..delta.. C sup 13. In contrast, Gr sup 987 /Sr sip Go negatively covarigs with ..delta.. C sup 13 variations. Sr sup &7 ‘Se eup G&S values indicate the scurce cf carbenate cementation because stroatium is derived from dissalution of overlying aragenitic allachems. when the dissclving aragcnite 1s of similar age, and hence cof similar etrentism isataopic compesation, lowstancd phreatic calcites preserve the cepceitictai strontium isatope age. However, when the aragonite scurce has a Significently different etreontivm isotecpe compositicen lowstand pnreatic Calsitez record -« diageretic etromtium iectope ace. mecird - = SDTALTG File 1C3: 1744ét2 EVR-a91i2iin7 Jicrle: cevelstion of reef and atoll owmergin certonates, usper Eocene me, Enewetal, Marsbeil leiands wHey Scrlenger, f.4. 1 Srierce era Technolog Brea, cA CUSA> vial meeting ef the American S2ecciatior of Petroleum if Hoveton, TX, US4 . (United states) w 243 5. Conference Dates gt-£3 “272, Mar 1928 her BoSc1= ronal artizie: Conte-ence literature L Toorsai onneuncement: EDEBIOn stofiles ET> (crecgy Téeccselogy Data cichanged., IMT (DOE contractor) Work Cacatioan: United States Ststract: Two welie drilled along the margin of Enewetal Atell penetrated eporeximately 1900 m of upper Eccerne, Oligecens. and lewer Miecane cartenates. Strontium isetepe etratigraphy indicates relatively contirnucus Gepiasitien of carbonate from 40 Ma ta 20 Ma. Depasitional environments show a graduzel] tbasirward progracation of facies with elope carbonates passing upward into fore-reef, reef, beck-reef, and lageonal carbonates. Slape strata contain wackestones and packstones with submarine-cenented lithaclasts, cereal, coralline algae fragments, Beathic retaiine forams, flanktenic ferans, and echinocerm fragments. Fore-reef strata are dominattly oackstones and EFourdstanes containing large pieces af ceral, ebuidant benthic forems, coralline algae fragments, stromatopercids( ), end mince planktosic forans, Reef and near-reaf zeciments include coralgal roundstorze ard grzinetenes with abuncant benthic forems. Halimeda anc Tiliclid ferems a-e common in legoonwarc parts of the beck reef. Spance borings, ge¢pecal steuctures, end fractures are common in reef and Sryecces’ stezta, Lageonal strata zre wackestones end peckstones with I00%b31