2. PROXY Information
Long-duration (10 7 years) records of sea level, ice volume, and temperature over the past 50 Ma are limited to ocean sediment deposits. Although other proxy records exist (e.g., from isotope analysis of fossil tooth enamel [ Zanazzi et al., 2007 ] or sediment records from an incised river valley [ Peters et al., 2010 ]), these are of a too short duration to be included in this review. Long-term (10 7 years) records are presently limited to sequence stratigraphy records of sea level [ Miller et al., 2005a ], Mg/Ca proxy records of DST [ Lear et al., 2000 ; Billups and Schrag, 2003 ], and records of oxygen isotopes (? 18 O), which are a mixed climate signal [ Zachos et al., 2001 ]. Other proxies, such as the tetraether index (TEX86) and the alkenone unsaturation index (U k? 37), have been used to create intermediate-duration (10 6 years) SST records.
Sequence stratigraphy off passive continental margins provide tabs on regional sea level for the past fifty Ma and also offered timescales [ Vail ainsi que al., 1977 ; Haq ainsi que al., 1987 ; Miller mais aussi al., 2005a ; Kominz mais aussi al., 2008 ]. Depositional sequences bounded by unconformities (attacks out-of nondeposition and you will/otherwise counters away from erosion) inform you changes in local sea-level. [1998 , 2005a] , Kominz et al. , and you may Browning mais aussi al. ).
By truthfully dating sequences and you may inferring during the last liquid breadth throughout the depositional phases regarding lithofacies and you can biofacies models, a quantitative guess of sea-level due to time should be composed (to own a complete discussion look cougar life for Miller mais aussi al
Vail et al. set up a way for inferring around the world sea-level by correlating sequences out-of numerous depositional basins. It functions lead to producing the fresh “Haq contour,” which was stated at that time as an international eustatic listing regarding sea level [ Haq ainsi que al., 1987 ]. Miall try important of approach employed by Haq et al. because it assumes the matchmaking of sequences are exact sufficient to allow for correlation around the numerous depositional sinks. not, the duration of a few of the sequences is commonly lower than the age error guess. Miall showed you to definitely sequences made out of an arbitrary number creator which have an equivalent years problems you will definitely create good correlation to the Haq bend. It’s undecided whether the sequences is the results of good global sea level rule or produced by local procedure, and also make relationship all over several sinks dubious [ Christie-Blick et al., 1988 ]. Almost every other criticism provides focused on the deficiency of method of getting data you to definitely composed this new Haq contour, for example separate confirmation of one’s number is not possible [ Miall, 1992 ]. Given these types of fundamental flaws, Miall ideal that Haq curve specifically might be quit and you can work should be concerned about separate better-old ideas, like those talked about from the after the.
Within the last fifteen years, numerous really-old sediment cores in one region, this new Jersey (NJ) margin regarding northeastern Us, were used to produce a sequence stratigraphy listing from ocean level for the past 10–100 Ma (sea level having 0–9 Ma from the research by the Miller et al. [2005a] is estimated of an effective calibration of your own ? 18 O record once the Nj succession stratigraphy checklist are unfinished of 0 to eight Ma) [ Miller mais aussi al., 2005a ; Kominz ainsi que al., 2008 ] (find Shape step 1). If you take into consideration compaction, loading, and you can subsidence of your own sediment key (the brand new backstripping approach), a regional sea-level record was made [ Browning ainsi que al., 2008 ]. Brand new sequences are dated having fun with a combination of biostratigraphy, magnetostratigraphy, and you will strontium isotope stratigraphy, delivering age manage much better than ±0.5 Ma [ Kominz et al., 2008 ], that is a significant upgrade towards ±step 3 Ma many years errors of Haq curve [ Miall, 1992 ].