Planktonic foraminifera of ODP Hole 107-654A

The late Miocene sediments of the Tyrrhenian ODP Site 654 encompass a deepening sequence which begins with glauconite shallow water sands followed by a rapid transition to deep water sediments and culminates with dolomitic mudstones associated with Messinian evaporites. The sequence compares well with the so-called 'Sahelian cycle' and with post-orogenic cycles recognized in peninsular Italy and Sicily. The studied interval, consisting of 55 m thick nannofossil oozes, belongs to the Globorotalia suterae subzone and lower part of the Globorotalia conomiozea Zone, indicating late Tortonian and early Messinian age, respectively. Biomagnetostratigraphic correlation assigns the Tortonian/ Messinian boundary an age of 6.44-6.45 Ma. In addition, six main events have been recognized, based on the range of keeled globorotaliids and coiling direction changes of keeled and unkeeled globorotaliids, which have been correlated to the geomagnetic time-scale. Comparison with North Atlantic sites and land sections of the Guadalquivir basin and northern Morocco provides good correlations with the events documented in these areas. In particular, Event IV, which predates the FO of Globorotalia conomiozea, may be used to recognize the Tortonian/Messinian boundary in extra-Mediterranean areas where G. conomiozea is missing. Variations in the distribution of different species of Globigerinoides are related to changes in the surficial marine environment. Although no clear trends can be recognized on the oxygen and carbon isotope records of Globigerinoides obliquus, the parallelism between the occurrence of low salinity species (G. sacculifer) and peaks of low 5180 values, as well as that of normal salinity species (G. obliquus) and peaks of high d18O values, suggests strong local changes of environmental conditions. The high amplitude of the fluctuations of d18O values suggests important variations in the salinity of the Tyrrhenian Sea, related to a rapidly changing water budget. The major feature of the carbon isotope record is a large decrease between 7.0 and 6.95 Ma, which therefore predates the 6.2 Ma global 'carbon shift'.

Discarge compilation from The Global River Discharge (RivDIS) Project

The Global River Discharge (RivDIS) data set contains monthly discharge measurements for 1018 stations located throughout the world. The period of record varies widely from station to station, with a mean of 21.5 years. These data were digitized from published UNESCO archives by Charles Voromarty, Balaze Fekete, and B.A. Tucker of the Complex Systems Research Center (CSRC) at the University of New Hampshire. River discharge is typically measured through the use of a rating curve that relates local water level height to discharge. This rating curve is used to estimate discharge from the observed water level. The rating curves are periodically rechecked and recalibrated through on-site measurement of discharge and river stage.