A palaeoecological analysis of late quaternary sapropels from the Mediterranean Ridge

• Other Authors: Barry, Darren
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2020
• Subjects: Palaeoecology; Sapropels; Mediterranean; Foraminifera; Quaternary; Planktonic foraminifera
• Online Access: https://dspace.mic.ul.ie/handle/10395/2928

A PALAEOECOLOGICAL ANALYSIS OF LATE QUATERNARY SAPROPELS FROM THE MEDITERRANEAN RIDGE By Darren Barry The sedimentary sequences of the Eastern Mediterranean Sea are interspersed by blackcoloured, organic rich deposits called sapropels. Ranging in thickness from a few millimeters to as much as tens of centimetres these sedimentary layers have been deposited throughout the late Cenozoic. Despite intensive research the exact environmental conditions that led to the deposition of these sapropels are not yet fully understood. Using planktonic foraminifera as a proxy, this research focuses on the deposition of several sapropels. In addition to the more commonly studied sapropels (S1 and S5) S3 and S6 have also been investigated. The principle aim of this research is to reconstruct the palaeoenvironmental conditions during these depositional events. In addition to using the traditional method of analysing faunal assemblages, particular emphasis will be placed on accessing the test size variation of individual species of planktonic foraminifera. This technique has been applied to other events in Earth’s history but not in relation to sapropel deposition. The research is based on data extracted from ODP core 969A (latitude 33.84N, longitude 24.88E, water depth 2200.3 m). With the exception of S1 (7cm), the thickness of each sapropel (S3 – 28cm; S5 – 28cm; S6 – 41cm) allows each event to be analysed at a sufficiently high resolution. One aspect of this study related to the palaeoenvironmental reconstruction of two cores from open ocean sites. Using micropalaeontological data along with multivariate statistical analysis has allowed detailed analysis of palaeoenvironmental variability since the Last Glacial Maximum (LGM). In addition, estimates of sea surface temperature (SST) shows a gradual climate amelioration from the LGM to present. A unique aspect of this research examined the mean test size data of two shallow and one deep dwelling planktonic foraminiferal species over two sapropel events. Particular attention was ...