Sedimentary sequences and microbial mats of Iberian saline lakes as tools for the investigation of modern and sub-recent environmental processes

Abstract

This thesis aimed to provide deeper insights the effectiveness of hypersaline lacustrine settings and microbial mats as palaeoenvironmental archives, while attempting to further understand the spatial complexities of the depositional and sub-depositional settings of saline lakes and characteristics of microbial mats within them. To achieve this, key objectives included the sedimentological, geochemical and hydrological analysis of sediments from Laguna Salada de Chiprana and other lacustrine settings throughout the Iberian Peninsula, combined with analysis of the macro and micro-morphology and geochemistry of microbial mats. The first chapter presents a high-resolution sedimentological dataset of Lake Chiprana and describes and interprets facies variations throughout the last three to four centuries in order to establish the spatio-temporal variability in the depositional settings of the lake. This is succeeded by a µXRF-based dataset presented in the second data chapter, which provides insights into the key intrinsic and extrinsic geochemical processes acting upon Lake Chiprana throughout the lake. Finally, the third data chapter presents a study of the mineralogical and hydrochemical aspects of the lake in order to provide supporting evidence as to the palaeoenvironmental changes identified in the sedimentary sequence and to determine the hydrochemical evolution of the lake under different environmental domains. In addition, the petrography, morphology and biogeochemistry of microbial mats and microbialites occurring both within Laguna Salada de Chiprana and three other Iberian lakes were studied extensively in the fourth and fifth data chapters. In the fourth chapter, computerised tomographical scans and petrographical analyses were employed to determine the mesoscale and microscale structures associated with mats from each of the lakes, This allowed for the characterisation of the morphology and texture of mat structures and the pertinent processes responsible for their formation, lending deeper insights into the small-scale processes and environments of deposition that contributed to their development.

Date of Award	31 Dec 2023
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Roy Wogelius (Supervisor) & Stefan Schroeder (Supervisor)