Materials and Methods

Abstract

This chapter provides an overview of the materials and methods used in the study of the terrestrial and offshore mud volcanoes of the Black Sea region. The general strategy includes geomorphological, geological, geophysical, gas-geochemical, paleontological, and micropaleontological dimensions. The geomorphological dimension covers observations of the terrain/sea bottom relief in the search for mud volcanoes. As a rule, mud volcanoes on land are characterized by rounded positive forms of relief comprising hills up to 60 m in height. The hills are constituted largely of mud breccia. Some mud volcanoes look like small, rounded puddles filled with bubbling liquid mud. In the sea, the geomorphological dimension entails bathymetrical (morphometrical) analysis of bottom relief performed by multibeam echo sounder and side-scan sonar that enable mapping of local bottom elevations that could represent mud volcanoes. The geophysical dimension involves seismoacoustic profiling, multichannel seismic profiling, cross and ring seismic sounding (tomography) on reflected and refracted waves, in situ geothermal measurements, detailed gravimetric and magnetometric survey, sounding the formation of the electromagnetic field in order to determine the conductivity parameters of the bottom sediments and the layer of gas hydrates, and laboratory experimental thermodynamic studies of the physical properties of artificial samples of hydrate-containing bottom sediments. Seeps and gas emanations from mud volcanoes were studied by echo sounding with the help of modern digital echo sounders. The geological dimension applies to both terrestrial mud volcanoes and adjacent recessed synclines as well as offshore mud volcanoes. This dimension focuses on the study of sediments within mud volcanic structures, including identification of lithological, grain-size, and mineralogical properties of the sediments recovered by drilling, coring, and dredging. The gas-geochemical dimension covers geochemical investigation of gases emitted by mud volcanoes. The paleontological and micropaleontological dimensions investigated mollusks, foraminifers, ostracods, and nematodes.