Diatoms play a major role in carbon and silicon cycles, and thus diatom-bearing sediments represent an archive of past climatic and environmental settings. In shallow-marine and freshwater environments, the accumulation of diatom frustules forms a sedimentary rock called diatomite. While most global-scale studies of diatom-bearing sediments focus on deep-sea sites, shallow-marine and freshwater diatomites are studied mainly at a regional level. To address this problem, we present a global-scale compilation of diatomite occurrences spanning the Palaeogene (∼66 to ∼23 Ma). This period was characterized by initial extreme warmth, followed by prolonged cooling, disrupted by short-term climatic events called hyperthermals and by a number of palaeoceanographic and palaeogeographic changes. The aim of this compilation is to determine the response of diatom production to Palaeogene environmental fluctuations by examining the influence of climate, tectonic activity, and ocean circulation on diatomite deposition. Although climatic factors appear to have had an indirect impact, our study suggests that palaeogeographic and palaeoceanographic changes were key drivers of diatomite deposition during the Palaeogene, particularly from the Early Eocene Climatic Optimum (∼53 to ∼49 Ma) onwards. In fact, our compilation suggests the absence of diatomite deposition in epicontinental seas between ∼46 and ∼44 Ma, whereas diatomites did not begin to accumulate in open-ocean environments until ∼43.5 Ma. Moreover, we observe that regional climate and volcano-tectonic activity have had an impact on the deposition of freshwater diatomites.

New data on finds of representative diatom assemblages in the marine Cenozoic section of West Kamchatka (Kvachina Bay) are presented. Planktonic species of stratigraphic importance were found in the assemblages. Analysis of stratigraphic occurrence of various taxa in the section resulted in the identification of a series of biostratigraphic units with the rank of local zones. Correlation of the assemblages with the North Pacific diatom zonation is outlined. The early Oligocene to early Miocene age of the host deposits is concluded.

The current state of the North Pacific Cenozoic diatom zonation is reviewed. The high resolution of diatom zonation is shown, which is comparable to that of groups of calcareous planktonic microfossils. The significance of diatom assemblages for the dating and correlation of various Tertiary marine sediments in the North Pacific is discussed. Recent examples of subdivision of the Oligocene-Neogene sequences of this region and dating of geological events on the zonal basis are given.

Modern data on diatom algae – unicellular microorganisms with siliceous frustule composing Class Bacillariophyceae, are reviewed. Brief characteristic of biology, morphology, frustule structure and its elements, principles of diatom systematics, and also biogeography and ecology are given. A role of diatoms in sedimentation and peculiarities of preservation of their remains in bottom sediments are discussed. Special attention is paid to issues of effective application of data on fossil diatoms for detailed biostratigraphic subdivision, dating and correlation of sedimentary successions (first of all, marine deposits) as well as for paleoenvironmental reconstructions. General characteristic of diatom zonations proposed for marine Cretaceous and Cenozoic sediments is given. Main features of diatom evolution are discussed.

The results of paleomagnetic research of sediments from the Cenozoic key section of West Kamchatka at the Kvachina Bay are presented. In total, 152 samples collected from 121 stratigraphic levels of the 480-m-thick section are studied. The behavior of scalar magnetic parameters k, NRM, and Qn and magnetic anisotropy suggests that sedimentary rocks from the Kvachina Bay section were not subjected to significant deformations and substantial secondary alterations. A succession of 21 monopolar intervals combined into 10 magnetozones is identified within the section. Taking into account the correlation with reference levels of local zones based on diatoms, the correlation of recognized magnetozones with the Geomagnetic Polarity Time Scale (chrons C17 to C6) is outlined.

The results of stratigraphic studies carried out in the process of international deep-sea drilling in the last fifty years are presented. They make a great contribution to development and improvement of the methods for detailed stratigraphic studies and dating of marine sedimentary sequences as well as reconstructions of past oceanological and climatic events. The results obtained are of great methodological importance for stratigraphic investigations of the whole Phanerozoic. The distinguished Cenozoic biostratigraphic zones can really be traced across the whole tropical and subtropical area. The study data on planktonic microorganism (calcareous and siliceous) assemblages which were an integral part of Mesozoic and Cenozoic marine ecosystems made a considerable contribution to these works. These assemblages developed over time against the background of variable oceanic circulation and sedimentation conditions, changes in deep and surface water productivity, water temperature, etc. In general, the evolution trend of biotic communities reflects the development and reorganization stages of the past ecosystems. All these data make it possible to reveal the real sequence of not only biotic but also abiotic events (climatic, oceanographic, and eustatic) in the World Ocean for the last 70–75 million years.