Recent Geodynamics: from Crustal Movements to Monitoring Critical Objects

Izvestiya, Physics of the Solid Earth - This paper addresses the evolution of the views on the subject and methods of geodynamics over the past fifty years. The problems of the metrological...     

Analysis of the Results of Deformation Monitoring by the Inclinometer System at the Vladimir Filanovsky Field

Izvestiya, Atmospheric and Oceanic Physics - The system of geodynamic monitoring at the Vladimir Filanovsky oil and gas condensate field is presented. The technologies for data transfer to the...     

Elevated Mercury in the Water of the Angara River Source: A Response to Geodynamic Impacts and Strong Earthquakes

Doklady Earth Sciences - The mercury concentrations in the water of the Angara River Source (runoff of Lake Baikal) are compared to temporal distributions of earthquakes of various magnitudes that...     

A New Finding of a Docodontan (Mammaliaformes,Docodonta) in the Lower Cretaceous of Western Siberia

Doklady Earth Sciences - The first finding of the docodontan (a lower molar of Sibirotherium sp.) from the Bol’shoi Kemchug 3 locality (Ilek Formation, Lower Cretaceous) in Krasnoyarsk...     

An Instrument Platform for Above-Water Measurements of the Ocean’s Surface and Atmosphere

Izvestiya, Atmospheric and Oceanic Physics - An automated instrument platform is designed to install remote sensing instruments for measurements made from stationary coastal pedestals or offshore...     

A 640 kyr geomagnetic and palaeoclimatic record from Lake Baikal sediments

Magnetic remanence vectors for 1737 samples from two ∼100 m cores of Lake Baikal sediments are reported along with complete magnetic susceptibility profiles obtained from a pass-through system. Chronological control is established by means of two independent correlations; first, by matching susceptibility variations to the oceanic oxygen isotope record and second, by matching the relative palaeointensity variations to the SINT-800 global reference curve. These both imply an average deposition rate of 15 cm kyr^–1 and a basal age of ∼640 ka. Spectral analysis reveals the presence of Milankovitch signals at ∼100 kyr (eccentricity), ∼41 kyr (obliquity) and ∼23 and ∼19 kyr (precession). Stable remanence vectors are almost all of normal polarity. The few exceptions comprise brief intervals of low and/or negative inclinations which probably represent geomagnetic excursions. However, these are far less numerous than the high sedimentation rate would lead one to expect. Furthermore, only four of them can be readily matched to the—still poorly understood—global pattern. These are the Laschamp, the Albuquerque, the Iceland Basin and perhaps the West Eifel excursions which occurred at ∼38 000, ∼146 000, at 180 000–190 000 and at 480 000–495 000 yr ago, respectively.     

Sedimentation processes and new age constraints on rifting stages in Lake Baikal: results of deep-water drilling

 With this paper we present a first attempt to combine the direct results on lithology, composition and age dating in the boreholes BDP-93, BDP-96 and BDP-97 with geological and seismic data from the areas where those sections were drilled. The sedimentary environments represented by the BDP boreholes are markedly different and possess characteristic lithological features. The results of the deep drilling provide the essential means for testing numerous age models used in geological reconstructions of the Lake Baikal rifting dynamics. Neither the basin-wide unconformity interpreted from seismic data, nor the interpreted change from shallow-water to deep-water facies at the boundary of the seismic stratigraphic complexes were found in the BDP-96 boreholes on Academician Ridge. Also, lithology does not support the proposed reconstructions of intense lake level fluctuations and transgressions during the Pliocene at Academician Ridge. The continuous deep-water hemipelagic sedimentation at Academician Ridge has existed for the past 5 Ma. The beginning of an intense rifting phase of the Neobaikalian sub-stage and related drastic changes in sedimentation processes were interpreted on seismic sections as the basin-wide unconformity B10. Different age estimates for this boundary ranged from Late Pliocene (3.5 Ma) to Plio-Pleistocene boundary. As shown by BDP-96 borehole, B10 is associated with a lithological change from diatomaceous ooze to dense silty clay and not with an erosional contact. The new age for this boundary in BDP-96 is approximately 2.5 Ma. This new age constraint suggests that the upper sedimentary strata of Northern Baikal (1.5–1.7 km thick) have formed during the past 2.5 Ma with average sedimentation rates of 60–70 cm/ka. The BDP-93 boreholes at Buguldeika suggest that uplift in Primorsky Range took place prior to 1.07–1.31 Ma, a date which exceeds the age of previous geological models. Received: 12 March 1999 / Accepted: 10 February 2000     

Low-frequency flux-density measurements and spectral features of millisecond pulsars

Radio flux-density measurements for a large sample of millisecond pulsars at a low frequency of 102 MHz are presented. Using higher frequency measurements, we construct their spectra in the frequency range from 102 MHz to 4.8 GHz, the widest one studied to date. The spectra of millisecond and normal pulsars have been found to differ. The spectra of millisecond pulsars have no low-frequency turnover typical of normal pulsars. The absence of a low-frequency turnover in the spectrum suggests that the emitting regions of millisecond and normal pulsars differ in geometry, which we interpret by deviation of the magnetic field from a dipole one or by compactness of the emitting region.