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Results of the activity of Quaternary glaciations in the western Baikal area are considered based on new factual material. Also, the problem of the formation of

Assuming orbital modulation of Pleistocene climate cycles, we have generated a new time scale for the Asian geochemical limnic record in the BDP-96-2 Baikal and the KDP-01 Hovsgol cores and updated the chronologies for the global marine δ¹⁸O and Vostok ice-gas records. The time scales were obtained by orbital tuning with the assumption of arbitrary but time invariable amplitudes and phase lags of the orbital parameters and responses.
The retuned chronologies highlighted the cycles of eccentricity (100 kyr), obliquity (41 kyr), and precession (23 and 19 kyr), but the combined 70- and 30-kyr cycles became less prominent in the continental (Baikal) record though persisted in the global data (Vostok δD). The residual 70- and 30-kyr harmonics more likely result from errors in the untuned chronology for the Baikal record but are rather due to nonlinearity in the climate response.
We investigated the leads and lags of orbital climate signals with a special focus on the 100-kyr cycle. The phases of precession, obliquity, and eccentricity cycles, compared among the records, showed the lead of the continent. The Baikal geochemical signal at the 100-kyr band led the global glacial and greenhouse CH₄ responses and was almost synchronous with the earliest responding polar temperature signal. The reported results characterize the continent as a system highly responsive to eccentricity variations but do not contradict alternative hypotheses for the origin of the 100-kyr cycle in the Earth's climate history.

We examined mercury distribution in soils and plants of the catchment area of Lake Bol'shoe Yarovoe with the Altaikhimprom chemical industrial complex situated on its shore. Data on mercury contents show a considerable mercury flow into the environment, though the industrial complex and its waste do not pose serious threat. The revealed pollution in the immediate vicinity of the industrial complex, including that due to atmospheric transport, as well as the elevated content of mercury in hydrochloric and alkaline extracts suggest its intense migration from the waste. Therefore, it is necessary to make up an inventory of the industrial-complex waste and perform a detailed study of the lake ecosystem as a model unit.

The effect of local stress on the interface response to dynamic loading in faulted crust has been studied through MCA (movable cell automata) simulation. Knowing the strain response of a fault block boundary to test impacts, one can estimate the proximity of the fault to critical stress that allows an unstable slip. The computing results are consistent with data of field experiments in fault fragments (vibration, water injection, explosions). The reported analysis makes the basis for a new approach to estimating stress and strain in active faults.

Electrical resistance measurements, thin-section, chemical, thermal differential, and thermal gravity analyses have been applied to study samples of chromite and the host serpentinite from the Podenny and Kurman deposits in the Alapaevsk ophiolite and from the Piany Bor and southern deposits in the Klyuchevskoi ophiolite. Samples from the four sites exhibit similar patterns of activation energy (E₀) vs. resistance coefficient (log R₀). The E₀-log R₀ points of samples collected away from ore fields align along a straight line corresponding to the log R ₀ = a - bE₀ relationship typical of nonmineralized rocks, with the a and b coefficients as in alpine ultramafics. The samples of mineralized rocks depart from the basic line, the departure increasing as they approach the orebody. Though having similar patterns, the E₀-log R₀ fields of the samples from different sites show no overlap. The revealed features may be useful as implicit diagnostic criteria for ophiolite-hosted chromite mineralization.

Various opinions on the position of the Middle/Upper Triassic boundary have been concisely reviewed. The lower boundary of the Carnian Stage is accepted at the base of the Trachyceras aon Zone. The recentmost data on biostratigraphy of boundary beds of the Ladinian and Carnian Stages of the Southern Alps, Himalayas, British Columbia, northeastern Asia, Svalbard, and Arctic Canada have been considered and critically analyzed. Using sections of British Columbia with mixed Boreal and Tethyan fauna of Ammonoidea, we compared biostratigraphic schemes of the Middle/Upper Triassic boundary interval of the Boreal and Tethyan regions. On the basis of correlations and paleontological data, the lower boundary of the Carnian Stage in Northeastern Asia is suggested to be drawn at the base of the ammonoid

Basic and ultrabasic rocks in high- and ultrahigh-pressure collision belts can provide important petrological information. Mantle-derived and

The relative abrasive stability of kimberlite indicator minerals such as pyrope, picroilmenite, olivine, and apatite as well as diamonds and kimberlite fragments was studied experimentally, and the following sequence of mineral abrasive stability was established: pyrope-olivine-picroilmenite-apatite-kimberlite fragments. Diamond did not virtually change during the experiment. Kimberlite fragments appeared to be rather stable. Their relics were preserved until the end of the experiment, whereas the other minerals acquired wearing-resistant shapes. Pyrope, olivine, and apatite were shaped into an oval. Owing to anisotropy of microhardness, picroilmenite forms hexagonal tablets, which are typical of ancient haloes of indicator minerals in all diamondiferous regions. The parity analysis of the abrasive stabilities of pyrope and picroilmenite has shown that in the haloes of

Formation of mountains of the Central Tien Shan is usually explained by the isostatic response of the crust to its shortening caused by the India-Eurasia collision. The rise of the region in the period from Oligocene to Late Pliocene (2 myr ago) reached ~700 m on average, which corresponds to the isostatic response. For the last 2 myr (Late Pliocene-Quaternary), the rate of rise increased by an order of magnitude. This is proved by the coarsening of Cenozoic molasse up the sections, acceleration of cutting of drainage systems into ridges, and formation of new ridges within basins. In the Quaternary, most of intermontane basins underwent uplifting, though not so intense. The average rate of lateral crustal shortening increased ~2-2.5 times only, and the contribution of this process to the Late Pliocene-Quaternary orogeny was no more than 10%. The acceleration of rise was caused mainly by the convective replacement of the mantle lithosphere by the less dense asthenosphere. This was due to the quick softening of the mantle lithosphere as a result of the infiltration of active fluid from the lower mantle. Such accelerations of crustal uplifting took place in the Pliocene and Quaternary in many continental regions. This evidences that mantle processes, first of all, the full or partial replacement of the mantle lithosphere by the asthenosphere, played an important role in the formation of mountains.

We discuss the patterns of Late Cenozoic faulting and crustal stress in the northeastern flank of the Baikal rift system. The Late Cenozoic faults are mainly of NE and ENE strikes. Faults of these trends, along with W-E faults, have been principal seismogenic structures. They have normal or left-lateral oblique geometry with different amounts of horizontal motion. The N-S, NW, and NNW faults bear signature of mostly right-lateral strike slip, and those of the WNW direction are left-lateral strike-slip faults, often with a normal component. The rift basins in this part of the rift system have had different evolution dynamics, with the most rapid faulting and sedimentation in the Muya basin. According to structural and seismological data, regional stress in the area has been stable and dominated by NW extension through the Pleistocene-Holocene and the Present. The directions and obliquity angles of principal normal stresses and percentages of stress types show local lateral variations. The evolution of the northeastern flank of the Baikal rift system can be explained by a model of oblique rifting which accounts for the architecture of rift basins, the pattern of Late Cenozoic active faults, and the stress pattern derived from structural and seismicity data. The model is consistent with centrifuge models of magma emplacement during continental oblique rifting. Oblique extension associated with underplated magma can be maintained in the area by mantle plumes beneath the Kichera, Upper Angara, and Chara rift basins. The presence of subcrustal magma chambers may explain why the three basins formed before other basins in the NE flank of the rift system.