First finds of Late Tithonian and middle-late Albian radiolarian assemblages in volcanogenic-siliceous rocks of the Amur River right lower reaches and their tectonic significance

The lithological-stratigraphic study of volcanogenic-siliceous rocks developed on the left side of the Machtovaya River, a right tributary of the Amur River, yielded the first radiolarian assemblages of the late Late Tithonian, the late Late Tithonian-early Valanginian, and the middle-late Albian age. It is established that the stratigraphic succession of volcanogenic-siliceous rocks in this area is composed of upper Tithonian-Valanginian dark red to red-brown cherts with basalts in the lower part of the section and Albian dark gray clayey cherts, olive-gray siliceous-tuffaceous argillites, and tufaceous siltstones in its upper part. The replacement of cherts by their clayey varieties likely occurred in the Aptian. The composition, structure, and age of these strata and the rocks constituting the Kiselevka-Manoma accretionary complex are different, which indicates their different tectonic origin.     

A komatiite component in Apollo 16 highland breccias: implications for the nickel-cobalt systematics and bulk composition of the moon

The lunar crust at the Apollo 16 landing site contains substantial amounts of a “primitive component” in which the ferromagnesian group of elements is concentrated. The composition of this component can be retrieved via an analysis of mixing relationships displayed by lunar breccias. It is found to be a komatiite which is compositionally similar to terrestrial komatiites both in major and minor elements. The komatiite component of the lunar crust is believed to have formed by extensive degrees of melting of the lunar interior at depths greater than were involved in the formation of the lunar magma ocean which was parental to the crust. After formation of the anorthositic crust, it was invaded by extensive flows and intrusions of komatiite magma from these deeper source regions. The komatiites became intimately mixed with the anorthosite by intensive meteoroid impacts about 4.5 b.y. ago, thereby accounting for the observed mixing relationships displayed by the crust. The compositional similarity between lunar and terrestrial komatiites strongly implies a corresponding similarity between the compositions of their source regions in the lunar interior and the Earth's upper mantle. The composition of the lunar interior can be modelled more specifically by combining the komatiite composition with its liquidus olivine composition (as determined experimentally) in proportions chosen so as to produce a cosmochemically acceptable range of Mg/Si ratios for the bulk Moon. Except for higher FeO and lower Na₂O, the range of compositions thereby obtained for the bulk moon is very similar to the composition of the Earth's upper mantle.The effects of meteoritic contamination on the abundances of cobalt and nickel in lunar highland breccias were subtracted on the assumption that the contaminating projectiles were chondritic. The cobalt and nickel residuals thereby obtained were found to correlate strongly with the (Mg + Fe) content of the breccias, demonstrating that the Co and Ni are associated with the ferromagnesian component of the breccias and are genuinely indigenous to the Moon. The lunar highland Co and Ni residuals also display striking Ni/Co versus Ni correlations which follow a similar trend to those displayed by terrestrial basalts, picrites and komatiites. The lunar trends provide further decisive evidence of the indigenous nature of the Co and Ni residuals and suggest the operation of extensive fractionation controlled by olivine-liquid equilibria in producing the primitive component of the lunar breccias. Indigenous nickel abundances at the Apollo 14, 15 and 17 sites are much lower than at the Apollo 16 site, although rocks from all sites follow the same Ni/Co versus Ni trends. It is suggested that the primitive component at the Apollo 14, 15 and 17 sites was generally of basaltic composition, in contrast to the komatiitic nature of the Apollo 16 primitive component.     

On the Use of Computational Fluid Dynamics to Investigate Aerosol Dispersion in an Industrial Environment: A Case Study

Aerosol dispersion in the area surrounding an existing biological treatment facility is investigated using large-eddy simulation, with the objective to investigate the applicability of computational fluid dynamics to complex real-life problems. The aerosol sources consist of two large aeration ponds that slowly diffuse aerosols into the atmosphere. These sources are modelled as dilute concentrations of a non-buoyant non-reacting pollutant diffusing from two horizontal surfaces. The time frame of the aerosol release is restricted to the order of minutes, justifying a statistically steady inlet boundary condition. The numerical results are compared to wind-tunnel experiments for validation. The wind-tunnel flow characteristics resemble neutral atmospheric conditions with a Reynolds number, based on the boundary-layer thickness, of Re _δ ≈ 2 × 10⁵. The numerical inflow conditions are based upon the wind-tunnel flow field. The predicted decay of both the mean and root-mean-square concentrations are in good agreement with experimental data; at 3 m from the ground, the plume mean concentration 200 m downwind of the source is approximately 2% of the source strength. The numerical data in the near-surface layer (0–50 m from the ground) correspond particularly well with the wind-tunnel data. Tentative deposition simulations suggest that there seems to be little difference in the deposition rates of large (1.8 × 10⁻⁵ m) and small (3 × 10⁻⁶ m) particles in the near-field under the flow conditions considered.     

Palaeomagnetism of upper cretaceous volcanic rocks in Sicily

From Upper Cretaceous volcanic rocks of Southeast Sicily 107 cores from 19 sites were collected giving a mean palaeomagnetic pole position at 62°N, 223°E, A₉₅ = 5.4° after AF-cleaning. This pole agrees with the Upper Cretaceous pole of Northern Africa indicating that no large post-Cretaceous relative motion has occurred between Africa and Sicily.     

Modified 3D Model of a Facular KNOT

Geomagnetism and Aeronomy - The paper presents a modified version of a previously published 3D model of the solar facular knot (Solov’ev and Kirichek, 2019), which successfully describes the...     

Deep dynamical processes in the central-southern Qinghai-Tibet Plateau—Receiver functions and travel-time residuals analysis of north Hi-Climb

Teleseismic receiver functions and travel-time residuals along the north Hi-Climb broadband seismic array in the central-southern Qinghai-Tibet Plateau show that the lithosphere structures in the central and western Qinghai-Tibet Plateau are different. In the central Qinghai-Tibet Plateau, the Indian Plate is northward subducted beneath the Qiangtang block and arrives at the greatest depth beneath the central-southern Qiangtang block. The delaminated Indian lithospheric slab remains beneath the central Lhasa block to a depth possibly greater than that of the upper interface of the mantle transform zone. In the western Qinghai-Tibet Plateau, the Indian lithospheric plate is gently northward subducted and may have arrived to the south of Tarim plate. Due to the resistance from the gently northward subduction of the Indian mantle lithosphere in the western Qinghai-Tibet Plateau, the upwelling mantle material be-neath the Qiangtang block moves mostly toward the east to bring about the lateral eastward flow of the deep mantle hot material in the central Qinghai-Tibet Plateau.     

Details of magnetic polarity transitions recorded in a high deposition rate deep-sea core

Concentrations of the (n, γ)-produced radionuclide⁶⁰Co were measured in lunar samples at various depths from the surface down to 360 g/cm². By comparing the data obtained to calculated production rates (based on the work of Lingenfelter et al. [8]) we determined the present day lunar neutron production rate, which was found to be (12 ± 3)neutrons/cm²sec (E < 10MeV).     

The Concept of a Multi-Functional Astronomy Complex and Dynamically Integrated Database Applied to Multi-Channel Observations with the MASTER Global Network

Astronomy Reports - The concept of a multi-functional astronomical complex as applied to robotic astronomy networks and systems is formulated. The practical realization of this concept in the...