Nonmarine Cretaceous palynology of northern Kordofan,Sudan, with notes on fossil Salviniales (water ferns)

A palynological investigation of 164 samples from 18 water wells in northern Kordofan, Sudan, enabled the recognition of five informal zones based on pollen and spore assemblages ranging in age from Albian to Maastrichtian. The youngest (late Campanian-Maastrichtian) assemblages are restricted to the Bagbag Basin, whereas Albian-Cenomanian (to Turonian) sediments are widespread to the east and west of the Bagbag area. Impressions of Salvinia floating leaves from outcrops of the upper Hamrat el Wuz Formation, western part of the study area, are among the oldest occurrences of this water fern and indicate a Campanian-Maastrichtian age for these sediments.The vertical distribution of hygrophilous (pteridophytic spores) versus xerophilous (ephedroids and possibly small, weakly sculptured tricolporates) elements in the palynofloras suggests widespread moist or even aquatic habitats in the Albian-Cenomanian and Campanian-Maastrichtian. A shift towards drier conditions occurred in the late Cenomanian-Turonian. Throughout the Cretaceous, however, there may have been extensive arid/semiarid areas of non-deposition and seasonally dry periods. Some characteristics of the local palynofloras are attributed to its inner continental position. Rare Albian-Cenomanian and Campanian-Maastrichtian dinoflagellates could be interpreted as lacustrine phytoplankton rather than as evidence for marine influence.     

A new approach to the automatic computation of partial volumes of river runoff with various degrees of pollution (a case study for the Selenga River)

Proposed are the methods and software package that enable estimating automatically the degree of the pollution of annual and long-term river runoff at the joint processing of large volumes of standard (routine) hydrological and hydrochemical information. As a result of computations, the individual quality certificate of river runoff was created for the part of the river under study. Computation methods include regulations concerning the parameters that connect the water runoff volume with water quality; the parameters that may connect the computation of the pollution degree using RD 52.24.643-2002 adapted for the partial volumes of the annual runoff according to these methods, with the subsequent classification of the pollution degree. The computation technique was worked out and used for the first time. The informativeness of estimates is demonstrated for one of the discharge section lines of the Selenga River.     

The effects of the target material properties and layering on the crater chronology: The case of Raditladi and Rachmaninoff basins on Mercury

In this paper we present a crater age determination of several terrains associated with the Raditladi and Rachmaninoff basins. These basins were discovered during the first and third MESSENGER flybys of Mercury, respectively. One of the most interesting features of both basins is their relatively fresh appearance. The young age of both basins is confirmed by our analysis on the basis of age determination via crater chronology. The derived Rachmaninoff and Raditladi basin model ages are about 3.6 Ga and 1.1 Ga, respectively. Moreover, we also constrain the age of the smooth plains within the basins' floors. This analysis shows that Mercury had volcanic activity until recent time, possibly to about 1 Ga or less. We find that some of the crater size-frequency distributions investigated suggest the presence of a layered target. Therefore, within this work we address the importance of considering terrain parameters, as geo-mechanical properties and layering, into the process of age determination. We also comment on the likelihood of the availability of impactors able to form basins with the sizes of Rachmaninoff and Raditladi in relatively recent times.     

Variograms with zonal anisotropies and noninvertible kriging systems

Zonal anisotropies are usually simply defined as those that are not geometric (i.e., that cannot be removed by an affine transformation). Such anisotropies have often been associated with zonations and models have been proposed to reflect that association. It is shown by example that such models can lead to noninvertible coefficient matrices in kriging systems, because the models are only (conditionally) semidefinite instead of positive definite. The relationship to the construction used in turning bands algorithm and also to spatial-temporal models is discussed.     

Seismicity and isostasy

Both a theoretical treatment and observed data show that the isostatic gravity field and the seismicity are closely related. The equation for harmonic loading shows that large deviations from isostatic equilibrium lead to large shear stresses in the crust. High seismic activity correlates well with large isostatic gravity anomalies and with large horizontal gradients of isostatic gravity anomalies. Studies of seismicity should consider the isostatic gravity field.     

Shock Wave Effects from the Impacts of Cosmic Objects with Diameters from 20 m to 3 km

Izvestiya, Physics of the Solid Earth - Abstract—Destruction on the Earth’s surface caused by a shock wave is one of the most important and dangerous effects from asteroid and comet...     

On the accuracy of initial seismological data in the problem of seismic hazard assessment

The parameters of the September 3, 1978, earthquake in the Western Caucasus are presented according to data from different seismological agencies. This event, along with the 1966 earthquake in Anapa, is the strongest seismic event in the region. The solutions suggested in the main international and national seismological agencies contradict the well-known fact that the earthquake did not have catastrophic consequences. This is confirmed only by the position of the epicenter according to GCMT data intended for determining somewhat different earthquake parameters: the focal mechanism and seismic moment. Despite the fact that there was no expedition to perform a macroseismic study of the earthquake, some information was collected by phone survey. Information on the spatial distribution of the macroseismic effect made it possible to more accurately determine the epicenter position according to the GCMT data.     

Sources of SEP Acceleration during a Flare – CME Event

A high-speed, halo-type coronal mass ejection (CME), associated with a GOES M4.6 soft X-ray flare in NOAA AR 0180 at S12W29 and an EIT wave and dimming, occurred on 9 November 2002. A complex radio event was observed during the same period. It included narrow-band fluctuations and frequency-drifting features in the metric wavelength range, type III burst groups at metric – hectometric wavelengths, and an interplanetary type II radio burst, which was visible in the dynamic radio spectrum below 14 MHz. To study the association of the recorded solar energetic particle (SEP) populations with the propagating CME and flaring, we perform a multi-wavelength analysis using radio spectral and imaging observations combined with white-light, EUV, hard X-ray, and magnetogram data. Velocity dispersion analysis of the particle distributions (SOHO and Wind in situ observations) provides estimates for the release times of electrons and protons. Our analysis indicates that proton acceleration was delayed compared to the electrons. The dynamics of the interplanetary type II burst identify the burst source as a bow shock created by the fast CME. The type III burst groups, with start times close to the estimated electron-release times, trace electron beams travelling along open field lines into the interplanetary space. The type III bursts seem to encounter a steep density gradient as they overtake the type II shock front, resulting in an abrupt change in the frequency drift rate of the type III burst emission. Our study presents evidence in support of a scenario in which electrons are accelerated low in the corona behind the CME shock front, while protons are accelerated later, possibly at the CME bow shock high in the corona.     

Halite oolites and ripples in the Dead Sea, Israel

Clastic features in recent halite deposits are observed along the beaches of an artificially dammed part of the Dead Sea. These features include halite oolites (termed halolites in this paper) and ripples. Halite precipitates initially either at the brine surface or on the floor. It is suggested that moderate increase of wave agitation shifts the balance towards brine-surface crystallization, and keeps the growing halite grains in constant motion. In this way rippled structures are formed. A further increase of wave energy leads to the growth of coated halite grains. The accumulation of the various halite grains along the beach, to form soft rippled floor and oolitic beach ridge is brought about during shoreward winds. During calm periods the bulk of the halite crystallizes directly on the floor. It develops into a hard crust which assumes the morphology of the substrate, including the ripple forms.     

Valuing the non-CO2 climate impacts of aviation

The non-CO₂ climate impact of aviation (NO_x and contrails) is assessed and emissions weighting factors (EWFs) i.e., the factor by which aviation CO₂ emissions should be multiplied to get the CO₂-equivalent emissions for annual fleet average conditions are estimated. The EWFs are estimated using two economic metrics. One is based on the relative damage cost between non-CO₂ forcers and CO₂. The other is based on the cost-effective valuation between the non-CO₂ forcers and CO₂ given an upper ceiling on the global annual average surface temperature (set at 2?K above pre-industrial levels). We also estimate EWFs using three physical metrics, Global Warming Potential (GWP), Global Temperature change Potential (GTP) and Sustained GTP (SGTP) and compare our results with the economics based metrics. Given best estimates on the forcing contributions from CO₂, contrails and NO_x from aviation and by using a discount rate of 3%/year, the RDC based metric gives an EWF equal to 1.4 (slightly higher than EWFs based on GWP and SGTP using a 100?year time horizon). EWF using the cost-effective approach depends on the time that remains before stabilization occurs. It is roughly equal to unity until a few years before the temperature reaches its ceiling, and approximately 2 when stabilization has taken place. EWFs based on GTP resemble those based on CETO when the time left to when stabilization occurs is sufficiently large. Once stabilization has occurred CETO values resemble RDC based values. If aviation-induced cirrus clouds are included, uncertainties increase and the EWFs for GWP, SGTP and RDC based metrics end up in the range 1.3–2.9, while EWFs for GTP and CETO remain close to unity in the near term.