A sonic well log of the basement complex of the Walvis Ridge

A sonic well log was obtained within the basement complex of the Walvis Ridge during Deep Sea Drilling Project Leg 74. The top of the basement complex is characterized by smooth acoustic reflectors. The rocks recovered within the basement complex consist of basalts with intercalated sediments. According to the log ～-50% of the upper 75 m of basement are igneous rocks and the other 50% sedimentary. Sonobuoy results indicate that the ratio of sediments to basalt increases with depth for an additional 225 m until a typical oceanic velocity structure is observed. Paleontological results suggest that the processes forming this upper 300 m of the basement complex was accomplished within a short time interval.     

Asia–Europe–United States: the geoeconomics of uncertainty

This paper examines a key aspect of how the global geometries of finance and trade articulate the euro–dollar relationship. Here, European integration extends into a global financial and trading system replete with contradictions. The paper examines these, drawing upon a literature from international political economy, foregrounding the spatialities that they signal.     

ANALYTICAL AERIAL TRIANGULATION BLOCK ADJUSTMENT; THE DIRECT HEIGHT SOLUTION INCORPORATING TIE-STRIPS

The historical development of analytical aerial triangulation block adjustment is mentioned by way of introduction. The advantages of separating the plan and height adjustments are given and the observation equations of a typical adjustment section are analysed to show that this convenient practice is justified in normal circumstances. The principles of a direct solution of the normal equations suitable for a moderate-sized computer, are explained and developed in detail for the height adjustment. The advantages of tie-strips in the height adjustment are demonstrated and the difficulties which then arise are discussed. An approximate method which overcomes these difficulties is developed. Details of the computer programmes used are given in Appendix B.     

Diatoms and aquatic palynomorphs in surface sediments of the White Sea bays as indicators of sedimentation in marginal filters of rivers

Diatom algae, aquatic palynomorphs, and the grain-size of surface sediments from bays of the White Sea were investigated in a program dedicated to the study of marginal filters (MF) in the Severnaya Dvina, Onega, and Kem rivers. Three microalgal assemblages are established in surface sediments, which replace each other successively with distance from river mouths and are characterized by a gradual decrease in a share of freshwater species of diatoms and Chlorophyceae algae, significantly varying concentrations of marine diatoms and dinocysts due to changes in water salinity, grain-size composition of sediments, quantitative distribution of suspended particulate matter (SPM), and water productivity at different marginal filter stages.     

Recognition of the Cambrian Timan–Severnaya Zemlya orogen and timing of geological evolution of the North Kara sedimentary basin based on detrital zircon dating

New data on the ages of detrital zircons from folded basement rocks and cover sediments of the Severnaya Zemlya archipelago and Izvestiy TSIK islands have been obtained. The basement age is defined as Cambrian (pre-Ordovician). The Ordovician and Silurian sandstones were mainly formed by erosion of the basement rocks. The Devonian sandstones were formed by debris sourced from the Caledonian orogen. The Carboniferous–Early Permian molasse was formed simultaneously with the erosion of the Carboniferous granitoids and weathering of the Ordovician volcanic arc rocks and the Cambrian basement. The North Kara basin was formed in the Ordovician as a back-arc basin. It experienced its main compression deformations at the boundary of the Devonian and Carboniferous and in the Carboniferous.     

An autochthonous Avalonian basement source for the latest Ordovician Brenton Pluton in the Meguma terrane of Nova Scotia: U–Pb–Hf isotopic constraints and paleogeographic implications

International Journal of Earth Sciences - The Ediacaran–Ordovician Meguma Supergroup was thrust over Avalonia basement prior to the intrusion of post-Acadian, ca. 370 Ma, S-type...     

The likelihood of having a household emergency plan: understanding factors in the US context

Natural Hazards - Individual household emergency planning is the most fundamental and can be the least expensive way to prepare for natural disasters. However, despite government and nonprofit...     

The evolution of slump-induced destruction of Kukuy Griva slope (Lake Baikal) revealed on the base of the data of seismic and acoustic surveys

As a result of careful interpretation of the data of recent seismo-acoustic surveys, two major seismic complexes were identified in the structure of the upper sedimentary section of the north-western slope of Kukuy Griva (ridge). They are composed of several inner seismo-facies, which are very characteristic and separated with well-expressed regional reflector. Seismic and acoustic data revealed evidences of numerous landslide processes which were different in age and peculiarities of manifestation. For the first time, detailed schemes of seismo-facies distribution are compiled for major seismic complexes at the area. The boundary between seismic complexes is dated as 150 thousands years. It is shown that sliding was more intensive during Late Pleistocene and Holocene, reflecting activation of tectonic movements in this part of Baikal rift system.