a research program was conducted on different clay-bearing rocks selected from the ilam, sarpol-e zahab and tajarak regions (iran) to predict their slaking characteristics. the new durability apparatus (nested mesh drums) separates disintegrated particles varying from > 25.4 to < 2 mm as the drums were rotated. on the basis of the particle size distribution, the disintegration ratio (dr) was us...

the study area is located in the northeast of iran. miankuhi formation is 500m thick and comprises homogeneous shales, brown granular sandstone and siltstone. in this study, 45 samples were taken from miankuhi shales and sandstones in order to determine their tectonic origin by using a polarizing microscope. samples were analysed by x-ray fluorescence (xrf) method to determine their chemical co...

voluminous quaternary extrusive rocks, associated with widespread volcanic activities, occur in the northwestern iran and across the turkish-iranian plateau. field and petrographic studies reveal that these volcanic rocks, consisting of basalt to trachyandesite, occur as lava flows, columnar basalts, and cinder cones in three distinct areas of northern (bazergan-maku-burlan), middle (chalderan)...

Field mapping and geochronologic and thermobarometric analyses of the Gurla Mandhata area, in southwest Tibet, reveal major middle to late Miocene, east-west extension along a normal-fault system, termed the Gurla Mandhata detachment system. The maximum fault slip occurs along a pair of low-angle normal faults that have caused significant tectonic denudation of the Tethyan Sedimentary Sequence,...

The high-grade uranium deposits in the Xiemisitan area, northwestern China, are genetically associated with the faulting of felsic volcanic or sub-volcanic rocks. Ferric iron alteration indicates that oxidizing hydrothermal fluids percolated through the rocks. In this study, we measured the gamma-ray intensities of rocks in the Xiemisitan area and we propose a hybrid method for the mapping of f...

Given a finite point set P ⊂ R, we call a multiset A a one-sided weak ε-approximant for P (with respect to convex sets), if |P ∩ C|/|P | − |A ∩C|/|A| ≤ ε for every convex set C. We show that, in contrast with the usual (two-sided) weak ε-approximants, for every set P ⊂ R there exists a one-sided weak ε-approximant of size bounded by a function of ε and d.

There is an intangible quality of implausibility to Australia that is impossible to put into words. It has an ancient and fragile feel: it is almost a continental equivalent of a tree sprouting out of a seemingly solid rock; precarious and beautiful and not quite sustainable. It is a continent where the unexpected is usual, and yet it is always surprising and thrilling when the unexpected is fo...

Selective oviposition can have important consequences for recruitment limitation and population dynamics of organisms with complex life cycles. Temporal and spatial variation in oviposition may be driven by environmental or behavioral constraints. The goals of this study were to: (1) develop an empirical model of the substrate characteristics that best explain observed patterns of oviposition b...

The 10.5 km diameter Bosumtwi crater in Ghana, West Africa, is the most likely source crater for the Ivory Coast tektites, as the tektites and the crater have the same age (1.07 Ma), and there are close similarities between the isotopic and chemical compositions of the tektites and crater rocks. The crater is excavated in 2.1–2.2 Ga old metasediments and metavolcanics of the Birimian Supergroup...

This paper provides the background to the 50th Rankine Lecture. It considers the growth in emphasis of the prediction of ground displacements during design in the past two decades of the 20th century, as a result of the lessons learnt from field observations. The historical development of the theory of elasticity is then described, as are the constitutive frameworks within which it has been pro...