Siliceous sedimentary rocks of Tertiary age were recovered at three of the nine sites drilled during Leg 31 (Table 1). Only relatively small amounts of lithified material were retrieved, but these rocks are particularly interesting because they include three distinct types of siliceous rock and because each type occurs with a distinct sediment lithology. The kinds of rocks sampled are (with lit...

In this paper we classify the range of feldspathic igneous rocks using five geochemical variables: the FeO/(FeOþMgO) ratio or Fe-index, the modified alkali^lime index, the aluminum-saturation index, the alkalinity index, and the feldspathoid silica-saturation index.The Fe-index distinguishes between melts that have undergone extensive iron enrichment during differentiation from those that have ...

The linear discrepancy of a poset P is the least k such that there is a linear extension L of P such that if x and y are incomparable, then |hL(x)− hL(y)| ≤ k. Whereas the weak discrepancy is the least k such that there is a weak extension W of P such that if x and y are incomparable, then |hW (x)− hW (y)| ≤ k. This paper resolves a question of Tanenbaum, Trenk, and Fishburn on characterizing w...

________________________________________ Introduction __ ___________________________________ Area covered.__________________________________ Aeromagnetic survey.___________________________ Gravity survey.________________________________ Acknowledgments--.. __1________________________ Geology __ __ ____________ _ Rock units_____________________________________ Carboniferous and older rocks._____...

the cheshin meta-calcareous rocks (permo triassic) in southeast hamedan outcrop in association with a variety of pelitic schists and hornfels rocks. the intrusion of the alvand batholith (jurassic age) into pelitic and calcareous host rocks has produced metamorphic rocks in the hamedan area (cheshin village). on the basis of the dominance of calcite/dolomite, silicate and ore minerals, the calc...

During underground nuclear tests, rocks may fail by plastic yielding, which limits shear strength, or by tensile fracture, wherever maximum principal stress exceeds tensile strength. A third mode of failure exists due to friction along closed fractured surfaces. There, friction affects slipping and can thus limit stress. In this paper, we study the effect of friction on the simulated dynamic re...

Folding is a common mode of deformation in geology when mechanically layered rocks are subjected to compression. They occur on a wide range of scales from mm-scale to 10’s of kilometers in places where upper crustal rocks are compressed as a result of tectonic plate convergence (such as in the Zagros mountains, Iran). The physical instability that results in the formation of folds has been stud...

There is a great need for more precise absolute ages for sedimentary rocks. We have been actively involved in developing techniques to directly date sedimentary rocks, rather than using associated igneous rocks, or using relative dating techniques. Sedimentary phosphate nodules (i.e. coprolites) are ideal candidates for absolute dating of sedimentary rocks. Phosphates occur commonly within the ...

introduction the area reviewed and studied in this paper is located 5 km southeast of sarbisheh city at eastern border of the lut block (jung et al., 1983; karimpour et al., 2011; richards et al., 2012) in eastern iran between 59° 47′ and 59° 53′ e longitude and 32°30′ and 32°34′ n latitude. the magmatic activity in the lut block began in middle jurassic (165-162 ma) and reached its peak in ter...

This thesis compiles two distinct studies that both document the control of microstructures on rock seismic properties. The first part deals with the development of crystallographic preferred orientations (CPO) in the uppermost mantle associated with melt/fluid-rock interactions, recorded in peridotites xenoliths from the Japan sea back-arc basin. The microstructural and geochemical characteris...