Consolidation properties and structural alteration of Old Alluvium

Acta Geotechnica - We present experimental observations and a conceptual model for understanding the compression and swelling characteristics of Old Alluvium (OA) from San Juan, Puerto Rico. Prior...     

An apparent magmatic cycle in the Tasman geosyncline

The igneous events of two geosynclines within the N.S.W. portion of the Tasman Orthogeosyncline are compared, not according to the actual ages of the igneous rocks, but on the basis of their position with respect to the development of the geosyncline. Thus, Cambrian volcanic rocks in one depositional area are compared with Lower Devonian in the other, Ordovician and Silurian with Middle Devonian‐Lower Carboniferous, and Devonian with Permian. Intrusive rocks are fitted into this scheme, and their ages discussed. Such a comparison reveals an apparent igneous cycle, and speculations on the cause of such a cycle are outlined.     

Water Materialities and Citizen Engagement: Testing the Implications of Water Access and Quality for Community Engagement in Ghana and South Africa

We analyze the relationship between perceptions of domestic water access, and quality, in relation community engagement. While others have suggested linkages between material conditions of water access and engagement (e.g., that poor water access might spur engagement), to date there have been no studies those test these relationships using statistical methods. Based on a quantitative analysis of survey data from underserved sites in Accra, Ghana, and Cape Town, South Africa, our results show that water access and quality are both predictive of community engagement. The analysis also makes a strong case that there are different dimensions when considering the material conditions of water—in this case, water access and quality each condition engagement in opposite directions. Furthermore, consistent with other studies, our study also shows different demographics (notably gender) mediate these relationships in important ways.     

Magnetic anisotropy and fabric of some foliated rocks from S.E. Australia

Summary The magnetic anisotropy of foliated rocks of several types has been measured by the torque-meter method, and shows that the alignment of long axes of magnetic grains in rocks normally follows the pattern of foliation evident in field observations. In a sharp fold in a lit-par-lit formation the magnetic anisotropy indicated an otherwise undetected lineation independent of the bedding and superimposed upon the foliation determined by the layering. In two adamellites, each with two alignment patterns separated by an angle of 30° the magnetic data are shown to be consistent with two foliations but not with one foliation plus a lineation. Magnetic anisotropy data can be ambiguous for rocks in which two or more grain alignment processes have operated, but combined with other observations magnetic measurements can provide a valuable new tool in the study of rock fabrics.     

Metamorphic and metasomatic convergence of basic igneous rocks and lime‐magnesia sediments of the precambrian of North‐western Queensland∗

With increasing intensity of metamorphism, and particularly metasomatism, it becomes more and more difficult to separate amphibolites in North‐western Queensland into ortho‐ and para‐amphibolites, and a stage is reached at which the two are indistinguishable. Field evidence, carefully sought, has enabled the origin of some apparently identical rocks to be determined, and laboratory methods were applied to these rocks to see if grounds for the separation of amphibolites of unknown origin could be determined. None of the six methods tried — mineralogy (including feldspar twinning), chemical analysis (including TiO2 content), spectrography, rock magnetism — proved to be as successful as the field method in distinguishing the two rock groups; some methods used with apparent success elsewhere, such as feldspar twinning or chemical analyses, are found to be unsuccessful here, which suggests that though the problem is world‐wide, solutions are only of local validity.     

The form of the intrusive complex at mount dromedary,New South Wales

In the past the Mount Dromedary igneous complex has been regarded as a differentiated laccolith, with the more felsic banatite at the summit of the mountain, monzonite on the lower slopes and pyroxenite at sea‐level.

Evidence is put forward to show that this is not the case and that the form is that of a stock or ring‐dyke with very steep contacts.

The monzonite has been emplaced by forceful injection and the banatite by permissive emplacement along a vertical, cylindrical fracture in the monzonite. The pyroxenite may form a separate dyke or stock.     

Chromospheric synoptic charts for the solar eclipse of November 3, 1994

The synoptic charts of the filaments and active regions near the solar limb are given for the eclipse of November 3, 1994, along with the positions of the prominences. A table helps to associate coronal and chromospheric structures.