Browsing by Author "Schmincke, H.-U."
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Mantle heterogeneity in the North Atlantic : evidence from oceanic islandsPublication . Schmincke, H.-U.; Staudigel, H.; Brey, G.Geochemical domains in the North Atlantic have been based upon major element composition of island basalts such as the K/Na-ratio with potassic islands such as São Miguel (Azores) distinguished from highly sodic provinces (Madeira group) (Schmincke, 1973): - ocean floor basalt glasses from the Mid-Atlantic Ridge with Ti-rich and K-poor provinces, south of ca. 32° N, distinguished from areas richer in K (north of ca. 32° N) (Melson, Dimitriev, 1979); - highly incompatible elements such as Th and La which show characteristic ratios for several ocean floor provinces in the northern North Atlantic (Tarney, Treuil, Wood, 1979). […].
- Submarine pyroclastic rocks of the La Palma «Ophiolite» complexPublication . Staudigel, S.; Schmincke, H.-U.The basement of La Palma (Canary Islands) consists of plutonic and hypabyssal intrusive and a submarine series, 2.5 km thick. Pyroclastic rocks increase in thickness upwards in the section and dominate at the top where they are several 100 meters thick. The clastic rocks in the pillow-dominated section are well bedded to cross-bedded hyaloclastites forming layers generally < 2 m thick, and thicker beds (up to 5 m) of coarse breccias which range from incipiently fractured pillows, that came to rest nearly in situ, to coarse, well sorted breccias deposited some distance from their source. Clastic rocks in the upper section are massive to poorly bedded, dominantly lapilli- to sand-sized whit clasts, being generally highly vesicular and larger fragments being reddish oxidized displaying shapes and vesicularity intermediate between pillows and sub-aerial scoria. […].