English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Hole 396B of Leg 46 of the Glomar Challenger (located at 22°59.14'N, 43°30.90'W, about 160 km east of the Mid-Atlantic Ridge) penetrated 205.5 meters into basement and encountered primarily basaltic pillow lava and fragmented material. Only one thick cooling unit was encountered. The purpose of this paper is to describe this cooling unit and discuss its petrographic, mineralogic, and chemical features in terms of its mode of emplacement and the processes occurring during its crystallization. The cooling unit is sparsely olivine and plagioclase phyric and occupies most of Core 15 (235.0 to 244.5 m sub-bottom), but because of poor recovery at both margins, neither the top nor the bottom can be identified with complete certainty. If recovery is proportional to actual thickness, the unit is about 9 meters thick. From the top of Core 15 to about 36 cm, the rock is sparsely phyric pillow basalt, which is chemically related to the cooling unit (Leg 46 Scientific Party, this volume). The top of the cooling unit may be the glassy zone at about 36 cm (Section 15-1, piece 6), but this may also be just another pillow rind. From 36 cm to 80 cm, the material recovered is fragments up to 10 cm long which cannot be fit back together. The highest piece examined is Section 15-1, piece 11 (86 cm). This piece clearly belongs to the cooling unit. From 80 cm to 600 cm recovery is almost continuous, the pieces can be fit back together well, and the textural variation can be seen clearly in hand specimen and thin section. From 600 cm to 700 cm recovery is again fragmentary, but the textural variation appears to continue. We will assume that the lowest sparsely phyric piece is the base of the cooling unit, but because of the incomplete recovery, we will simply plot data versus position in Core 15. Below 700 cm the rock is porphyritic pillow basalt chemically unrelated to the cooling unit and with a different magnetic inclination (Leg 46 Scientific Party, this volume). The contact was not recovered.

Crystallization of the Core Basalt Cooling Unit, Hole 396B, DSDP Leg 46