← Search

Archive · collection · 1995

Mean grain size and structure of ODP Hole 140-504B samples

Listed in PANGAEA

Microstructural investigations of ocean crust samples provide a complementary approach to both marine surveys and laboratory experiments.

Description

The recovery of relatively undeformed diabases from Deep Sea Drilling Project (DSDP)/Ocean Drilling Program (ODP) Hole 504B provides a first opportunity to examine a reference section of microstructural features that influence strain localization at depths of 2 km in the ocean crust.

Syn- and post-crystallization features in plagioclase and augite crystals have been examined by optical microscopy and secondary and backscattered electron imaging. These features show a strong influence of modal composition and primary textures on early sites of strain localization. Thermal cracking and subsequent alteration intensities and distribution are strongly phase dependent.

Read the rest (2 more)

A consistently higher intragranular fracture density is observed in augite crystals relative to plagioclase. The impact of alteration on the mechanical response of diabases is likely to depend on the primary textural characteristics. Even where extensive augite alteration occurs, the rock remains supported by a framework of weakly altered plagioclase crystals.

The Hole 504B diabases from Leg 140 provide a valuable comparison for future studies of more deformed sections likely to be encountered at depth. Advances in constraining the detailed rheology of the ocean crust at spreading centers would benefit from experimental deformation of texturally diverse diabase and gabbro samples.

Links

Where it is published

Catalogue records · 1

Topics

Inferred from text
Geology 68% · Imaging 75% · Microscopy 75%
Provenance · 1 source records, 10 field assertions
SourceKeyLast seenRaw
PANGAEAoai:pangaea.de:doi:10.1594/PANGAEA.80668714 d agoJSON v1
FieldAssertionExtractorEvidence
access_levelsource · PANGAEAconnector:pangaea@1.0.0
concepts[field].anzsrc:group:3705enrichment · PANGAEAtaxonomy-embedding@1.1.0title+keywords+description (68%)
concepts[field].local:field:earth-environmentalmapping · PANGAEAconnector:pangaea@1.0.0
concepts[modality].local:modality:imagingenrichment · PANGAEAkeyword-concept-rules@1.0.0title+description (75%)
concepts[modality].local:modality:microscopyenrichment · PANGAEAkeyword-concept-rules@1.0.0title+description (75%)
descriptionsource · PANGAEAconnector:pangaea@1.0.0/metadata/dc/description
licensesource · PANGAEAconnector:pangaea@1.0.0/metadata/dc/rights
publication_datesource · PANGAEAconnector:pangaea@1.0.0
spatialsource · PANGAEAconnector:pangaea@1.0.0
titlesource · PANGAEAconnector:pangaea@1.0.0/metadata/dc/title