Archive · dataset · 1991
Grain size distribution of Oligocene and Miocene sediments from the Indus Fan
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The Owen Ridge south of Oman represents oceanic crust that was uplifted by compressional tectonic forces in the early Miocene.
Description
Build-out of the Indus Fan led to deposition of a thick sequence of turbidites over the site of the Ridge during the late Oligocene and early Miocene. Early Miocene uplift of the Ridge led to a pelagic cap of nannofossil chalks.
Two short sequences of turbidites from the pre- and syn-uplift phases were chosen for detailed grain size analysis.The upper Oligocene section at Site 731 is composed of thin (centimeter-decimeter scale) graded mud turbidites separated by relatively thick (decimeter-meter scale) intervals of homogeneous, non-bioturbated clayey siltstones. These finer intervals are unusually silt-rich (about 60%) for ungraded material and were probably deposited as undifferentiated muds from a series of turbidity current tails.
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By contrast, the lower Miocene section at Site 722 is comprised of a sequence of interbedded turbidites and hemipelagic carbonates. Sharp-based silt turbidites are overlain by burrow-mottled marly nannofossil chalks.The Oligocene sequence may have accumulated in an overbank setting on the middle fan - the local topographic position favoring frequent deposition from turbidity current tails and occasional deposition from the body of a turbidity flow.
Uplift of the Ridge in the early Miocene led to pelagic carbonate deposition interrupted only by turbidity currents capable of overcoming a topographic barrier. Further uplift eventually led to entirely pelagic carbonate deposition.
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Catalogue records · 1
- OAI-PMH record oai.datacite.org/oai?verb=GetRecord&metadataPrefix=oai_dc&identifier=doi%3A10.1… ↗
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Topics
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- Earth & Environmental Science · Ocean & Atmospheric Science
Related
- Possibly the same asGrain size distribution of Oligocene and Miocene sediments from the Indus Fan
Provenance · 1 source records, 7 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| GigaDB | doi:10.1594/pangaea.756773 | 20 h ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| access_level | source · gigadb org | connector:gigadb_org@1.0.0 | |
| concepts[field].local:field:earth-environmental | mapping · gigadb org | connector:gigadb_org@1.0.0 | |
| concepts[field].local:field:ocean-atmospheric | mapping · gigadb org | connector:gigadb_org@1.0.0 | |
| description | source · gigadb org | connector:gigadb_org@1.0.0 | /metadata/dc/description |
| license | source · gigadb org | connector:gigadb_org@1.0.0 | /metadata/dc/rights |
| publication_date | source · gigadb org | connector:gigadb_org@1.0.0 | |
| title | source · gigadb org | connector:gigadb_org@1.0.0 | /metadata/dc/title |