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New technique for dating igneous sills

James Trude, Joe Cartwright, Richard J. Davies and John Smallwood
New technique for dating igneous sills
Geology (Boulder) (September 2003) 31 (9): 813-816


Three-dimensional seismic interpretation of Tertiary sills within the northeast Atlantic margin demonstrates that shallow-level (<1 km) intrusion of igneous sills below the seafloor can deform the interface between water and sediment during its early burial stage by hydraulic elevation of the overburden. We show that a group of interconnected sills forcibly "jacked up" the seafloor, contributing to the creation of a minibasin 5 km wide, 250 m deep, and >20 km long. The fill of the minibasin is dated biostratigraphically as 54.6-55 Ma, which fits well with radiometric dates for the timing of intrusion of sills around this basin (ca. 53-55 Ma). The recognition and dating of onlap-fill seismic reflector packages that are delimited by forced folds form a new and useful method for dating shallow-level igneous intrusions in sedimentary basins, a method that provides independent constraints on radiometric dating techniques. Similar forced folds are recognized from other basins that have shallow-level sills, suggesting that the technique presented here may be similarly applicable in comparable geologic settings.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 31
Serial Issue: 9
Title: New technique for dating igneous sills
Affiliation: Cardiff University, School of Earth, Ocean, and Planetary Sciences, Cardiff, United Kingdom
Pages: 813-816
Published: 200309
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 26
Accession Number: 2003-063132
Categories: Igneous and metamorphic petrologyStratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., sketch maps
N51°30'00" - N51°49'60", W02°19'60" - W01°53'60"
Secondary Affiliation: Amerada Hess, GBR, United Kingdom
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 200320
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