کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4718907 | 1639151 | 2010 | 10 صفحه PDF | دانلود رایگان |
St Peter and St Paul Rocks (SPSPR) are emergent portions of a peridotitic mass within the St Paul fracture zone of the Equatorial Mid-Atlantic Ridge, where local seismicity is dominated by strike-slip mechanisms. We used subtidal red algae in living position, death assemblages in intertidal conglomerates, and marine terraces as sea-level markers. The highest deposits correspond to a marine terrace with a shoreline angle at 8 ± 1 m asl that formed ca. 6400–6200 cal. yr BP. After correction for the sea-level changes derived by glacioisostatic modelling, AMS and radiometric 14C age measurements on the Holocene sea-level markers indicate emergence during the last 6600 a at a minimum average rate of ∼ 1.5 mm/a. We propose that uplift resulted from peridotite emplacement by extrusion, rather than volcanic activity or fault slip, with the implication that the ridge has been subject to compression during the Holocene.
Journal: Marine Geology - Volume 271, Issues 1–2, 15 May 2010, Pages 177–186