Search results for "Intraplate earthquake"
showing 7 items of 7 documents
Late Hercynian Plate and Intraplate Processes within Europe
1987
The Hercynian orogenic belt of Europe consists of a central crystalline ridge which is accompanied on both sides by a rather unmetamorphosed foldbelt. It is speculated that the crystalline ridge represents some kind of island arc system underlain by a segment of continental crust. On both sides this island arc system was involved in subduction of oceanic crust, first of the Mideuropean Sea in the North and then of the Paleotethys in the South. When the continental areas to the north and south of the oceanic areas (North America/Northern Europe and Africa) finally got involved in the subduction processes, continent/continent collision took place on both sides of the island arc system. The tw…
Generation of Earth's early continents from a relatively cool Archean mantle
2019
This research has been supported by DFG grant, SPP 1833 Building a Habitable Earth and MAGMA Consolidator Grant (ERC project #71143). Several lines of evidence suggest that the Archean (4.0 2.5 Ga) mantle was hotter than today's potential temperature (TP) of 1350 ° C. However, the magnitude of such difference is poorly constrained, with TP estimation spanning from 1500 ° C to 1600 ° C during the Meso‐Archean (3.2‐2.8 Ga). Such differences have major implications for the interpreted mechanisms of continental crust generation on the early Earth, as their efficacy is highly sensitive to the TP. Here, we integrate petrological modeling with thermomechanical simulations to understand the dynami…
The relationship between eruptive activity, flank collapse, and sea level at volcanic islands: A long-term (>1 Ma) record offshore Montserrat, Les…
2016
Hole U1395B, drilled southeast of Montserrat during Integrated Ocean Drilling Program Expedition 340, provides a long (>1 Ma) and detailed record of eruptive and mass-wasting events (>130 discrete events). This record can be used to explore the temporal evolution in volcanic activity and landslides at an arc volcano. Analysis of tephra fall and volcaniclastic turbidite deposits in the drill cores reveals three heightened periods of volcanic activity on the island of Montserrat (∼930 to ∼900 ka, ∼810 to ∼760 ka, and ∼190 to ∼120 ka) that coincide with periods of increased volcano instability and mass-wasting. The youngest of these periods marks the peak in activity at the Soufriere Hills vol…
The radiogenic isotope composition of the high-latitude North Atlantic mantle
1997
New Sr, Nd, and Pb isotope data on North Atlantic high-latitude (about 69°30'N to 76°30'N) intraplate and ridge volcanic rocks, together with published data, are used to evaluate the mantle sources contributing to Iceland and the surrounding ridges. Considerable overlap between Icelandic lavas and depth-filtered North Atlantic mid-oceanic-ridge basalts (MORBs) in all isotope plots confirm that a MORB asthenosphere-plume mixing model can explain the ranges of isotope compositions found on Iceland. Regional isotope patterns north of lat 53°N show two distinct mantle domains. Lavas forming a low-radiogenic-Pb, high-radiogenic-Sr array occur north of central Iceland, whereas volcanic rocks form…
Dilatant plasticity applied to Alpine collision: ductile void growth in the intraplate area beneath the Eifel volcanic field
1998
The Eifel is located in the middle of the European plate far away from any active plate boundary, yet it appears to be a maximum of intraplate tectonic activity. A map of intraplate seismic energy flow shows that the Eifel is linked to the Alpine collisional belt via a narrow seismoactive shear zone. Two parallel Quaternary volcanic zones (the East Eifel Volcanic Zone EEVZ and the West Eifel Volcanic Zone WEVZ) line up with the seismogenic shear zone. Xenoliths ejected from these volcanic lineaments indicate upper mantle shearing by dynamic recrystallization textures and metasomatized chemistry. Important CO2-dominated mantle degassing observed in mineral springs, lakes or dry degassing sug…
Middle Jurassic–Early Cretaceous tectono-sedimentary evolution of the southwestern Iberian Basin (central Spain): Major palaeogeographical changes in…
2019
Abstract The Middle Jurassic-Early Cretaceous tectono-sedimentary evolution of the southwestern part of the intraplate Iberian Basin (Spain) was mostly controlled by the Alto Tajo-Montes Universales (ATMU) and Landete-Teruel (LT) faults. During the Middle Jurassic, the ATMU fault separated a western area dominated by shallow marine carbonates, and an eastern area with open marine facies. During the Bathonian-Callovian, the area located to the west of the ATMU fault and north of the LT fault (Cuenca domain) was progressively exposed, and remained uplifted until the late Barremian. A widespread unconformity with a variable gap around the Callovian to mid-Oxfordian has been related to the onse…
PAN-AFRICAN MOBILE BELTS AS EVIDENCE FOR A TRANSITIONAL TECTONIC REGIME FROM INTRAPLATE OROGENY TO PLATE MARGIN OROGENY
1979
Pan-African belts of the African mainland and the Arabian-Nubian Shield exhibit evolutionary features which are either compatible with intracontinental ensialic development or with plate margin and Wilson cycle tectonics. Some of these belts are discussed and, considered together, they appear to reflect variations in crustal mobility during a transitional tectonic regime from intraplate to plate margin orogeny which lasted some 50. Ma from ca. 1000 Ma to ca. 500 Ma ago.