All ICDP Publications with Abstracts
From parent-sysfolder "Publications" + 2 folder-levels deep
619.
Phytoplankton response to climate changes in Lake Baikal during the Holocene and Kazantsevo Interglacials assessed from sedimentary pigments
Journal of Paleolimnology,
37
(2)
177 – 203
2007
ISSN: 09212728Keywords:▾
Buryatia; Eurasia; Lake Baikal; Russian Federation; Selenga Delta; Bacillariophyta; Chlorophyceae; abundance; chlorophyll; climate change; Holocene; interglacial; lacustrine deposit; organic carbon; paleoecology; phytoplankton; pigment; pristine environment
Abstract: ▾ Lake Baikal, an ancient pristine lake in Siberia, has accumulated sediment deposits that span 25 million years. These deposits have the potential to provide a long-term record of climate changes and their interaction with the ecology of the lake. In order to investigate whether sedimentary phytoplankton pigments could be used to reconstruct past changes in total phytoplankton abundance and productivity, we compared the spatial variability in sedimentary pigment distributions in Holocene cores from three separate regions of the lake; Vidrino in the south, Posolski on Selenga Delta and Continent Ridge in the north. Furthermore, we present the first continuous sedimentary pigment and organic carbon sequence of the Kazantsevo interglacial (roughly a time equivalent to the European Eemian, and Marine Isotopic Stage MIS5e) at a resolution of approximately 150 years. Results of the spatial study showed marked differences in the sediment pigment deposition. Lowest chlorophyll a plus its degradation products versus organic carbon ratios (Chlas/TOC) indicating lowest production, but highest variability with time (indicating strongest climatic oscillations) were found at Continent Ridge. The study of sedimentary pigments deposited during the last two interglacial periods at Continent Ridge showed Chlas/TOC ratios 50-1000 times higher during the Kazantsevo Interglacial compared to the glacial periods, whereas the TOC content was only five times higher, thus indicating the significance of the Chlas/TOC ratio for the reconstruction of the phytoplankton abundance and productivity. Strong oscillations occurred during the Kazantsevo Interglacial within centennial time scales. Chlorophyllb plus its degradation products provided additional information on the past development of Chlorophyceae. Highest Chlas/TOC ratios were found during the early Holocene at approximately 9 kyr BP. Indications of short phytoplankton production maxima were also found during the late Atlantic (6 kyr BP) and at the Subboreal/Subatlantic transition (3 kyr BP). From this we conclude that sedimentary chlorophyll a is a reliable indicator of phytoplanktonic response to climate changes and may serve for validation of future climate scenarios in continental regions. © 2006 Springer Science+Business Media B.V.
618.
The Role of Fault Zone Drilling
Volume 4
Publisher
Elsevier
2007
617.
10.06 - Exogenic Dynamics, Cratering and Surface Ages
Volume 1-10
2007
616.
[English]
Broadside interferometric and reverse-time imaging of the San Andreas Fault
Page 2175-2179
Publisher
Society of Exploration Geophysicists
2007
Center for Wave Phenomena, Colorado School of Mines, Golden, CO 80401, United States; Earth and Ocean Sciences Division, Duke University, Durham, NC 27708, United States; Paulsson Geophysical Services, Inc., Brea, CA 92821, United StatesISBN:
9781604238976
615.
[English]
Characterisation and engineering properties of methane hydrate soils
Volume 3-4
,
Page 2591-2642
2007
University of Cambridge, Cambridge, United Kingdom; Technion, Israel Institute of Technology, Haifa, IsraelISBN:
9780415402675
614.
[English]
Integrated petrophysical and borehole seismic studies of Lake Bosumtwi impact crater, Ghana
Volume 26
,
Page 447 – 451
Publisher
Society of Exploration Geophysicists
2007
Keywords:▾
Lakes; Pore size; Rocks; Seismic waves; Seismology; Shear waves; Bimodal distribution; Different sizes; Geophysical logging; Impact structures; Interstitial materials; Laboratory measurements; Linear relationships; Seismic measurements; Seismic prospecting
ISBN:
978-160423897-6
613.
[English]
Migration-based location of the SAFOD target-earthquakes
Volume 2
,
Page 797-801
Publisher
Society of Petroleum Engineers
2007
Berlin Free UniversityISBN:
9781605601557
612.
[English]
Monitoring microearthquakes with the San Andreas fault observatory at depth
Volume 2
,
Page 747-751
Publisher
Society of Petroleum Engineers
2007
NORSAR; USGSISBN:
9781605601557
611.
[English]
Sulfur geochemistry in the HSDP2 drilling, Hawaii: Effects of lava degassing and sea-water interaction
Volume 1
,
Page 61 – 64
2007
ISBN:
978-041545135-2
610.
Continental drilling and the study of impact craters and processes - An ICDP perspective
2007
609.
μ-Synchrotron radiation excited X-ray fluorescence microprobe trace element studies on spherules of the Cretaceous/Tertiary boundary transitions of NE-Mexico and Haiti samples
Spectrochimica Acta - Part B Atomic Spectroscopy,
62
(8)
824-835
2007
Abstract: ▾ Synchrotron radiation, collimated to a μm scale was used for the determination of trace elements in micro-tektites and spherule material for the first time. The experimental set-up of the SXRF microprobe at beamline L at HASYLAB at DESY offers a suitable method for performing non-destructive in situ multi-element analysis focusing on spatial trace element distributions and mineral phases of the melted ejecta material from the Cretaceous/Tertiary boundary. The spatial distribution of trace elements was determined in melt inclusions as well as in phase transitions in selected parts of chlorite-smectite spherules and tektite glass material by using a beam with a diameter of 15 μm collimated with a glass capillary for line- and area scans as well as for single point measurements for elements with Z between 19 and 92. The analyzed spherules show alteration features but also zonation and carbonate inclusions, originating from the Chicxulub impact event. These initial results demonstrate the potential of μ-SXRF analysis for the discrimination of alteration and primary signals of the spherules and re-construction of their genetic evolution. It could be shown that the spherules represent a complex mixture of different materials from the subsurface at the Chicxulub impact site. © 2007 Elsevier B.V. All rights reserved.
608.
Talc-bearing serpentinite and the creeping section of the San Andreas fault
Nature,
448
(7155)
795-797
2007
ISSN: 00280836
Publisher: Nature Publishing Group
Keywords:▾
mineral; serpentine; talc, creep; fault slip; fault zone; hydrothermal fluid; San Andreas Fault; serpentinite; shear strength; sliding; talc; ultramafic rock, article; chemical reaction; friction; gravity; priority journal; rock; temperature, California; Cholame Valley; North America; San Juan Bautista; San Luis Obispo County; United States
Abstract: ▾ The section of the San Andreas fault located between Cholame Valley and San Juan Bautista in central California creeps at a rate as high as 28 mm yr -1 (ref. 1), and it is also the segment that yields the best evidence for being a weak fault embedded in a strong crust. Serpentinized ultramafic rocks have been associated with creeping faults in central and northern California, and serpentinite is commonly invoked as the cause of the creep and the low strength of this section of the San Andreas fault. However, the frictional strengths of serpentine minerals are too high to satisfy the limitations on fault strength, and these minerals also have the potential for unstable slip under some conditions. Here we report the discovery of talc in cuttings of serpentinite collected from the probable active trace of the San Andreas fault that was intersected during drilling of the San Andreas Fault Observatory at Depth (SAFOD) main hole in 2005. We infer that the talc is forming as a result of the reaction of serpentine minerals with silica-saturated hydrothermal fluids that migrate up the fault zone, and the talc commonly occurs in sheared serpentinite. This discovery is significant, as the frictional strength of talc at elevated temperatures is sufficiently low to meet the constraints on the shear strength of the fault, and its inherently stable sliding behaviour is consistent with fault creep. Talc may therefore provide the connection between serpentinite and creep in the San Andreas fault, if shear at depth can become localized along a talc-rich principal-slip surface within serpentinite entrained in the fault zone. ©2007 Nature Publishing Group.
607.
The Lake Bosumtwi impact structure in Ghana: A brief environmental assessment and discussion of ecotourism potential
Meteoritics and Planetary Science,
42
(4-5)
561 – 567
2007
ISSN: 10869379
Publisher: University of Arkansas
Abstract: ▾ Lake Bosumtwi is a natural inland freshwater lake that originated from a meteorite impact. The lake is becoming a popular tourist attraction in Ghana and has the potential to be developed as an ecotourism site in the future. However, there have been some unregulated human activities and unplanned infrastructure development, and there are increased levels of pollutants in the lake water. In order to make ecotourism at Lake Bosumtwi successful in the long term, the Lake Bosumtwi Development Committee has been formed to ensure that local people are empowered to mobilize their own capacities. It has been realized that an important criterion required to develop ecotourism in a socially responsible, economically efficient, and environmentally viable way is to foster a constructive dialogue between the local people and tourists about the needs of the indigenous people. © The Meteoritical Society, 2007. Printed in USA.
606.
The Campi Flegrei deep drilling project
Scientific Drilling
(4)
48 – 50
2007
ISSN: 18163459605.
The Chicxulub impact event and its environmental consequences at the Cretaceous-Tertiary boundary
Palaeogeography, Palaeoclimatology, Palaeoecology,
255
(1-2)
4-21
2007
Abstract: ▾ An impact-mass extinction hypothesis for the Cretaceous-Tertiary (K/T) boundary transition has been confirmed with multiple lines of evidence, beginning with the discovery of impact-derived Ir in K/T boundary sediments and culminating in the discovery of the Chicxulub impact crater. Likewise, a link between the Chicxulub impact crater and K/T boundary sediments has been confirmed with multiple lines of evidence, including stratigraphic, petrological, geochemical, and isotopic data. The environmental effects of the Chicxulub impact event were global in their extent, largely because of the interaction of ejected impact debris with the atmosphere. The environmental consequences of the Chicxulub impact event and their association with the K/T boundary mass extinction event indicate that impact cratering processes can affect both the geologic and biologic evolution of our planet. © 2007 Elsevier B.V. All rights reserved.
604.
603.
The Corinth Rift laboratory or an in situ investigation on interactions between fluids and active faults
Scientific Drilling
(1 SUPPL. 1)
35 – 38
2007
ISSN: 18163459602.
The Cretaceous Songliao Basin: Volcanogenic Succession, Sedimentary Sequence and Tectonic Evolution, NE China
Acta Geologica Sinica - English Edition,
81
(6)
1002-1011
2007
Keywords:▾
Cretaceous superposed Songliao basin, volcanic rocks, sedimentary sequence, tectonic evolution, Mongolia-Okhotsk collisional belt, Pacific and Eurasian plates, retroarc strike-slip tectonic-inverse basins
Abstract: ▾ Abstract: The Songliao basin (SB) is a superposed basin with two different kinds of basin fills. The lower one is characterized by a fault-bounded volcanogenic succession comprising of intercalated volcanic, pyroclastic and epiclastic rocks. The volcanic rocks, dating from 110 Ma to 130 Ma, are of geochemically active continental margin type. Fast northward migration of the SB block occurred during the major episodes of the volcanism inferred from their paleomagnetic information. The upper one of the basin fill is dominated by non-marine sag-style sedimentary sequence of siliciclastics and minor carbonates. The basin center shifted westwards from the early to late Cretaceous revealed by the GGT seismic velocity structure suggesting dynamic change in the basin evolution. Thus, a superposed basin model is proposed. Evolution of the SB involves three periods including (1) Alptian and pre-Aptian: a retroarc basin and range system of Andes type related to Mongolia-Okhotsk collisional belt (MOCB); (2) Albian to Companian: a sag-like strike-slip basin under transtension related to oblique subduction of the Pacific plate along the eastern margin of the Eurasian plate; (3) since Maastrichtian: a tectonic inverse basin under compression related to normal subduction of the Pacific plate under the Eurasian plate, characterized by overthrust, westward migration of the depocenter and eastward uplifting of the basin margin.
601.
The ICDP Lake Bosumtwi impact crater scientific drilling project (Ghana): Core LB-08A litho-log, related ejecta, and shock recovery experiments
Meteoritics and Planetary Science,
42
(4-5)
635 – 654
2007
ISSN: 10869379
Publisher: University of Arkansas
Abstract: ▾ The 1.07 Myr old Lake Bosumtwi impact crater in Ghana was drilled within the framework of the International Continental Scientific Drilling Project (ICDP). Hole LB-08A, drilled into the outer flank of the central uplift and with a total depth of 451 m, yielded 215.71 m of impact-related rocks. This paper summarizes observations of the lithological logging on core LB-08A. Between a depth of 235.6 and ∼260 m, the section consists of a melt-bearing allochthonous, polymict, and mostly clast-supported impact breccia. Down to ∼418 m, the section comprises a rather uniform unit of meta-graywacke alternating with phyllite to slate (lower greenschist facies); few (par-) autochthonous impact breccia bodies and rare impact dike breccias are present. The lowermost part of the section contains several centimeter- to decimeter-thick melt-bearing breccia dikes in country rocks identical to those occurring above. Omnipresent fracturing was mapped in a qualitative manner. Most prominent shock effects in the uplifted target rocks comprise planar fractures and deformation elements in quartz and polysynthetic twinning in carbonate minerals; the maximum shock pressure as evidenced by quartz is below 26 GPa. The allochthonous breccias occasionally contain a few vol% of melt particles. Suevites occur outside the crater rim, carrying diaplectic crystals, coesite, and ballen quartz as well as true melt glasses and a variety of lithic clasts, among those spectacular staurolite-rich mica-schists. The recorded shock level in the uplifted target rocks is lower than expected and modeled. Shock recovery experiments with analogue carbonaceous graywackes at 34 and 39.5 GPa yielded nearly complete transformation of quartz into diaplectic glass. We therefore exclude a specific shock behavior of the soft, fluid-rich target material (carbonaceous graywackes, shales, slates) in core LB-08A as the prime or only reason for the melt deficit and the generally low shock levels recorded inside the Lake Bosumtwi impact crater. © The Meteoritical Society, 2007. Printed in USA.
600.
The Lake Bosumtwi meteorite impact structure, Ghana - A magnetic image from a third observational level
Meteoritics and Planetary Science,
42
(4-5)
793 – 800
2007
ISSN: 10869379
Publisher: University of Arkansas
Abstract: ▾ The Bosumtwi impact structure in Ghana is the youngest and best-preserved medium-sized impact structure on Earth, and because of the vast amount of prior geophysical and geological data gathered in the area, it constitutes a great natural laboratory to try to develop new geophysical interpretation and modeling techniques. During the 2004 International Continental Scientific Drilling Program (ICDP) drilling campaign at Lake Bosumtwi, we made magnetic field observations at 162 stations around the lake. This study differs from all previous magnetic surveys at Bosumtwi, which only measured the scalar portion of the Earth's magnetic field, in that we measured the full magnetic vector at each station. Acquisition of the full magnetic vector was made possible by innovative use of a borehole deviation probe, which uses a magnetic sensor for absolute orientation reference. Estimates of the magnetic vector orientation and magnitude at each observation station were derived from a series of measurements collected at 50 cm spacing over a depth range of 25 m. In this study, we report a comparison between the scalar total field intensity derived from this new survey approach with the other two previously acquired marine and airborne magnetic data sets. The scalar total magnetic intensity (TMI) computed from the vector data set compares in close agreement with the other two data sets. Some discrepancies between the data sets can be explained by differences in the distances between the sensor and the magnetic sources for the various surveys. The highlight of this study is that we demonstrate that is possible to acquire at least partial vector data with readily available instrumentation. © The Meteoritical Society, 2007. Printed in USA.
599.
Zoned Zircon from Eclogite Lenses in Marbles from the Dabie-Sulu UHP Terrane, China: A Clear Record of Ultra-deep Subduction and Fast Exhumation
Acta Geologica Sinica - English Edition,
81
(2)
204-225
2007
Keywords:▾
zoned zircon, SHRIMP U-Pb dating, ultra-deep subduction, fast exhumation, eclogite, lenses in marble, Dabie-Sulu UHP belt
Abstract: ▾ Abstract: Eclogite lenses in marbles from the Dabie-Sulu ultrahigh-pressure (UHP) terrane are deeply subducted meta-sedimentary rocks. Zircons in these rocks have been used to constrain the ages of prograde and UHP metamorphism during subduction, and later retrograde metamorphism during exhumation. Inherited (detrital) and metamorphic zircons were distinguished on the basis of transmitted light microscopy, cathodoluminescence (CL) imaging, trace element contents and mineral inclusions. The distribution of mineral inclusions combined with CL imaging of the metamorphic zircon make it possible to relate zircon zones (domains) to different metamorphic stages. Domain 1 consists of rounded, oblong and spindly cores with dark-luminescent images, and contains quartz eclogite facies mineral inclusion assemblages, indicating formation under high-pressure (HP) metamorphic conditions of T = 571–668°C and P = 1.7-2.02 GPa. Domain 2 always surrounds domain 1 or occurs as rounded and spindly cores with white-luminescent images. It contains coesite eclogite facies mineral inclusion assemblages, indicating formation under UHP metamorphic conditions of T = 782–849°C and P > 5.5 GPa. Domain 3, with gray-luminescent images, always surrounds domain 2 and occurs as the outermost zircon rim. It is characterized by low-pressure mineral inclusion assemblages, which are related to regional amphibolite facies retrograde metamorphism of T = 600–710°C and P = 0.7-1.2 GPa. The three metamorphic zircon domains have distinct ages; sample H1 from the Dabie terrane yielded SHRIMP ages of 245 ± 4 Ma for domain 1, 235 ± 3 Ma for domain 2 and 215 ± 6 Ma for domain 3, whereas sample H2 from the Sulu terrane yielded similar ages of 244 ± 4 Ma, 233 ± 4 Ma and 214 ± 5 Ma for Domains 1, 2 and 3, respectively. The mean ages of these zones suggest that subduction to UHP depths took place over 10–11 Ma and exhumation of the rocks occurred over a period of 19–20 Ma. Thus, subduction from ∼ 55 km to > 160 km deep mantle depth took place at rates of approximately 9.5–10.5 km/Ma and exhumation from depths >160 km to the base of the crust at −30 km occurred at approximately 6.5 km/Ma. We propose a model for these rocks involving deep subduction of continental margin Iithosphere followed by ultrafast exhumation driven by buoyancy forces after break-off of the UHP slab deep within the mantle.
598.
The Lake Bosumtwi meteorite impact structure, Ghana - Where is the magnetic source?
Meteoritics and Planetary Science,
42
(4-5)
867 – 882
2007
ISSN: 10869379
Publisher: University of Arkansas
Abstract: ▾ The Bosumtwi impact structure (Ghana) is a young and well-preserved structure where a vast amount of information is available to constrain any geophysical model. Previous analysis of the airborne magnetic data and results of numerical simulation of impact predicted a strongly magnetic impact-melt body underneath the lake. Recent drilling through the structure did not penetrate such an expected impact-melt rock magnetic source. A new 3-D magnetic model for the structure was constructed based on a newly acquired higher-resolution marine magnetic data set, with consideration of the observed gravity data on the lake, previous seismic models, and the magnetic properties and lithology identified in the two International Continental Scientific Drilling Program (ICDP) deep boreholes. The new model contains highly magnetic bodies located in the northeast sector of the structure, not centered onto the drilling sites. As in previous models, higher magnetization than that measured in outcropping impactites had to be assigned to the unexposed source bodies. Integration of the new model with the borehole petrophysics and published geology indicates that these bodies likely correspond to an extension to the south of the Kumasi batholith, which outcrops to the northeast of the structure. The possibility that these source bodies are related to the seismically identified central uplift or to an unmapped impact-melt sheet predicted by previous models of the structure is not supported. Detailed magnetic scanning of the Kumasi batholith to the north, and the Bansu intrusion to the south, would provide a test for this interpretation. © The Meteoritical Society, 2007. Printed in USA.
597.
The pollen record from El'gygytgyn Lake: Implications for vegetation and climate histories of northern Chukotka since the late middle Pleistocene
Journal of Paleolimnology,
37
(1)
135-153
2007
ISSN: 09212728Keywords:▾
paleoclimate; paleoecology; palynology; Pleistocene; pollen; vegetation history, Chukchi; Eurasia; Lake El'gygytgyn; Russian Federation
Abstract: ▾ Three types of pollen assemblages (shrub-dominated, mixed herb- and shrub-dominated, and herb-dominated) characterize the ∼300,000 year palynological record from El'gygytgyn Lake. Despite major changes in global climatic forcings, all pollen spectra, with a few isolated exceptions, have strong to possible analogs in the modern plant communities of Northeast Siberia and Alaska. Paleoclimatic reconstructions based on squared chord-distance analog analyses indicate two periods (∼8600-10,700 14C year B.P. and OIS 5e) when summers were perhaps ∼2 to 4°C warmer than modern. January temperatures were also warmer than present, and both July and January were wetter than today. Palynological data remain inconclusive as to the establishment of forests near El'gygytgyn Lake at these times. The wettest Julys occurred during OIS 5 d. July temperatures were near modern, and Januarys were colder and drier than now. January temperatures, even into the Middle Pleistocene, generally show little variability, suggesting that the suppression of arboreal taxa during glaciations was likely caused by cool summers with low effective moisture and not by frigid winters. Because age schemes that correlate magnetic susceptibility to variations in summer insolation or ∂18O have cool plant taxa persisting in warm times (and vice versa), we propose an alternative age model based on the palynological data. © 2006 Springer Science+Business Media B.V.
596.
Ultrahigh-pressure mineral assemblages in zircons from the surface to 5158 m depth in cores of the main drill hole, Chinese Continental Scientific Drilling Project, Southwestern Sulu Belt, China
International Geology Review,
49
(5)
454 – 478
2007
ISSN: 00206814Keywords:▾
Asia; China; Eurasia; Far East; Sulu Belt; amphibolite facies; crustal structure; eclogite; exhumation; fluid inclusion; Ocean Drilling Program; orthogneiss; retrograde metamorphism; subduction; ultrahigh pressure metamorphism; ultramafic rock; zircon
Abstract: ▾ The 5158 m deep main hole of the Chinese Continental Scientific Drilling Project (CCSD-MH) at Maobei, southwestern Sulu Belt, penetrated five major lithologic units: eclogite, amphibolite ± retrograde eclogite, ultramafic rock, paragneiss, and orthogneiss. All analyzed samples are overprinted to various extents by amphibolite-facies retrograde metamorphism. Ultrahigh-pressure (UHP) index minerals are preserved as inclusions in zircons separated from 137 core samples. These index assemblages include: Coe + Phe + Grt from Grt-Ep-Bt paragneiss; Coe + Jd + Grt + Ap, Coe + Jd + Phe + Ap and Coe + Grt + Jd + Phe from Grt-Ep-Hbl paragneiss; Coe + Phe, Coe + Ky + Ap, and Coe + Ky + Ttn from orthogneiss; and Coe + Grt + Omp, Coe + Grt + Phe, Coe + Omp + Rt, and Coe + Grt + Omp + Phe from Bt-Ep amphibolite and other retrograde eclogites. The common occurrences of these UHP assemblages throughout the section indicate that the drill hole did not penetrate through the UHP tectonic slice. All of the UHP mineral assemblages, whether from retrograde ecologites or from the surrounding gneisses, record similar metamorphic conditions of 773-843°C and 3.2-4.0 GPa. Zircons separated from surface samples and cores from other shallow holes in the area also contain similar coesite-bearing UHP mineral inclusions. This widespread occurrence of UHP assemblages in the southwestern Sulu area suggests that voluminous continental materials were subducted and metamorphosed at mantle depths > 100 km, and then were rapidly exhumed to crustal levels. Copyright © 2007 by V. H. Winston & Son, Inc. All rights reserved.
595.
Upper mantle beneath the Eger Rift (Central Europe): Plume or asthenosphere upwelling?
Geophysical Journal International,
169
(2)
675 – 682
2007
ISSN: 1365246XKeywords:▾
Bohemian Massif; Central Europe; Eurasia; Europe; asthenosphere; lithosphere; P-wave; rift zone; seismic anisotropy; seismic tomography; teleseismic wave; travel time; upper mantle
Abstract: ▾ We present the first results of a high-resolution teleseismic traveltime tomography and seismic anisotropy study of the lithosphere-asthenosphere system beneath the western Bohemian Massif. The initial high-resolution tomography down to a depth of 250 km did not image any columnar low-velocity anomaly which could be interpreted as a mantle plume anticipated beneath the Eger Rift, similar to recent findings of small plumes beneath the French Massif Central and the Eifel in Germany. Alternatively, we interpret the broad low-velocity anomaly beneath the Eger Rift by an upwelling of the lithosphere-asthenosphere transition. We also map lateral variations of seismic anisotropy of the mantle lithosphere from spatial variations of P-wave delay times and the shear wave splitting. Three major domains characterised by different orientations of seismic anisotropy correspond to the major tectonic units - Saxothuringian, Moldanubian and the Teplá-Barrandian - and their fabrics fit to those found in our previous studies of mantle anisotropy on large European scales. © 2007 The Authors Journal compilation © 2007 RAS.