Investigation of the 600-km discontinuity under France through travel-time and amplitude anomalies     

Pierre Mechler  Raouf Mseddi  Emile Okal  Jean-Louis Plantet  Yves Rocard 《Physics of the Earth and Planetary Interiors》1974,8(3):269-276

In this paper, we give a model of the 600-km discontinuity under France, which explains large travel-time and amplitude anomalies on teleseisms as recorded in the French network. It features a large descent from the Ardennes to the Pyrénées, of which tectonic implications are discussed.  相似文献   

Petrography and paleo-environment of continental carbonate deposits with particular reference to the upper cretaceous and lower eocene of languedoc (Southern France)     

Pierre Freytet 《Sedimentary Geology》1973,10(1):25-60

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Narrative warm/cold variations in continental western Europe, AD 708 -1426     

Zhongwei Yan  Alexandre Pierre  Demarée Gaston 《中国科学D辑(英文版)》1997,40(5):509-517

An extended narrative dataset of the Medieval time AD 708-1426 in continental western Europe was set up. Some 30-year-moving mean seasonal temperature deviation series were reconstructed. A- warming trend occurred around AD 1200. During the warm stage, seasonal cycle might be weak due to frequent cool summers. Significant warm summer conditions did not occur until the late 14th century, when the annual temperature level began decreasing. The mean warm season temperature level during the late 14th to the early 15th century might be about 0.3°C higher than the present. It was suggested to cautiously comment on historical climates for different seasons.  相似文献   

Automated trend reinforcement of aeromagnetic data     

Pierre Keating 《Geophysical Prospecting》1997,45(3):521-534

Aeromagnetic maps poorly represent lineaments that are at acute angles to the flight-line direction. Commonly used gridding algorithms cannot cope with local trends, magnetic anomalies at an angle with the main trend of the map, and tend to generate closed contours around the flight lines. By introducing some a priori information, it is possible to add extra data between the flight lines, i.e. trend lines, to reinforce local trends. The proposed automated technique is based on a nearest neighbour search of the maxima and minima in the aeromagnetic map. The resulting map is more realistic and derived maps, such as vertical gradients and analytical signal maps, are greatly improved. Moreover, this automated procedure is user independent and easy to implement. The technique is demonstrated on aeromagnetic data from the Kirkland Lake region, in north-eastern Ontario, Canada.  相似文献   

Compartmentalization of physical and chemical properties in hard-rock aquifers deduced from chemical and groundwater age analyses     

Virginie Ayraud  Luc Aquilina  Thierry Labasque  Hélène Pauwels  Jérôme Molenat  Anne-Catherine Pierson-Wickmann  Véronique Durand  Olivier Bour  Corinne Tarits  Pierre Le Corre  Elise Fourre  Philippe Merot  Philippe Davy 《Applied Geochemistry》2008

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A high-energy solar flare burst complex and the physical properties of its source region     

Cornelis De Jager  Jan Kuijpers  Emilia Correia  Pierre Kaufmann 《Solar physics》1987,110(2):317-326

We discuss a solar flare microwave burst complex, which included a major structure consisting of some 13 spikes of 60 ms FWHM each, observed 21 May, 1984 at 90 GHz (3 mm). It was associated with a simultaneous very hard X-ray burst complex. We suggest that the individual spikes of both bursts were caused by the same electron population: the X-bursts by their bremsstrahlung, and the microwave bursts by their gyrosynchrotron emission. This latter conclusion is based on the evidence that the radio turnover frequency was 150 GHz. It follows that the emission sources were characterized by an electron density of about 10¹¹ cm^–3, a temperature of 5 × 10⁸ K and a magnetic field of about 1400–2000 G. They had a size of about 350 km; if the energy release is caused by reconnection the sources of primary instability could have been smaller and in the form of thin sheets with reconnection speed at a fraction of the Alfvén velocity and burst-like energy injections of 10²⁷ erg during about 50 ms each. The energized plasma knots lost their injection energy by saturated convective flux (collisionless conduction) in about 30 ms.  相似文献   

Slope‐to‐basin stratigraphic evolution of the northwestern Great Bahama Bank (Bahamas) during the Neogene to Quaternary: interactions between downslope and bottom currents deposits          下载免费PDF全文

Mélanie Principaud  Jean‐Pierre Ponte  Thierry Mulder  Hervé Gillet  Cécile Robin  Jean Borgomano 《Basin Research》2017,29(6):699-724

Multichannel high‐resolution seismic data along the northwestern margin of the Great Bahama Bank (GBB), Bahamas, detail the internal geometry and depositional history of a Neogene‐Quaternary carbonate slope‐to‐basin area. The stratigraphic architecture through this period evolves from (i) a mud‐dominated slope apron during the Miocene, (ii) a debris‐dominated base‐of‐slope apron during the Late Pliocene and then (iii) return to a slope apron with very short prograding clinoformal aprons during the Pleistocene. This geometric evolution was broadly constrained by the development of the Santaren Drift by bottom current since the Langhian. The drift expands along the northwestern GBB slope, forming a continuous correlative massive feature that shows successive phases of growth and retreat and influenced the downslope sediments distribution. Indeed, Late Pliocene deposits are confined into the moat, forming a strike‐continuous coarse debrites belt along the mid‐slope, preventing their free expansion into the basin. The occurrence of basinal drift that operated since 15 Ma showed a significant upslope growth around 3.6 Ma and is interpreted as resulting from the closure of the Central American Seaway which also coincides with a global oceanographic re‐organization and climate changes in the Northern Hemisphere.  相似文献   

Seismic stratigraphy and paleogeographic evolution of Fairway Basin,Northern Zealandia,Southwest Pacific: from Cretaceous Gondwana breakup to Cenozoic Tonga–Kermadec subduction          下载免费PDF全文

Pierrick Rouillard  Julien Collot  Rupert Sutherland  Francois Bache  Martin Patriat  Samuel Etienne  Pierre Maurizot 《Basin Research》2017,29(Z1):189-212

We present the first comprehensive seismic‐stratigraphic analysis of Fairway Basin, which is situated on the rifted continent of Zealandia in the Tasman Sea, southwest Pacific, between Australia and New Caledonia. The basin is 700 km long, 150 km wide, and has water depths of 500–3000 m. We describe depositional architecture and paleogeographic evolution of this basin. Basin formation was concurrent with two tectonic events: (i) Cretaceous rifting during eastern Gondwana breakup and (ii) initiation and Cenozoic evolution of Tonga–Kermadec subduction system to the east of the basin. To interpret the basin history we compiled and interpreted 2D seismic‐reflection profiles and make correlations with DSDP boreholes and the geology of New Caledonia. Five seismic‐stratigraphic units were defined. The deepest and oldest unit, FW3, folded and faulted can be correlated with volcaniclastic sediments and magmatic rocks in New Caledonia that are associated with Mesozoic Gondwana margin subduction. Alternatively, given the basin location 200–300 km west of New Caledonia and inboard of the ancient plate boundary, the unit could have formed as Gondwana intra‐continental basin with no known correlative. The overlying unit FW2b records syn‐rift deposition, probably associated with Cretaceous Gondwana breakup. Subaerial erosion supplied terrigenous sediment into the deltas in the northern part of the basin, as suggested by the truncation surfaces on the basement highs and sigmoid reflector geometries within unit FW2b respectively. Above, unit FW2a records post‐rift sedimentation and passive subsidence as the Tasman Sea opened and the Fairway Basin drifted away from Australia. Subsidence led to the flooding of the basement highs and burial of wave‐cut surfaces. Eocene compressive deformation resulted in minor folding and tilting within the Fairway Basin and was associated with the formation of many diapiric structures. The top of unit FW2 is an extensive unconformity that is associated with erosion and truncation on surrounding ridges. Above this unconformity, unit FW1b is interpreted as a turbidite system sourced from topography created during the Eocene tectonic event, which we interpret as being related to Tonga–Kermadec subduction initiation. Pelagic carbonate sedimentation is now prevalent. Unit FW1a has progressively draped the basin during Oligocene to Pleistocene subsidence. Many small volcanic cones were erupted during this final phase of subsidence, either as a delayed consequence of subduction initiation, or related to Tasmantid and Lord Howe hotspot trails. The northern Fairway Ridge remains close to sea level and its reef system continues to supply carbonate detrital sediments into the basin, most likely during sea‐level lowstands. Fairway Basin contains a nearly continuous record of tectonic and paleoclimatic events in the southwest Pacific since Cretaceous time. Its paleogeographic history is a key piece in the puzzle for understanding patterns of regional biodiversity in the southwest Pacific.  相似文献   

Integration of data and computing infrastructures for earth science: an image mosaicking use-case     

Paolo Mazzetti  Roberto Roncella  Danut Mihon  Victor Bacu  Pierre Lacroix  Yaniss Guigoz  Nicolas Ray  Gregory Giuliani  Dorian Gorgan  Stefano Nativi 《Earth Science Informatics》2016,9(3):325-342

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Passive acoustic recording of Ophidion rochei calling activity in Calvi Bay (France)          下载免费PDF全文

Loïc Kéver  Pierre Lejeune  Loïc N. Michel  Eric Parmentier 《Marine Ecology》2016,37(6):1315-1324

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