scholarly journals Sedimentary dynamics on isolated highs in Lake Baikal: evidence from detailed high-resolution geophysical data and sediment cores

2005 ◽  
Vol 46 (1-4) ◽  
pp. 125-144 ◽  
Author(s):  
F. Charlet ◽  
N. Fagel ◽  
M. De Batist ◽  
F. Hauregard ◽  
B. Minnebo ◽  
...  
Keyword(s):  
High Resolution ◽  
Lake Baikal ◽  
Sediment Cores ◽  
Geophysical Data ◽  
Sedimentary Dynamics

Airborne geophysical surveys in Greenland in 1998

1999 ◽  
pp. 34-38 ◽  
Author(s):  
Thorkild M. Rasmussen ◽  
Leif Thorning
Keyword(s):  
High Resolution ◽  
Geophysical Data ◽  
Digital Data ◽  
Geological Survey ◽  
Magnetic Data ◽  
Magnetic Survey ◽  
Original Series ◽  
Geophysical Surveys ◽  
The Government

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Rasmussen, T. M., & Thorning, L. (1999). Airborne geophysical surveys in Greenland in 1998. Geology of Greenland Survey Bulletin, 183, 34-38. https://doi.org/10.34194/ggub.v183.5202 _______________ Airborne geophysical surveying in Greenland during 1998 consisted of a magnetic project referred to as ‘Aeromag 1998’ and a combined electromagnetic and magnetic project referred to as ‘AEM Greenland 1998’. The Government of Greenland financed both with administration managed by the Geological Survey of Denmark and Greenland (GEUS). With the completion of the two projects, approximately 305 000 line km of regional high-resolution magnetic data and approximately 75 000 line km of detailed multiparameter data (electromagnetic, magnetic and partly radiometric) are now available from government financed projects. Figure 1 shows the location of the surveyed areas with highresolution geophysical data together with the area selected for a magnetic survey in 1999. Completion of the two projects was marked by the release of data on 1 March, 1999. The data are included in the geoscientific databases at the Survey for public use; digital data and maps may be purchased from the Survey.

Aeromagnetic survey in central West Greenland: project Aeromag 2001

2002 ◽  
pp. 67-72 ◽  
Author(s):  
Thorkild M. Rasmussen
Keyword(s):  
High Resolution ◽  
Magnetic Measurements ◽  
Geophysical Data ◽  
High Quality ◽  
Aeromagnetic Survey ◽  
Original Series ◽  
West Greenland ◽  
Airborne Measurements ◽  
Geophysical Surveys ◽  
Airborne Geophysical Data

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article. Rasmussen, T. M. (1). Aeromagnetic survey in central West Greenland: project Aeromag 2001. Geology of Greenland Survey Bulletin, 191, 67-72. https://doi.org/10.34194/ggub.v191.5130 The series of government-funded geophysical surveys in Greenland was continued during the spring and summer of 2001 with a regional aeromagnetic survey north of Uummannaq, project Aeromag 2001 (Fig. 1). The survey added about 70 000 line kilometres of high-quality magnetic measurements to the existing database of modern airborne geophysical data from Greenland. This database includes both regional high-resolution aeromagnetic surveys and detailed surveys with combined electromagnetic and magnetic airborne measurements.

High-resolution radiocarbon dating to reconstruct last century environmental changes in the pacific island of Espiritu Santo

2021 ◽  
Author(s):  
Giorgia Camperio ◽  
Caroline Welte ◽  
S. Nemiah Ladd ◽  
Matthew Prebble ◽  
Nathalie Dubois
Keyword(s):  
High Resolution ◽  
Radiocarbon Dating ◽  
Environmental Changes ◽  
Accumulation Rate ◽  
Sediment Cores ◽  
Volcanic Eruptions ◽  
High Accumulation ◽  
Sedimentary Records ◽  
The Pacific ◽  
Rapid Accumulation

<p>Espiritu Santo is one of the 82 islands of the archipelago of Vanuatu and is the largest, highest, and most biodiverse of the insular country. Climatic changes linked to El Niño and extreme events such as cyclones and volcanic eruptions are a daily challenge in this remote area. These events can be recorded in sedimentary archives. Here we present a multi-proxy investigation of sediment cores retrieved from two small lakes located on the West coast of Espiritu Santo. Although the records span the last millennium, high-resolution radiocarbon dating of macrofossils reveals a rapid accumulation of sediment in the past 100 years. The high accumulation rate coupled with the high-resolution dating of freshwater sediments allows us to compare the <sup>14</sup>C bomb curve with the biogeochemical proxies of the sedimentary records. The results can then be validated against written and oral historical records linked with the societal perception of recent environmental changes in this vulnerable ecosystem.</p><div> <div title="Translate selected text"></div> <div title="Play"></div> <div title="Copy text to Clipboard"></div> </div>

Specifics of the Caledonian Collision in the Ol’khon Region (Lake Baikal, Russia)

2021 ◽  
Vol 62 (4) ◽  
pp. 389-400
Author(s):  
V.A. Makrygina
Keyword(s):  
Subduction Zone ◽  
Oceanic Crust ◽  
Lake Baikal ◽  
Siberian Craton ◽  
Island Arc ◽  
Geophysical Data ◽  
Igneous Rocks ◽  
Fold Belt ◽  
Adjacent Part

Abstract —Analysis of geochemical, geochronological, and new geophysical data on metasedimentary and igneous rocks of the Ol’khon region has made it possible to substantiate: (1) the absence of products of the Caledonian suprasubduction magmatism from the adjacent part of the Siberian craton and (2) the presence of a product of this magmatism in the Anga–Talanchan island arc, namely, the Krestovsky massif with gabbro-diorite to granite phases. This suggests subduction of the Paleoasian oceanic crust under the island arc before the collision. The geophysical data showed a steep sinking of the Siberian craton margin. This sinking and the supposed contrary movement and rotation of the Siberian craton prevented the appearance of a subduction zone beneath the craton during the collision but caused the wide development of fault plates in the fold belt at the late collision stage. The residue of oceanic crust slab was pressed out along the fault planes near the surface and formed a row of gabbro-pyroxenite massifs of the Birkhin Complex in the fold belt, where syncollisional granitic melts (Sharanur Complex) formed at the same time. The interaction of two contrasting melts gave rise to the Tazheran and Budun alkaline syenite massifs and alkaline metasomatites of the Birkhin and Ulanganta gabbroid massifs.

Tsunami hazard from lacustrine mass wasting in Lake Tekapo, New Zealand

2018 ◽  
Vol 477 (1) ◽  
pp. 413-426 ◽  
Author(s):  
Joshu J. Mountjoy ◽  
Xiaoming Wang ◽  
Susi Woelz ◽  
Sean Fitzsimons ◽  
Jamie D. Howarth ◽  
...  
Keyword(s):  
High Resolution ◽  
Sediment Cores ◽  
Lake Basin ◽  
Diverse Range ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Tectonically Active ◽  
Tsunami Risk ◽  
Western Shore ◽  
The Impact

AbstractLacustrine-tsunami risk from landslides can be significant yet for most locations globally the hazard remains unquantified. Lake Tekapo, in the tectonically active mountain belt of New Zealand's South Island, has been chosen to develop surveying and modelling techniques to assess the hazard from landslide tsunamis. Lake Tekapo is ideal for this study due to the high sedimentation rates, steep surrounds and the proximity to active faulting that indicate a high landslide potential. The shoreline tourist settlement and hydropower infrastructure mean the impact of any tsunami could be significant. In 2016 a survey was carried out to collect high-resolution (1 m grid) EM2040 multibeam bathymetry, high-resolution seismic reflection data (Boomer and chirp) and 6 m long sediment cores. These data reveal a diverse range of sedimentary processes in response to high sediment input and numerous landslides with varied styles of emplacement. For example, a one-off landslide initiated 40 m above the shoreline with debris deposits that have runout onto the lake floor to 100 m water depth contrasts with the Cass River delta on the western shore that has failed multiple times during the lake-basin infilling history. Landslide-generated tsunami scenarios are used to determine the relative hazard at different regions of the lake to guide development of a probabilistic tsunami model.

Late Holocene glacier and climate reconstruction from proglacial records in Vatnsdalur, northern Iceland.

2020 ◽  
Author(s):  
Konstantin Nebel ◽  
Timothy Lane ◽  
Kathryn Adamson ◽  
Iestyn Barr ◽  
Willem van der Bilt ◽  
...  
Keyword(s):  
High Resolution ◽  
Environmental Change ◽  
North Atlantic ◽  
Late Holocene ◽  
Sediment Cores ◽  
Arctic Region ◽  
Arctic Climate ◽  
The Arctic ◽  
Air Masses ◽  
Proglacial Lake

<p>The Arctic region is experiencing surface air temperature increase of twice the global average. To better understand Holocene Arctic climate variability, there is the need for continuous, high-resolution palaeoclimate archives. Sediment cores from proglacial lakes can provide such climate archives, and have the potential to record past environmental change in detail.       </p><p>Vatnsdalur, a valley in northern Iceland, hosts small, climatically sensitive cirque glaciers that became independent from the Iceland Ice Sheet after its retreat following the Last Glacial Maximum (c. 15 ka BP). Importantly, this region is located at the confluence of warm water and air masses from the south and cold polar water and air masses from the north, making it highly sensitive to North Atlantic and Arctic climate change. However, at present the region is highly understudied, lacking any high-resolution climate reconstructions.           </p><p>To address this, we combine geomorphological mapping with the first high-resolution analysis of proglacial lake sediments, to thoroughly examine northern Iceland Late Holocene environmental change.</p><p>Field mapping supplemented by high-resolution drone data was used to characterise catchment geomorphology, including seven Holocene moraines. A sediment core (SKD-P1-18) from proglacial lake Skeiðsvatn, Vatnsdalur, was analysed for sedimentological (dry bulk density, loss-on-ignition, grain size), geophysical (magnetic susceptibility) and geochemical (X-ray fluorescence core scan, 2 mm resolution) parameters.             <br>We identify three main sedimentary facies from these analyses, indicating variations in glacial input and catchment environmental conditions. Radiocarbon dating of lake macrofossils, supplemented by tephrochronology, provides a chronological framework. Catchment point samples, also analysed using the above analytical techniques, were used for sediment fingerprinting to disentangle non-glacial from glacial end-members.</p><p>Our results indicate the disappearance and reformation of small, climatically sensitive cirque glaciers in Vatnsdalur during the Holocene. We interpret the data to show an abrupt return to a glaciated catchment. Our results fill a geographical gap of high-resolution proglacial sediment studies in the Arctic-North Atlantic region.</p>

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