During the period from 1974 to 2023 various cruises from BGR acquired seismic lines worldwide. The aim of these marine expeditions were a detailed survey of the geological structure of seabed.
The study of the geodynamic evolution of the Arctic continental margin and opening of the Arctic Ocean represents a primary target of BGR research and is studied within the frame of the CASE programme. In addition to onshore geological investigations, BGR conducts airborne aeromagnetic surveys. The available service contains the results of aeromagnetic surveys from the CASE program as well as cooperation projects (PMAP, NARES & NOGRAM), which were obtained with helicopters or fixed-wing aircraft in the Arctic.
In May/June 2001, as part of the expedition NARES I, an aeromagnetic survey was carried out in the area of the eastern Kane Basin in cooperation with the Canadian GSC, in addition to the survey over the Robeson Channel and parallel to marine geophysical investigations with the Canadian icebreaker Louis S. St. Laurent. Another survey, NARES II, was conducted from Alexandra Fiord in 2003 and covered coastal areas of Ellesmere Island and the western Kane Basin. The aim of the research was to detect and localize the Wegener Fault, a transform fault between Ellesmere Island and NW Greenland, which is closely linked to the opening of the North Atlantic and the Arctic Ocean. The helicopter-borne magnetic surveys NARES I + II (Kane Basin) were carried out with a flight line spacing of 2 km, and control profiles were flown every 10 km. During the two expeditions, 11806 km of line data were collected (3573 km in 2001, and 8333 km in 2003), covering an area of approximately 20000 km². The aeromagnetic data were recorded by a magnetometer, which was towed approx. 25 m beneath the helicopter.
During the German-Canadian Nares Strait Expedition in 2001, an aeromagnetic survey was carried out across the northern part of the Nares Strait including the Hall Basin, Judge Daly Promontory and in Robeson Channel in cooperation with the Canadian GSC. The aim of the research was to detect and localize the Wegener Fault, a transform fault between Ellesmere Island and NW Greenland, which is closely linked to the opening of the North Atlantic and the Arctic Ocean. The helicopter-borne magnetic survey NARES I (Robeson Channel) was carried out with a flight line spacing of 2 km, and control profiles were flown every 10 km. During the expedition, 5470 km of line data were collected. The aeromagnetic data were recorded by a magnetometer, which was towed approx. 25 m beneath the helicopter and recorded at a constant altitude of 305 m (1000 ft) above ground.
The study of the geodynamic evolution of the Arctic continental margin and opening of the Arctic Ocean represents a primary target of BGR research and is studied within the frame of the CASE programme. In addition to onshore geological investigations, BGR conducts airborne aeromagnetic surveys. The available series contains the results of aeromagnetic surveys from the CASE program as well as cooperation projects (PMAP, NARES & NOGRAM), which were obtained with helicopters or fixed-wing aircraft in the Arctic.
The web service of the dataset comprises the locations of outcrops with respective information on the lithology, stratigraphy, rock age and tectonic data collected during the CASE expeditions. The data attributes include stereographic projections and sketches of tectonic structures derived from the outcrop data. At the end of the 1980s, BGR initiated the research program Circum-Arctic Structural Events (CASE) to reconstruct the plate tectonic processes during the evolution of the Arctic Ocean using terrestrial data from the surrounding continental margins. One of the scientific questions of the CASE programme is as simple as it is complex: How did the Arctic Ocean, this large basin between the Eurasian and North American continental plates, develop? There are still no conclusive answers to this question in terms of plate tectonics. In contrast to the marine expeditions of geophysicists in the Arctic Ocean, geologists on land along the various coastal areas of the Arctic Ocean can directly touch, examine and map rocks, structures, folds and fault zones and determine the respective ages of the movements. This makes it possible to directly compare rock units and deformation zones on different continental plates and thus also to reconstruct when these plates collided, how long they remained next to each other and when and how they separated again. Since the inception of BGR’s Arctic research, the primary focus and research areas have been along the continental margins between Spitsbergen and the Canadian Arctic Archipelago via Greenland, to the Yukon North Slope on the border with Alaska. On the opposite side of the Arctic Ocean, there have been expeditions to Yakutia, the mainland areas near the Laptev Sea, the New Siberian Islands and to the Polar Ural with Russian partners. An important method for the interpretation of the geological evolution of the Arctic is the examination of tectonic structures (faults, folds, cleavage etc.), the determination of the kinematics and the age of the tectonic movements.
Indikator: Ökologischer Zustand der Übergangs- und Küstengewässer Die wichtigsten Fakten Kein einziges Gebiet ( Wasserkörper ) der Übergangs- und Küstengewässer in Nord- und Ostsee war 2021 in gutem oder sehr gutem Zustand. Laut europäischer Wasserrahmenrichtlinie sollten bis zum Jahr 2015 mit Fristverlängerung bis 2027 alle Gewässer mindestens in einem guten ökologischen Zustand sein. Es gilt nun die Zeit bis spätestens 2027 zu nutzen, um die anspruchsvollen Ziele zu erreichen. Dazu sind weitere erhebliche Anstrengungen erforderlich. Welche Bedeutung hat der Indikator? Die hohe Zufuhr von Nährstoffen wie Stickstoff und Phosphor in Nord- und Ostsee führt zu einem starken Wachstum von Algen. Eine hohe Algendichte führt zu Lichtmangel in tieferen Wasserschichten. Auf Licht angewiesene Pflanzen werden verdrängt. Sterben die Algen und Pflanzen ab, werden sie von Mikroorganismen abgebaut. Bei diesen Vorgängen wird Sauerstoff verbraucht, der Sauerstoffgehalt im Wasser nimmt ab. In der Folge können Tiere ersticken. In der Ostsee sind mittlerweile große Gebiete sauerstoffarm oder sauerstofffrei. In Bezug auf den Nährstoff- und Sauerstoffgehalt unterscheiden sich Ost- und Nordsee deutlich. Die Nordsee tauscht mit dem Atlantischen Ozean und dem Nordpolarmeer ständig Wasser aus und ist insgesamt turbulenter. Die Ostsee steht hingegen nur mit der Nordsee in Verbindung, die Verbindungswege sind sehr schmal. Sie hat daher den Charakter eines Binnenmeeres und reagiert empfindlicher auf zu hohe Nährstoffeinträge. Wie ist die Entwicklung zu bewerten? Von den Küsten- und Übergangsgewässern der Nord- und Ostsee war 2021 kein einziges Gebiet ( Wasserkörper ) in „gutem“ oder „sehr gutem“ ökologischen Zustand. Damit wurde das Ziel der europäischen Wasserrahmenrichtlinie (WRRL, EU-RL 2000/60/EG) drastisch verfehlt, dass alle Gewässer bis 2015 mindestens in einem guten ökologischen Zustand sein müssen. Da dieses Ziel klar verfehlt wurde, gab es eine Fristverlängerung bis 2027 und es gilt den gemäß WRRL nächsten Bewirtschaftungszyklus zu nutzen, um bis dahin die anspruchsvollen Ziele zu erreichen. Der Grund für das Verfehlen der Ziele ist vor allem der übermäßige Eintrag von Nährstoffen in die Küsten- und Übergangsgewässer ( Eutrophierung ). Diese stammen vorwiegend aus der Landwirtschaft, aus Kläranlagen und der Schifffahrt. Die Nährstoffe werden über Flüsse oder die Atmosphäre in die Meere eingetragen (siehe Indikatoren „Eutrophierung von Nord- und Ostsee durch Stickstoff“ und „Eutrophierung von Flüssen durch Phosphor“ ). Bislang ergriffene Maßnahmen greifen (noch) nicht im geforderten Maße. Um die Nährstoffeinträge so weit zu verringern, dass der gute Zustand erreicht werden kann, müssen die Anstrengungen deshalb deutlich verstärkt werden. In beiden Meeren hat sich der Anteil „schlechter“ und „unbefriedigender“ Gebiete gegenüber 2015 erhöht. Dies lässt sich vor allem durch eine deutlich verbesserte Datenlage und geänderte Schwellenwerte für die Bewertung erklären. Real hat sich der Zustand kaum verschlechtert. Wie wird der Indikator berechnet? Um den ökologischen Zustand eines Küsten- und Übergangsgewässers zu bestimmen, wird vor allem die Artenzusammensetzung ausgewählter pflanzlicher und tierischer Lebensgemeinschaften mit Zeigerwirkung analysiert: Wie weit entspricht sie der typischen Zusammensetzung des jeweiligen Naturraumes? Je nach Grad der Abweichung vom natürlichen Zustand werden fünf Zustandsklassen zugeordnet: von „sehr gut“ bis „schlecht“. Eine ausführliche Beschreibung zur Gewässerbewertung wurde von Voß et al. (2010) veröffentlicht. Ausführliche Informationen zum Thema finden Sie in den Daten-Artikeln „Ökologischer Zustand der Küstengewässer der Nordsee“ und „Ökologischer Zustand der Küstengewässer der Ostsee“ .
During the period from 1974 to 2018 various cruises from BGR acquired seismic lines worldwide. The aim of these marine expeditions was a detailed survey of the geological structure.
The expedition PS155/1 started on August 5th, 2018 in Tromsø (Norway) and ended in Longyearbyen (Spitsbergen) on September 3rd, 2018. In the course of BGR’s GREENMATE project the geological development of the European North Atlantic and the northern and north eastern Greenland shelf was analyzed using various marine geophysical methods (seismics, magnetics, gravity, heatflow measurements) and geological sampling (gravity corer, box corer, multi-corer, dredge). Sampling of marine Shelf sediments was undertaken in close correspondence with co-users from Geomar (add-on project ECHONEG), aiming to reconstruct Holocene paleo environmental and climatic evolution. Using the ship’s helicopters, marine sampling was complemented by onshore sampling operations to extract geological material at selected near coastal locations. Other scientific project groups used the cruise PS115.1 as an opportunity to quantify marine mammals and sea birds and their statistical distribution in our research area as part of the long-term project (add-on project Birds& Mammals) and to gather additional meteorological data via radiosondes (add-on Project YOPP). Against all expectations, outstanding ice conditions along the northern coast of Greenland enabled us to carry out reflection seismic surveys north of 84°N at the southern tip of Morris Jesup Rise with a 3 km long streamer. Structural data of this particular region of North Greenland is of special importance for BGR’s project GREENMATE for reconstructing the continental margin evolution. A 100 km long refraction seismic profile was measured to complement the reflection seismic data. After completing this, scientific work was concentrated on the northeastern Greenland shelf area between 76°N and 82.5°N. Over the time of the cruise a total of 2500 km of reflection seismic profiles (2250 km measured with 3km streamer length) and 100 km of refraction seismic profile (using nine ocean bottom seismometers) were measured, accompanied by gravity and magnetic surveys and seven heat flow measurement stations. Along the shelf and deep-sea area 21 geological sampling sites were chosen, with all together one dredge (around 200 kg of sample), 16 gravity cores (total core length 65 m), 12 box corers and 6 multi-corer stations. Onshore sediment sampling was done at 11 sampling sites. Beside sediment sampling hard rock from near coastal outcrops was collected in a total amount of 250 kg that will be used for age dating. The entire science program was carried out under consideration of the highest ecological standards to protect marine mammals and to meet all environmental requirements of the permitting authorities. In addition to external marine mammal observers (MMO) various acoustic monitoring systems and AWI’s on board infrared detection system AIMMS monitored any activity of marine mammals in the ships perimeter, especially during seismic operations.
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