Helge Wolfgang Arz

Leibniz Institute for Baltic Sea Research | IOW · Marine Geology

Pio XI Glacier (49°S) is the largest and one of the very few advancing glaciers in Patagonia. Satellite data indicate that the main glacier terminus transitioned from calving to land-based around 2010, effectively resulting in the formation of an ice-contact delta at the head of Eyre Fjord. Here, we investigate how this ice-contact delta formation...

Our understanding of glacial isostatic rebound across Patagonia is highly limited, despite its importance to constrain past ice volume estimates and better comprehend relative sea-level variations. With this in mind, our research objective is to reconstruct the magnitude and rate of Late Glacial and Holocene glacial isostatic adjustment near the ce...

Southern Ocean deep-water circulation plays an important role in the global carbon cycle. On geological time-scales, upwelling along the Chilean continental margin likely contributed to the deglacial atmospheric carbon dioxide rise, but little quantitative evidence exists of carbon storage. Here, we use a new X-ray Micro-Computer-Tomography method...

The Antarctic Circumpolar Current (ACC) plays a crucial role in global ocean circulation by fostering deep-water upwelling and formation of new water masses. On geological time-scales, ACC variations are poorly constrained beyond the last glacial. Here, we reconstruct changes in ACC strength in the central Drake Passage over the past 140,000 years,...

The Mono Lake geomagnetic excursion, characterized by low paleointensity and excursional virtual geomagnetic pole (VGP) positions at about 35 ka, has been cumulatively documented from global sites. However, the geomagnetic field geometry during this short-lived excursion is not conclusively described, since excursional directions are only sporadica...

A comprehensive magnetostratigraphic investigation on sixteen sediment cores from the southeastern Black Sea yielded a very detailed high-quality paleosecular variation (PSV) record spanning from 20 to 15 ka. The age models are based on radiocarbon dating, stratigraphic correlation, and tephrochronology. Further age constraints were obtained by cor...

Pockmarks are variably sized crater-like structures that occur in young continental margin sediments. They are formed by gas eruptions and/or long-term release of fluid or gas. So far no pockmarks were known from the Pacific coast of South America between 51°S and 55°S. This article documents an extensive and previously unknown pockmark field in th...

A total of nine sediment cores recovered from the Archangelsky Ridge in the SE Black Sea were systematically subjected to intense paleo- and mineral magnetic analyses. Besides 16 accelerator mass spectrometry (AMS) ¹⁴C ages available for another core from this area, dating was accomplished by correlation of short-term warming events during the last...

The transition from hunter-gatherer-fisher groups to agrarian societies is arguably the most significant change in human prehistory. In the European plain there is evidence for fully developed agrarian societies by 7,500 cal. yr BP, yet a well-established agrarian society does not appear in the north until 6,000 cal. yr BP for unknown reasons. Here...

Reconstructions of environmental changes at sub-decadal to decadal resolution based on central Baltic Sea sediments rely on accurate and precise high-resolution sediment depth/age relationships. A model chronology for Baltic Sea sediments is presented here based on established historical records of anthropogenic radionuclides (137Cs/241Am/bomb14C),...

The Littorina Sea stage (past c. 7000 years) development of the northern, and its interactions with the central Baltic Sea have been influenced by spatially different but in the north very strong glacio-isostatic uplift. Here we investigate the impact of the isostatic readjustment on the northern Baltic Sea environment and on the water exchange wit...

Lake Salda located in south-western Anatolia is characterized by the presence of living stromatolites and by a low diversity of both phytoplankton and zooplankton due to high pH and magnesium concentration. The most abundant, free sedimentary lipids of the uppermost centimetres of the lake sediments were studied as potential environmental biomarker...

Acoustic profiling methods are commonly used in the geosciences to obtain knowledge about the sedimentary structures of marine deposits. However, their interpretation and the correlation of acoustic reflectors with sedimentological boundaries remain difficult. The gradient in acoustic impedance determines the intensity of acoustic reflectors, which...

The Marine Isotope Stage (MIS) 3 stands out due to its abrupt changes from cold and dry stadials to warm and humid interstadials, the so-called Dansgaard-Oeschger cycles that also affected temperature and rainfall in the Black Sea region. This study is based on a gravity core from the southeastern (SE) Black Sea that covers the last glacial lake st...

The Baltic Sea is a shallow, semi-enclosed and intra-continental shelf sea characterized by anoxic bottom waters in the deepest basins, allowing for the preservation of sedimentary organic matter. In the present study, the most abundant, naturally-occurring lipids in surface sediments from the entire Baltic Sea and the Skagerrak area were identifie...

C25 and C30 highly branched isoprenoid (HBI) alkenes are lipid biomarkers produced exclusively by certain diatoms and found in sediments worldwide. Here, for the first time, it is shown that the marine planktonic diatom Pseudosolenia calcar-avis (Schultze) (Sundström, B.G., 1986. The Marine Diatom Genus Rhizosolenia (A New Approach to the Taxonomy)...

During the last glacial termination, the upper North Pacific Ocean underwent dramatic and rapid changes in oxygenation that lead to the transient intensification of oxygen minimum zones (OMZs), recorded by the widespread occurrence of laminated sediments on circum-Pacific continental margins. We present a new laminated sediment record from the mid-...

This study provides the first detailed multi-proxy paleoenvironmental reconstructions of changes in the aquatic and terrestrial ecosystems during the Holocene, Eemian and the last two glacial/interglacial transitions (Terminations I and II) by studying sediment cores from the southeastern Black Sea and stalagmite studies from Sofular Cave in northw...

The Eurasian inland propagation of temperature anomalies during glacial millennial-scale climate variability is poorly understood but this knowledge is crucial to understanding hemisphere-wide atmospheric teleconnection patterns and climate mechanisms. Based on biomarkers and geochemical paleothermometers, a pronounced continental temperature varia...

Proxies based on glycerol dialkyl glycerol tetraether (GDGT) lipids from archaea [isoprenoid GDGTs] and bacteria [branched (br) GDGTs] in 33 surface sediments from marine, fjord and lake systems between 25°S and 50°S in Chile were analyzed. The regional TEXH86 calibration obtained from the marine and fjord sediments and mean annual surface temperat...

Significance The Drake Passage (DP) represents the most important oceanic gateway along the pathway of the world’s largest current: the Antarctic Circumpolar Current (ACC). Resolving changes in the flow of circumpolar water masses through the DP is crucial for advancing our understanding of the Southern Ocean’s role in affecting ocean and climate c...

Based on results of geochemical and radionuclide measurements, indicators for possible causes of sediment dynamics and mixing in the Mecklenburg Bight and the Arkona Basin are investigated. Instead of expected sharp 137Cs peaks and characteristic Hg profiles the data often show blurred signals that sometimes even match each other indicating varying...

Küsten- und Randmeere dienen als natürliche Umsatz- und Lagerstätten für landseitige Einträge. Der Hauptort für die Modifikation und die Ablagerung der eingebrachten Stoffe sind in den meisten Fällen nicht die Wassermassen der Rand- und Nebenmeere, sondern die Sedimente, deren Schlüsselfunktion als zentrale Reaktoren in der Wechselwirkung zwischen...

Acoustic profiling methods are widely used to provide a rapid view into geological structures. For the interpretation of acoustic profiling results (single- and multi-beam), reliable geo-acoustic models are needed. Suitable geo-acoustic models covering a wide range of sediment types do not exist to date for the Baltic Sea. Based on surface sediment...

The Eurasian inland propagation of temperature anomalies during glacial millennial-scale climate variability is poorly understood but this knowledge is crucial to understanding hemisphere-wide atmospheric teleconnection patterns and climate mechanisms. Based on biomarkers and geochemical paleothermometers, a pronounced continental temperature varia...

The Drake Passage (DP) is the major geographic constriction for the Antarctic Circumpolar Current (ACC) and exerts a strong control on the exchange of physical, chemical, and biological properties between the Atlantic, Pacific, and Indian Ocean basins. Resolving changes in the flow of circumpolar water masses through this gateway is, therefore, cru...

This project aimed at investigating centennial to millennial-scale changes of the strength and position of the southern westerly wind belt (SWW) using multi-proxy paleoprecipitation and paleoceanographic records combined with transient model runs. The proxy data records reveal a distinct latitudinal anti-phasing of wind changes between the core and...

During the last glacial termination, the upper North Pacific Ocean underwent dramatic and rapid changes in oxygenation that lead to the transient intensification of oxygen minimum zones (OMZs), recorded by the widespread occurrence of laminated sediments on circum-Pacific continental margins. We present a new laminated sediment record from the mid-...

During the last glacial termination, the upper North Pacific Ocean underwent dramatic and rapid changes in oxygenation that lead to the transient intensification of oxygen minimum zones (OMZs), recorded by the widespread occurrence of laminated sediments on circum-Pacific continental margins. We present a new laminated sediment record from the mid-...

One visible volcanic ash layer and 21 non-visible, cryptotephra horizons have been identified in the M72/5-25-GC1 core from the south-east Black Sea that spans the last ∼60 ka. Glass chemistry suggests that the tephras derive from Italian, Hellenic and Turkish sources. The visible tephra layer is trachytic in composition and has been correlated to...

In order to investigate sedimentation processes, short sediment cores from the Mecklenburg Bight and the Arkona Basin are analysed for sediment properties (grain size, water content, dry bulk density), selected chemical parameters (Hg, TOC, TIC, TN) and radionuclides (137Cs and 210Pb). Key issues that need to be considered for the interpretation of...

Here we provide three new Holocene (11–0 cal ka BP) alkenone-derived sea surface temperature (SST) records from the southernmost Chilean fjord region (50–53°S). SST estimates may be biased towards summer temperature in this region, as revealed by a large set of surface sediments. The Holocene records show consistently warmer than present-day SSTs e...

A series of molecular organic markers were determined in surface sediments from the Gulf of Genoa (Ligurian Sea) in order to evaluate their potential for palaeo-environmental reconstructions. Allochthonous input can be characterized by the distributions of n-C29 and n-C31 alkanes, n-C26 and n-C28 alkanols and branched glycerol dialkyl glycerol tetr...

During the last glacial termination, the upper North Pacific Ocean underwent dramatic and rapid changes in oxygenation that lead to the transient intensification of Oxygen Minimum Zones (OMZs), recorded by the widespread occurrence of laminated sediments on circum-Pacific continental margins. We present a new laminated sediment record from the mid-...

High-resolution pollen and dinoflagellate cyst records from sediment core M72/5-25-GC1 were used to reconstruct vegetation dynamics in northern Anatolia and surface conditions of the Black Sea between 64 and 20 ka BP. During this period, the dominance of Artemisia in the pollen record indicates a steppe landscape and arid climate conditions. Howeve...

A series of molecular organic markers were determined in surface sediments from the Gulf of Genoa (Ligurian Sea) in order to evaluate their potential for palaeo-environmental reconstructions. Allochthonous input can be characterized by the distributions of n-C29 and n-C31 alkanes, n-C26 and n-C28 alkanols and branched glycerol dialkyl glycerol tetr...

The last glacial-interglacial transition or Termination I (T I) is well documented in the Black Sea, whereas little is known about climate and environmental dynamics during the penultimate Termination (T II). Here we present a multi-proxy study based on a sediment core from the SE Black Sea covering the penultimate glacial and almost the entire Eem...

Detailed paleo- and mineral magnetic analyses of a sediment composite record from the southeastern Black Sea yielded a high-resolution, well-dated paleointensity record. Though hampered by some larger hiatuses in some cores, and contaminated by diagenetically formed greigite, the paleomagnetic composite record obtained from the preserved primary de...

This multiproxy study on SE Black Sea sediments provides the first detailed reconstruction of vegetation and environmental history of Northern Anatolia between 134 and 119 ka. Here, the glacial–interglacial transition is characterized by several short-lived alternating cold and warm events preceding a meltwater pulse (~ 130.4–131.7 ka). The latter...

High-resolution pollen and dinoflagellate cyst records from marine sediment core 25-GC1 were used to reconstruct vegetation dynamics in Northern Anatolia and surface conditions of the Black Sea between 64 and 25 ka BP. During this period, the dominance of Artemisia in the pollen record indicates a steppe landscape and arid climate conditions. Howev...

The southern tip of South America is year-round influenced by the southern westerly wind belt (SWW) causing extremely high precipitation along the Chilean coast and the Andes south of 33°S with maximum values of 3000 to >10 000 mm/year within the SWW core between 49 to 55°S which is unique for temperate regions on the global scale. Due to this key...

Holocene denudation rates and their regional variations in the superhumid and temperate climate of the southernmost Patagonian Andes are poorly surveyed. Therefore we have investigated denudation in five small lake catchments (0.11–1.62 km2) across a precipitation gradient from 600 to > 9000 mm yr− 1 in southernmost Chile at 53°S. Variations in den...

Detailed stratigraphic analyses of a sediment composite record from three different sites in the southeastern Black Sea yielded a high-resolution, well-dated paleomagnetic record of the past 14 to 68 ka. Age constraints are provided by 16 AMS 14C ages, identification of the Campanian Ignimbrite tephra (39.28±0.11 ka), and by detailed tuning of sedi...

In order to improve the knowledge about regional climate development in the Eastern Mediterranean, the DFG-Project "Dynamics of Mid-latitude / Mediterranean climate during the last 150 ka: Black Sea / Northern Anatolian Paleoenvironmental Reconstructions" (DynNAP) was established. For this goal, marine cores 22-GC3 and 22-GC8 from SE Black Sea cove...

The currently euxinic deeps of the central Baltic Sea are hotspots of intense microbial activity and biogeochemical cycling of nutrients and redox-sensitive elements. A prominent feature forms the pelagic redoxcline separating oxic surface from H2S containing bottom waters. This transition zone is characterized by steep gradients of various compone...

The epicontinental Black Sea is very sensitive to environmental changes thus forming an ideal archive of regional climate change and teleconnective responses to the coupled North Atlantic ocean-atmosphere system. Here we focus on the climatic and hydrological evolution of the SE Black Sea during the glacial-interglacial transition of Termination II...

In order to compare the sea-surface conditions in the Black Sea during the Holocene and Eemian, sapropelic parts of marine core 22-GC3 (42 degrees 13.53'N/36 degrees 29.55'E, 838 m water depth) were studied for organic-walled dinoflagellate cyst content. The record shows a change from freshwater/brackish assemblages (Pyxidinopsis psilata, Spiniferi...

10 RESUMEN Los sistemas de terrazas evidencian que el Seno Otway y Skyring y el fiordo de Última Esperanza, formaron el mayor sistema lacustre proglacial interconectado de la Patagonia Austral (5.700 km 2) durante la deglaciación temprana (< 18 a 14 ka BP). Este sistema drenaba por el este del Seno Otway hacia el Atlántico. El retroceso de los glac...

Investigated sediment cores from the southeastern Black Sea provide a high-resolution record from mid latitudes of the Laschamp geomagnetic polarity excursion. Age constraints are provided by 16 AMS 14C ages, identification of the Campanian Ignimbrite tephra (39.28±0.11 ka), and by detailed tuning of sedimentologic parameters of the Black Sea sedim...

Cited By (since 1996): 1, Export Date: 6 February 2013, Source: Scopus

There is ongoing debate about the relative influence of aquatic production, flux, and sedimentation of aquatic and terrestrial organic matter on mercury accumulation in lake sediments. In this study, lake sediments spanning the past 4,250 years, were collected from remote, organic-rich Lake Hambre, Patagonia (53° S) and investigated for changes in...

The Southern Patagonian Icefield (PIF) constitutes the largest continental ice-sheet outside the polar regions. Its Holocene glacier fluctuations and their forcing mechanism are still poorly explored, especially on the western hyperhumid side of the Andes. Glacier fluctuations have been previously constrained by 14C and/or cosmogenic ages of morain...

Sediments from the Black Sea, a region historically dominated by forests and steppe landscapes, are a valuable source of detailed information on the changes in regional terrestrial and aquatic environments at decadal to millennial scales. Here we present multi-proxy environmental records (pollen, dinoflagellate cysts, Ca, Ti and oxygen isotope data...

The supply of nutrients to the low-latitude thermocline is largely controlled by intermediate-depth waters formed at the surface in the high southern latitudes. Silicic acid is an essential macronutrient for diatoms, which are responsible for a significant portion of marine carbon export production. Changes in ocean circulation, such as those obser...

Investigated sediment cores from the southeastern Black Sea provide a high-resolution record from mid latitudes of the Laschamp geomagnetic polarity excursion. Age constraints are provided by 16 AMS 14C ages, identification of the Campanian Ignimbrite tephra (39.28±0.11 ka), and by detailed tuning of sedimentologic parameters of the Black Sea sedim...

Between ca. 17.8 and 14.6 cal kyr BP an abrupt atmospheric CO2 rise seems to have played a pivotal role on the last termination. One hypothesis claims that the ca. 50 ppmv added to the atmosphere during the early termination came from a deep-ocean reservoir and reached the atmosphere via enhanced upwelling in the Southern Ocean. In this scenario, t...

During the RV Sonne expedition SO202-INOPEX, sediment cores containing laminated sequences were collected from the Bowers Ridge, the Umnak Plateau and from the Bering Sea continental slope. The extensive occurrence of laminated sediments throughout the Bering Sea suggests that dysoxic conditions were comparatively widespread in this region. Previou...

Glacial millennial-scale paleoceanographic changes in the Southeast Pacific and the adjacent Southern Ocean are poorly known due to the scarcity of well-dated and high resolution sediment records. Here we present new surface water records from sediment core MD07-3128 recovered at 53°S off the Pacific entrance of the Strait of Magellan. The alkenone...

The supply of nutrients to the low-latitude thermocline is largely controlled by intermediate-depth waters formed at the surface in the high southern latitudes. Silicic acid is an essential macronutrient for diatoms, which are responsible for a significant portion of marine carbon export production. Changes in ocean circulation, such as those obser...

Glacial millennial-scale paleoceanographic changes in the Southeast Pacific and the adjacent Southern Ocean are poorly known due to the scarcity of well-dated and high resolution sediment records. Here we present new surface water records from sediment core MD07-3128 recovered at 53°S off the Pacific entrance of the Strait of Magellan. The alkenone...

Understanding the dynamics of the Southern Westerlies wind belt (SWW) on different timescales is crucial since the SWW plays a major role in controlling the Antarctic Circumpolar Current and global thermohaline circulation. Despite this importance, there are still uncertainties about Holocene changes of the SWW. The southern Chilean fjord system be...

During R/V Meteor expedition M72/5 in 2007, two gravity cores (22-GC-7/3) were recovered which contain a second sapropel 7 m beneath the recent (Holocene) one. Both sapropels were sub-sampled on millimeter scale and analyzed by XRF, ICP-OES and HR-ICP-MS for major and trace elements. Additionally, samples of the second sapropel were analyzed for U...

Cenozoic denudation rates are sparsely known for the southernmost Patagonian Andes. One of the scientific approaches is to calculate long-term denudation rates based on fission track analyses. Though, these average rates comprise a long period with distinct climate conditions and very different extend of glaciation. These integrated denudation rate...

Quantification of the spatial enhancement of ocean anoxia during Mesozoic OAEs using Mo and U isotope signatures

We present new paleoceanographic data from a sediment core MD07-3128 recovered during IMAGES XV-MD159-PACHIDERME cruise off southernmost Chile. The coring site is located at 53°S on the continental slope (~1000 m water depth) off the Pacific entrance of the Strait of Magellan. The alkenone-derived SST record reveals a very strong warming of ca. 8 °...

Stalagmites of the superhumid southern Andes are occasionally formed in small non-carst caves in a metamorphic and/or granitoid basement. They originate from coastal erosion in fracture zones during periods of higher sea levels. These small and relatively open caves are equilibrated with outside temperatures. Their drip rates reflect regional preci...

The position and intensity of the southern westerly wind belt varies seasonally as a consequence of changes in sea surface temperature. During the austral winter, the belt expands northward and the wind intensity in the core decreases. Conversely, during the summer, the belt contracts, and the intensity within the core is strengthened. Reconstructi...