Kasia K Śliwińska

• PhD
• Senior Researcher at Geological Survey of Denmark and Greenland

The early Oligocene interval in several boreholes from the eastern North Sea and Denmark has been studied for dinoflagellate cysts. The cold water dinoflagellate cyst Svalbardella cooksoniae was recorded in a narrow lowermost Oligocene interval in all offshore sections. A critical evaluation of previous records of Svalbardella cooksoniae reveals th...

The onset of the North Atlantic Deep Water formation is thought to have coincided with Antarctic ice-sheet growth about 34 million years ago (Ma). However, this timing is debated, in part due to questions over the geochemical signature of the ancient Northern Component Water (NCW) formed in the deep North Atlantic. Here we present detailed geochemi...

During the late Eocene, the Earth’s climate experienced several transient temperature fluctuations including the Vonhof cooling event (C16n.1n; ~35.8 Ma) hitherto known mainly from the southern oceans. Here we reconstruct sea-surface temperatures (SST) and provide δ18O and δ13C foraminiferal records for the late Eocene and earliest Oligocene in the...

A multidisciplinary study of the Oligocene/Miocene (O/M) transition was carried in two boreholes (Harre-1 and Horn-1) from the Danish land area in order to improve the understanding of the paleoclimatological and environmental changes across the Mi-1 the earliest Miocene cooling event. Dinoflagellate cyst (dinocyst) biostratigraphy, supported by re...

The focus of this study is the lower Eocene to lower Miocene succession in ODP Site 643A. The site is located in the Norwegian Sea, at the base of the Outer Vøring Plateau (OVP). We analysed dinocyst assemblages and calculated the relative input of soil organic matter using an organic proxy, the branched/isoprenoid tetraether (BIT) index. Our resul...

Marine glycerol dialkyl glycerol tetraethers (GDGTs) are used in various proxies (such as TEX86) to reconstruct past ocean temperatures. Over 20 years of improvements in GDGT sample processing, analytical techniques, data interpretation and our understanding of proxy functioning have led to the collective development of a set of best practices in a...

Sedimentary rocks can provide information about the Earth paleoenvironment and are studied extensively to understand the causes and consequences of global climate changes in deep time. They facilitate long-time perspectives that constrain climate models and provide analogues for how Earth systems may respond to, and recover from, intervals of profo...

A rich late Oligocene molluscan fauna from a coastal cliff at Vilsund on the island of Mors, Jylland, Denmark, was studied. A summary of the upper Palaeogene sedimentary sequence in NW Jylland is given and lithostratigraphical and biostratigraphical correlations are suggested. The molluscan fauna contains 120 species, and the nonmolluscs are briefl...

Despite often being referred to as a ‘coolhouse climate’, the climate during the Miocene (23.03–5.33 Ma) was overall humid, warm and temperate. It was paced by orbitally driven cooler periods (the Oligocene–Miocene Transition and Mi-events) overprinted by a climatic optimum. Global cooling during the Late Miocene brought more arid conditions with c...

Lower Cretaceous stratigraphy of the high palaeo-latitude Arctic-Boreal Realm is generally more poorly understood than its lower-latitude Tethyan counterpart, prohibiting regional correlations and evaluation of global climate dynamics during this important high- p CO 2 period. In this paper, a holostratigraphic scheme and lithostratigraphic revisio...

A rich late Oligocene molluscan fauna from a coastal cliff at Vilsund on the island of Mors, Jylland, Denmark, was studied. A summary of the upper Palaeogene sedimentary sequence in NW Jylland is given and lithostratigraphical and biostratigraphical correlations are suggested. The molluscan fauna contains 120 species, and the nonmolluscs are briefl...

The type locality for the upper Oligocene Nuwok Member of the Sagavanirktok Formation (Carter Creek, North Slope, Alaska, USA) contains abundant occurrence of glendonite, a pseudomorph after the calcium carbonate mineral ikaite, which typically forms in the shallow subsurface of cold marine sediments. The region during the time of Nuwok Member depo...

We held the MagellanPlus workshop SVALCLIME “Deep-time Arctic climate archives: high-resolution coring of Svalbard's sedimentary record”, from 18 to 21 October 2022 in Longyearbyen, to discuss scientific drilling of the unique high-resolution climate archives of Neoproterozoic to Paleogene age present in the sedimentary record of Svalbard. Svalbard...

Acritarchs are an informal, polyphyletic, and morphologically heterogenous group of organic-walled microfossils of unknown biological affinity. Some acritarchs share morphological similarities with certain microplankton resting stages (from e.g., dinoflagellates, prasinophycean-, chlorophycean-, and zygnematophycean green algae), others with miospo...

The Oligocene epoch is characterized by a coolhouse climate, paced by several cooling episodes. The few existing proxy records suggest that during the Oligocene the latitudinal temperature gradient increased, when compared to the warmer Eocene. However, the number of Oligocene temperature records from northern latitudes above 50 °N is very limited....

The Miocene Climatic Optimum (∼16.9-14.7 Ma) was the most recent interval in Earth history with atmospheric CO 2 concentrations above ∼400 ppm. The climatic optimum is associated with elevated temperatures, especially in the middle and higher latitudes. However, existing temperature records, especially from northern high-mid latitudes, are relative...

When a permanent ice cap developed on Antarctica during the Eocene–Oligocene transition (EOT; ~34.44 to 33.65 million years ago (Ma)), Earth witnessed a transition from a greenhouse towards a glacially driven climate. Evidence of high-latitude cooling and increased latitudinal temperature gradients across the EOT has been found in both marine and t...

The Miocene Climatic Optimum (~17 to 14 Million years ago) has recently gained attention as a future climate analogue. However, the number of climatic records from the northern high and middle latitudes is very limited, so the global impact across this climatic transition is still poorly understood. The most northernly located site penetrating a ne...

Since 1976 more than 25,000 Arctic sediment samples have been processed for their palynological, nannofossil, or microfossil content at the Geological Survey of Greenland (GGU) and the Geological Survey of Denmark (DGU); both institutes are now merged into the Geological Survey of Denmark and Greenland (GEUS). The samples represent nearly all ages...

A major step in the long-term Cenozoic evolution toward a glacially driven climate occurred at the Eocene–Oligocene transition (EOT), ∼34.44 to 33.65 million years ago (Ma). Evidence for high-latitude cooling and increased latitudinal temperature gradients across the EOT has been found in a range of marine and terrestrial environments. However, the...

A new Pentaplacodinium species with six precingular plates is described from Bahía Concepción and Bahía de la Paz, Gulf of California. The non-fossil motile stage is described as Pentaplacodinium lapazense, whilst the fossil stage is described as Operculodinium lapazense. The cyst morphology is compared to topotype material of Operculodinium israel...

The Miocene Climatic Optimum (~16.9-14.7 Ma) was the most recent interval in Earth's history with greenhouse conditions, which prevailed for nearly 2 million years. The optimum was associated with elevated atmospheric CO 2 (~400-600 ppm) and higher global temperatures, and therefore the optimum is considered one of the best analogues for future cli...

The Eocene Oligocene Transition (EOT) 34 million years ago (Ma), was characterized by a climate shift from a largely ice-free greenhouse world to an icehouse climate. The colder Oligocene period included several cooling episodes, defining the bases of a s-Atlantic region, some of these cooling episodes are associated with appearance intervals of th...

An appraisal of ancient Earth’s climate dynamics is crucial for understanding the modern climate system and predicting how this might change in the future. Major climate-shift events in the Earth’s past demonstrate the scale, duration and response of the climate system to various global and local climate stressors. More than 650 million years of...

A major step in the long-term Cenozoic evolution toward a glacially-driven climate occurred at the Eocene Oligocene Transition (EOT), ~34.44 to 33.65 million years ago (Ma). Evidence for high latitude cooling and increased latitudinal temperature gradients across the EOT has been found in a range of marine and terrestrial environments. However, the...

Eleven cored boreholes, with depths up to c. 360 m were drilled in north-east Baffin Bay, a frontier area offshore West Greenland by the vessel Joides Resolution. The cores were part of the Baffin Bay scientific shallow coring program, expedition 344S in 2012, funded by a consortium of eight petroleum companies. The main drilling target was a succe...

The Carolinefjellet Formation is an Aptian–Albian marine succession on Spitsbergen (Svalbard, Arctic Norway). The formation comprises five intercalated sandstone and mudstone-dominated members, whereby the upper two have informal member status: the Zillerberget and the Schönrockfjellet members. Their informal member status is partly due to uncertai...

The Miocene climate was dynamic, oscillating between major glaciation events and greenhouse conditions (the so-called Miocene Climatic Optimum or MCO). However, forcing factors responsible for climatic transitions from one state to another are not fully understood, partly because palaeoclimatological records from northern mid to high latitudes are...

Here, we present an updated stratigraphic subdivision of the Oligocene to Pleistocene succession (880–610 m) in the newly proposed type well for the Molo Formation, the industrial 6407/9‐5 well, located on the continental shelf in the eastern Norwegian Sea. Furthermore, new data from the Danish North Sea wells Nora‐1, Vagn‐2, and Tove‐1 are present...

The Eocene–Oligocene transition (EOT) was a climate shift from a largely ice-free greenhouse world to an icehouse climate, involving the first major glaciation of Antarctica and global cooling occurring ∼34 million years ago (Ma) and lasting ∼790 kyr. The change is marked by a global shift in deep-sea δ18O representing a combination of deep-ocean c...

The Miocene epoch witnessed major changes in climate. The marine oxygen isotope record, our best single continuous representation of the time interval, contains large shifts indicating substantial changes in the glaciation of Antarctica and/or deep ocean temperatures, with the interval of the most depleted isotopic composition occurring between ~18...

Several studies indicate that North Atlantic Deep Water (NADW) formation might have initiated during the globally warm Eocene (56–34 Ma). However, constraints on Eocene surface ocean conditions in source regions presently conducive to deep water formation are sparse. Here we test whether ocean conditions of the middle Eocene Labrador Sea might have...

Species of the fusiform peridiniacean dinoflagellate cyst genera Svalbardella Manum, 1960, emend. (Eocene–Oligocene) and Palaeocystodinium Alberti, 1961 (Late Cretaceous–Miocene), have been examined from the high to middle latitudes of the Northern Hemisphere: Spitsbergen, Norwegian-Greenland Sea, Labrador Sea, western North Atlantic, and the North...

The dominance of isotropic hummocky cross‐stratification, recording deposition solely by oscillatory flows, in many ancient storm‐dominated shoreface–shelf successions is enigmatic. Based on conventional sedimentological investigations, this study shows that storm deposits in three different and stratigraphically separated siliciclastic sediment we...

Late Jurassic – Early Cretaceous global carbon-cycle dynamics have mainly been inferred from Tethyan, Atlantic and Pacific carbon-isotope (δ13C) records. These records indicate a steady deceleration of the carbon cycle in Late Jurassic and Jurassic–Cretaceous (J–K) boundary times followed by a major mid-Valanginian carbon-cycle perturbation demarca...

Abstract. The Eocene-Oligocene transition (EOT) from a largely ice-free greenhouse world to an icehouse climate with the first major glaciation of Antarctica was a phase of major climate and environmental change occurring ~34 million years ago (Ma) and lasting ~500 kyr. The change is marked by a global shift in deep sea δ¹⁸O representing...

In order to improve the understanding of how the high northern latitudes responded to the escalating warming which led to the middle Cretaceous super greenhouse climate more temperature proxy records from the High Arctic are needed. One of the current obstacles in obtaining such records is poor age control on the Lower Cretaceous strata in the Bore...

Supplementary material to Śliwińska, K., Jelby, M., Grundvåg, S., Nøhr-Hansen, H., Alsen, P., & Olaussen, S. (n.d.). Dinocyst stratigraphy of the Valanginian–Aptian Rurikfjellet and Helvetiafjellet formations on Spitsbergen, Arctic Norway. Geological Magazine, 1-22.

An impact with a dash of volcanism Around the time of the end-Cretaceous mass extinction that wiped out dinosaurs, there was both a bolide impact and a large amount of volcanism. Hull et al. ran several temperature simulations based on different volcanic outgassing scenarios and compared them with temperature records across the extinction event. Th...

The original description of the large and characteristic belemnite species Arctoteuthis bluethgeni Doyle was based on fragmentary material from a relatively uncertain stratigraphic interval in Kong Karls Land, Svalbard. Recent collection of a belemnite assemblage in the Lower Cretaceous Rurikfjellet Formation on Spitsbergen include numerous complet...

The lower Oligocene (Rupelian) successions are climate record archives of the early icehouse world in the Cenozoic. Even though the number of studies focussing on the generally cold Oligocene is increasing, little is known about climatic variations in the mid-latitudes to high latitudes of the Northern Hemisphere. One of the major obstacles is the...

The Lower Cretaceous succession in Svalbard is commonly considered as an important analogue to age-equivalent strata on the Barents Shelf which are sporadically targeted by exploration wells. In this study, the stratigraphic and genetic relationship between the Rurikfjellet (open marine), Helvetiafjellet (paralic) and Carolinefjellet (open marine)...

The generally warm Cretaceous (c. 145-66 Ma) climate culminated in the mid Cretaceous Hot Greenhouse climate (95-85 Ma). Another characteristic feature of the Cretaceous period is a high number of Oceanic Anoxic Events (OAE) related with major carbon cycle perturbations. While the Lower Cretaceous successions from equatorial region and middle latit...

We congratulate Rakociński et al. (2018) on a thorough and interesting study of the uppermost Jurassic and Lower Cretaceous strata of central Spitsbergen. Their work is a welcome addition to our knowledge on this enigmatic transitional interval in Svalbard. However, we are of the opinion that their assignment of their CA section to the Rurikfjellet...

Correct interpretations of depositional environments are fundamental for evaluating the geological history of a sedimentary basin. Palynofacies analyses are a valuable supplement to sedimentological and seismic studies. In order to develop a palynofacies reference dataset for fluvio-deltaic and shelfal successions, a study of the assemblages of sed...

The Jurassic–Cretaceous transition in the Boreal Realm forms a stratigraphically enigmatic interval, primarily due to the lack of a unified chronostratigraphic scheme across the systems boundary. In the Tethyan Realm, numerous Upper Jurassic – Lower Cretaceous sections have been correlated by use of well-documented carbon isotope (δ13C) excursions...

Currently the dinocyst genus Svalbardella is represented by two formally described morphotypes: Svalbardella cooksoniae (type species) and S. partimtabulata. However, anumber of informal Svalbardella-like species have been registered from the northernhemisphere settings. Notably, some of these Svalbardella-like forms show features typicalfor the Pa...

In this study we investigate key factors controlling the rift climax to post-rift marine basin fill. We use two- and three-dimensional seismic data in combination with sedimentological core descriptions from the Hammerfest Basin, southwestern Barents Sea in order to characterize and analyze the tectonostratigraphy and seismic facies of the Lower Cr...

Eleven, fully cored boreholes, with depths up to ~360 meter were drilled in 2012 in the north-east Baffin Bay, offshore West Greenland. The cores have been investigated with the aim to achieve a better understanding of the petroleum system associated with Mesozoic to Early Tertiary rift basins in this frontier area. The sites were cored by JOIDES R...

In this paper we investigate the structural evolution of the northcentral Barents Sea during the Early Cretaceous, and the influence of fault activity on the sedimentation pattern in the area. This is achieved by integrating 2D seismic data, two exploration wells and information of available shallow cores from the Norwegian and Russian sectors. As...

The Lower Cretaceous (Valanginian–Hauterivian) Rurikfjellet Formation in Spitsbergen, Svalbard, forms an up to c. 300 m thick succession of fine-grained shelf and lower shoreface shales, siltstones and sandstones (Dypvik et al. 1991). The formation constitutes the regressive part of an >1000 m thick first-order sequence which formed during a long-t...

An extensive Scismic database covering an area of 100,000 km² (38,610 mi²) and 16 wells are integrated to define a sequence-stratigraphic framework for the Lower Cretaceous succession in the southwestern Barents Sea. Seven sequences (S0-S6) are defined, and the geometry, trajectory, and lateral variability of de-compacted Scismic clinoforms are des...

The Lower Cretaceous succession in the Barents Sea is listed as a potential play model by the Norwegian Petroleum Directorate. Reservoirs may occur in deep to shallow marine clastic wedges located in proximity to palaeo-highs and along basin margins. In addition, shelf-prism-scale clinoforms with high amplitude anomalies in their top- and bottomset...

We have analyzed the distribution of glycerol dialkyl glycerol tetraether lipids (GDGTs) in the Oligocene succession recovered by Integrated Ocean Drilling Program Expedition 342. The two studied sites, U1406 and U1411, penetrate a highly expanded section of the upper Eocene–Oligocene–lower Miocene succession. The branched isoprenoid tetraether (B...

The Oligocene epoch represents a somewhat neglected chapter in paleoclimate and paleoceanographic history, which is at least partially due to the scarcity of complete Oligocene sedimentary archives and poor biostratigraphic age control. Many of the biotic events registered in Oligocene microfossils are strongly diachronous across latitudes as a res...

The taxonomic revision of the dinoflagellate cyst subfamily Wetzelielloideae by Williams et al. (2015) places primary emphasis on the type of archaeopyle, and secondarily on wall ornamentation. Williams et al. (2015) argue that the emphasis placed on the archaeopyle type as taxonomic criterion provides much more clarity for taxonomic differentiatio...

The middle Eocene climatic optimum (MECO, ~40 Ma) was an event of a transient warming that interrupted the long-term cooling trend initiated by the end of the early Eocene. So far in Europe the event is observed only in sediment records from Italy and southern England. Here we investigate an almost 3 m thick (depth 70.5 to 73.5 m) non-to low-calcar...

EXTENDED ABSTRACT: The present work forms part of the LoCrA consortium project (for more details see http://locra.ux.uis.no) which aims to improve the understanding of the Lower Cretaceous basin configuration and depositional history in the High Arctic. The main objective of the biostratigraphical study is to revise and improve the age control of t...

The first known fossil vertebrate found in the Lower Cretaceous of Spitsbergen (Svalbard, Arctic Norway) is presented and described. The specimen, a femur, was collected from the Zillerberget member of the Carolinefjellet Formation at Schönrockfjellet in 1962 and was recently re-discovered. The bone is referred to ?Avialae based on a combination of...

The initial shift out of the early Cenozoic greenhouse and into a glacial icehouse climate occurred during the middle to late Eocene and culminated in the abrupt growth of a continental-scale ice cap on Antarctica, during an episode known as the Oligocene Isotope Event 1 (Oi-1) ∼33.7 Ma. Documenting the patterns of global and regional cooling prior...

The Lower Cretaceous succession of Spitsbergen, Svalbard is divided into three lithostratigraphic units: the Rurikfjellet, Helvetiafjellet and Carolinefjellet formations. The depositional settings for the Lower Cretaceous strata ranged from shallow and open marine (the Rurikfjellet and Carolinefjellet formations) to fluvio-deltaic (the Hel-vetiafje...

In relation to the increased exploration activity in the Barents Sea, the Lower Cretaceous has been resurrected as a potential play model. Several recent wells have targeted Lower Cretaceous clastic wedges with the result of several technical discoveries. Most of these clastic wedges are either of shallow marine or deep marine origin and commonly o...

The Lower Cretaceous strata in Svalbard are divided into the Rurikfjellet, Helvetiafjellet and Carolinefjellet formations. Together, they form a >1000 m thick sequence that records long-term shoreline progradation and back-stepping in response to a full cycle of relative fall and rise in sea-level. The Rurikfjellet Formation (Berriasian–Hauterivian...

The original type section for the Chattian stage is situated in northwestern Germany, that is, in the southern part of the semi-enclosed North Sea Basin. A recent magneto-and biostratigraphic study from the eastern North Sea Basin allows a new correlation to be established between sections in the original Chattian type area and sections in central...

The age of the lithostratigraphic units in the Oligocene succession of Denmark is not well known. In order to remedy this situation, an integrated bio-magnetostratigraphical study of the Rupelian–mid Chattian deposits was carried out on six key sections situated in central Jutland. The studied sections include all previously known lithostratigraphi...

In this paper we investigate the Early Oligocene (Rupelian) high-angle clinoform complex from the western part of the Norwegian–Danish Basin. The study consists of an integrated analysis of 3D seismics, petrophysical well logs and micropaleontological data.A series of erosional features and geometry of prograding units, e.g. the high-angle clinofor...

Here we present the results of a multiproxy study of the uppermost Oligocene to lowermost Miocene succession from the Danish land area. The study includes dinoflagellate cysts (dinocyst) stratigraphy, organic geochemistry, magnetostratigraphy, stable carbon isotope (δ13C) analysis and palynofacies analysis of sediment cores from two boreholes (Harr...

At the Eocene-Oligocene transition the Earth experienced a global cooling, which introduced the modern icehouse climate. Within the generally cold Oligocene epoch at least six major cooling events have been recognized. For some of these events it is estimated that the size of the East Antarctic ice cap was up to 180% of today’s volume. While the cl...

The early Oligocene interval in several boreholes from the North Sea Basin (eastern North Sea and Denmark) has been studied for dinoflagellate cysts. The cold water dinoflagellate cyst Svalbardella cooksoniae was recorded in a narrow, lowermost Oligocene interval in all offshore sections. A critical evaluation of previous records of Svalbardella co...

In the eastern part of the North Sea Basin, including the present Danish land area, the Eocene-Oligocene transition coincides with a major shift in the depositional pattern. Eocene sediments are dominated by hemipelagic clays while Oligocene deposits are characterized by locally distributed, thick, sandy clinoforms, prograding from the north-east....

Integrated micropaleontological (dinoflagellate and foraminifera) and 3D seismic studies of Oligocene surfaces were carried out in the eastern North Sea in order to investigate the influence of the climate on the evolution of depositional geometries and surface morphologies. Age-indicative dinoflagellates allowed a correlation of the succession wit...

The North Sea area constituted during the Cenozoic an epicontinental sea surrounded by landmasses delivering sediments for the basin. At the Eocene-Oligocene transition a dramatic change in source and type of sediments took place in the eastern North Sea. At this time the mainly hemipelagic clays of the Eocene were replaced by muddy to locally sand...