Papers by Stein-Erik Lauritzen
Architecture of a paleokarst breccia-pipe filed, Carboniferous, Svalbards
ABSTRACT Upwards-propagating collapse pipes typically form sinkholes where they meet the land sur... more ABSTRACT Upwards-propagating collapse pipes typically form sinkholes where they meet the land surface. Renewed dissolution of breccia in ancient pipes can have a similar effect. For these cases, probability-based models of sinkhole hazard are closely related to the expected mature architecture of the collapse-pipe field. We present a case study of the architecture of a square-kilometre field of collapse-pipes from the Carboniferous-Permian in which the pipes are documented in outcrop and using shallow geophysical methods. The study site is located on the Wordiekammen plateau in the Carboniferous Billefjorden half-graben basin on Spitsbergen. Cliffs bounding the plateau expose breccia pipes cutting a gently-dipping 200-m-thick series of platform carbonates, in turn underlain by stratiform breccias and residual pods of gypsum. Many of the breccia pipes are tall (>250 m) and postdate several shallow karstification episodes. Most pipes are inferred not to have reached the surface based on a lack of terrigenous material and fluvial structure, although several pipes show indications of such surface communication. Although the pipes are generally attributed to gypsum dissolution, a deep carbonate karstification event is inferred based on high temperature calcite cement, and burial dehydration of gypsum, may also have contributed to void formation. On the plateau top the collapse pipes are obscured by thick scree, thus km-scale size and spacing data for the pipes and faults was collected by mapping the bedrock with 2D ground-penetrating radar (GPR). GPR profiles were acquired on a grid with 25-meter line spacing, using 50 MHz antennas and achieving 30-40 m penetration. Breccia bodies were identified by steep-sided zones of complex diffraction patterns interrupting bedding-related continuous reflections. Two pipes were further studied in 3D using high-resolution GPR, tomographic seismic and geo-electric. These geophysical data were merged into a comprehensive 3D framework including helicopter-borne lidar and photo scans of the plateau rim geology, thus allowing an integrated visualization and interpretation of the different datasets. The GPR data show the breccia pipes to be slightly oblate with diameters ranging from 20 to over 100 m; 60 meters is a typical value. Approximately 10 pipes are identified in cliff-side outcrops bordering the GPR area, whereas 30 more are identified within the plateau by the GPR data. The GPR volume lies about 200 m above the pipe base, hence the pipe-length frequency-distribution data are incomplete. The strata are cut by small-offset (<5m) faults related to collapse processes and larger-offset faults related to regional basin extension. The breccia pipe field appears to be delimited by these more regional faults, in turn inferred to control the thickness of syn-rift gypsum and/or the hydrology of its dissolution. Collapse breccia pipes form strong vertical heterogeneities in rock properties such as porosity and perme- ability, matrix density, cement, mechanical strength and lithology, affecting fluid-flow characteristics on a meter to hundred-meter scale. It is rare that pipe fields are well exposed at the kilometre scale. Although some scaling data can be obtained from 3D oil-industry seismic reflection data but the resolution insufficient to visualize critical details. The outcrop combination of seismic, electric and geologic techniques facilitates the interpretation of 3D facies architectures and by proxy porosity-permeability relationships. Studies at the km scale are fundamental for understanding basic karst and collapse processes, and yield petrophysical models that can be applied predictively to natural hazards and groundwater or hydrocarbon exploitation in paleokarst settings.
The first occurrence of allophane as a speleothem-forming cave mineral in Norway is reported. It ... more The first occurrence of allophane as a speleothem-forming cave mineral in Norway is reported. It occurs in a fissure cave developed in granitic gneiss and appears to be formed by CO2 degassing (or microbiological action) from acidic seepage water originating from humic ponds and small bogs on the surface above the cave.
Speleological Institute (Emil Racovita), Clinicilor 5, Cluj, ROMANIA LFG-2, a 39.5 cm tall stalag... more Speleological Institute (Emil Racovita), Clinicilor 5, Cluj, ROMANIA LFG-2, a 39.5 cm tall stalagmite from northwestern Romania, has been dated by U-series α-spectrometric dating, and analyzed for stable isotope variations (δ 18 O, δ 13 C) along its growth axis. The sample grew all the way through oxygen isotope stage 5(a-e), and perhaps for some time into stage 4. In spite of a rather low uranium content and therefore imprecise chronology, the sample provides an interesting stable isotope record with high temporal resolution that correlates favorably with other speleothems and with the deep-sea record. Termination II is well defined in the record as a rapid shift from light (cold) to heavier (warm) δ 18 O values, when C3 vegetation seemed to dominate. The δ 13 C in a slow growth zone, corresponding to oxygen isotope stage 5d, as well after the stage 5/4 transition, suggests that C4 plants possibly dominated the surface environment. The δ 18 O record also correlate quite well with the α-dated FM-2 record from northern Norway.
There are general problems of distinguishing betwren tension and shear planes on the collective a... more There are general problems of distinguishing betwren tension and shear planes on the collective and individual level. In many cases, real distributions of tension and shear fractures cannot be distinguished. In these cases. general assumptions that either of the two types of fracture exclusively controls caves on the collective level become meaningless. Shear fractures are most often recognized individually as guiding fractures. and cave passage trends often correlate well with them. Beta analysis (intersection) of bedding planes and fractures seems like a promising directional approach for the analysis of structural control in caves. a)
Acta Chemica Scandinavica, 1981
Quaternary Science Reviews, 1996
Comparison of marine, lacustrine, and terrestrial records from twenty-four sites sug-QSR gests th... more Comparison of marine, lacustrine, and terrestrial records from twenty-four sites sug-QSR gests the existence of a 'Younger Dryas'-type climate oscillation just prior to the Oxygen Isotope Stage 6/5e boundary. These records include results from biostratigraphic, pedostratigraphic, and speleothem studies, as well as analyses of stable isotope compositions of marine records and ice cores. The climate oscillation is named after the warm Zeifen Interstadial and the cold Kattegat Stadial. The Zeifen Interstadial may be related to a major meltwater pulse in the Baffin Bay-Labrador Sea-Norwegian Sea region. The climate oscillation is presumably in part a result of a variation in ocean circulation, especially in the strength of the North Atlantic Drift, but changes in the atmospheric circulation also played an important role. The geographically widespread distribution of the oscillation suggests that the two-step deglaciation influenced both the northern and southern hemispheres.
Relict phreatic caves, in hanging positions within a glacial topography, pose an enigma with resp... more Relict phreatic caves, in hanging positions within a glacial topography, pose an enigma with respect to the speleogenetic interpretation. A glacier ice mass may provide liquid water and create caves anywhere in the adjacent rock, making glacier ice-contact as well as interglacial, meteoric speleogenesis feasible. The problem is reviewed with relevant glacier rheology, hydrology, and chemistry. The glacial environment was certainly able to overprint and widen already existing caves (sensu lato speleogenesis), while the full evolution of caves from tight fractures (sensu stricto speleogenesis) was slow and inefficient (about 1/40) as compared to nonglacial conditions. Off-print available upon request
El Soplao cave (Cantabria, northern Spain) was discovered in the mid-nineteenth century as result... more El Soplao cave (Cantabria, northern Spain) was discovered in the mid-nineteenth century as result of mining activity in La Florida mine. Spectacular helictites, anthodites and huge vadose speleothems are the most relevant aesthetic features of this show mine-cave. In some of its karst conduits there are also several evidences of palaeoflood that has intruded fine-grained detrital materials into the cave. Flowstones composed by aragonite laminas interlayered within successive thin strata of cemented silt and clay show clear evidences of these different events. The oldest sedimentary body is currently hung up about 30 cm above the cave floor. Discontinue aragonite layers formed under quiet vadose conditions by laminar flow on the detrital materials are alternated with alluvial deposits looped with a decrease of clastic material upwards and marked by sharp erosional surfaces. Close to the top of the flowstones, Fe-Mn oxide precipitation also occurred. Results from U-Th dating of the lo...
International Journal of Speleology, 2006
Isotope Stage 11, The ‘Super-Interglacial’, From A North Norwegian Speleothem
Studies of Cave Sediments, 2007
... Presumably the visible charcoal fragments (10-50 uM) were carried into the cave with theminor... more ... Presumably the visible charcoal fragments (10-50 uM) were carried into the cave with theminor flood event but Page 274. Z70 SE LAURITZEN & J. LUNDBERG it is impossible to know if the pollen and carbonized dust were carried in on air currents. ...
AMS radiocarbon dating of glacigenic sediments with low organic carbon content-an important tool for reconstructing the history of glacial variations in Norway
ABSTRACT In this paper we present and examine a comprehensive series of dates (> 200), whi... more ABSTRACT In this paper we present and examine a comprehensive series of dates (> 200), which underpins a new reconstruction of ice-sheet fluctuations along nine transects extending from inland to the coast in Norway. Sediments with low organic content dominate the dated materials, particularly from the inland sites, some of which may have a marine origin. Consequently, the new dates reported here, include mainly 14C-dates of bulk organic sediment samples. The geochronology of sites located in coastal areas is mainly based on shell dates. A considerable number (> 100) of previously published dates are also employed, both as 'control dates' for the new synthesis, and as components of the overall geochronological data base. The data base also includes 14C-dates of bones and calcareous concretions, U/Th-dates of speleothems and calcareous concretions, and TL/OSL-dates of wind-blown and water-lain sand. Brief reference is also made to relative age estimates based on amino acid analyses and correlation using magnetostratigraphy. The accuracy and precision of the chronology is examined on a millennium scale. The dates give ranges of ages which provide a coherent chronology of the stratigraphic succession and of the main events, which span the Middle to Late Weichselian interval.
Quaternary Science Reviews, 2011
This review provides an up-to-date synthesis of the matrilineal phylogeography of a uniquely well... more This review provides an up-to-date synthesis of the matrilineal phylogeography of a uniquely wellstudied Holarctic mammal, the brown bear. We extend current knowledge by presenting a DNA sequence derived from one of the earliest known fossils of a polar bear (dated to 115 000 years before present), a species that shares a paraphyletic mitochondrial association with brown bears. A molecular clock analysis of 140 mitochondrial DNA sequences, including our new polar bear sequence, provides novel insights into the times of origin for different brown bear clades. We propose a number of regional biogeographic scenarios based on genetic data, divergence time estimates and paleontological records. The case of the brown bear provides an example for researchers working with less well-studied taxa: it shows clearly that phylogeographic models based on patterns of modern genetic variation alone can be substantially improved by including data on historical patterns of genetic diversity in the form of ancient DNA sequences derived from accurately dated samples and by using an approach to divergence-time estimation that suits the data under analysis. Using such approaches it has been possible to (i) establish that the processes shaping modern genetic diversity in brown bears acted recently, within the last three glacial cycles; (ii) distinguish among hypotheses concerning species' responses to climatic oscillations in accordance with the lack of phylogeographic structure that existed in brown bears prior to the last glacial maximum (LGM); (iii) reassess theories linking monophyletic brown bear populations to particular LGM refuge areas; and (iv) identify vicariance events and track analogous patterns of migration by brown bears out of Eurasia to North America and Japan.
Kadar je obseg alogenega dotoka velik v primerjavi s povr{ino kra{kega izdanka govorimo o "pasast... more Kadar je obseg alogenega dotoka velik v primerjavi s povr{ino kra{kega izdanka govorimo o "pasastem krasu" (=stripe karst). V metamorfnih marmorjih Skandinavskih Kaledonidov je to najpogostej{i tip krasa. Izraz "Norve{ki tip krasa", kot se za tak kras uporablja v terminologiji, je uvedel norve{ki geolog Gunnar Horn. O pasastem krasu govorimo, ko je razmerje med dol`ino in {irino (γ) kra{kega izdanka ve~je od 3, o popolno razvitem pasastem krasu pa v primeru, ko to razmerje dose`e vrednost 30. Pasovi marmorja so vertikalni ali nagnjeni pod razli~nim vpadnim kotom, vodonosnik v marmorju je lahko zaprt ali vise~. Klju~ne besede: kontaktni kras, pasasti kras, Norve{ka, Kaledonidi, speleogeneza.
International Journal of Speleology, Jan 1, 2010
The analytical problems of dating gypsum speleothems with the U-series technique are reviewed. Gy... more The analytical problems of dating gypsum speleothems with the U-series technique are reviewed. Gypsum speleothems are, in general, very low in U content, challenging the limits of detection methods. Various approaches to dissolving gypsum and isolation of actinides from the matrix include ion-pairing dissolution with magnesium salts and using nitric acid. The most precise dating technique is Thermal Ionization Mass Spectrometry (TIMS), combined with Fe(OH) 3 scavenging and anionic exchange chromatography. Less satisfactory, but much quicker, is direct retention of actinides from HNO 3 by means of TRU resin and MC-ICP-MS detection. We have tested these methods on gypsum speleothems from the Sorbas karst in Spain and from the Naica caves in Mexico.
Quaternary Geochronology, 2009
Luminescent lamination in a stalagmite from northern Norway is used to construct a w2780-year lon... more Luminescent lamination in a stalagmite from northern Norway is used to construct a w2780-year long, floating record of annual growth rate. Thermal ionisation mass-spectrometric (TIMS) U-Th ages (n ¼ 12) were determined along the growth axis and three subsample locations and ages (corrected and uncorrected for initial 230 Th/ 232 Th activity) were selected as anchor points for the floating chronology. On the basis of these anchor points, termination of growth occurred between AD 1729 and AD 1826. The annual banding records are used to evaluate the initial 230 Th/ 232 Th activity ratio adopted for correction of the U-Th ages. To achieve a reasonable fit between U-Th ages and estimates predicted by the anchored annual band age models, mean initial 230 Th/ 232 Th activity ratios of between 0.44 and 1.47 must be invoked. However, there remains a reasonable degree of scatter about the expected linear relationship between annual bands and U-Th chronology for individual subsamples indicating that the use of a single correction factor for Holocene stalagmites should be applied with caution. Stalagmite growth rate fluctuates on annual to centennial scale. The growth termination of the stalagmite presented here could have been a result of environmental change associated with the Little Ice Age, or, possibly local percolation pathway changes after an M s w 6 earthquake in the region in AD 1819. Stable-isotope data from the same axis of growth show a pattern similar to the large-scale growth rate variations, and these combined proxy records are interpreted as showing gradual cooling and/or shortening of the vegetation growth season for the last 3000 years.
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Papers by Stein-Erik Lauritzen