Luminescence dating of ice‐marginal deposits in northern Germany: evidence for repeated glaciations during the Middle Pleistocene (MIS 12 to MIS 6)          下载免费PDF全文

Julia Roskosch  Jutta Winsemann  Ulrich Polom  Christian Brandes  Sumiko Tsukamoto  Axel Weitkamp  Werner A. Bartholomäus  Dierk Henningsen  Manfred Frechen 《Boreas: An International Journal of Quaternary Research》2015,44(1):103-126

The exact number, extent and chronology of the Middle Pleistocene Elsterian and Saalian glaciations in northern Central Europe are still controversial. This study presents new luminescence data from Middle Pleistocene ice‐marginal deposits in northern Germany, giving evidence for repeated glaciations during the Middle Pleistocene (MIS 12 to MIS 6). The study area is located in the Leine valley south of the North German Lowlands. The data set includes digital elevation models, high‐resolution shear wave seismic profiles, outcrop and borehole data integrated into a 3D subsurface model to reconstruct the bedrock relief surface. For numerical age determination, we performed luminescence dating on 12 ice‐marginal and two fluvial samples. Luminescence ages of ice‐marginal deposits point to at least two ice advances during MIS 12 and MIS 10 with ages ranging from 461±34 to 421±25 ka and from 376±27 to 337±21 ka. The bedrock relief model and different generations of striations indicate that the older ice advance came from the north and the younger one from the northeast. During rapid ice‐margin retreat, subglacial overdeepenings were filled with glaciolacustrine deposits, partly rich in re‐worked Tertiary lignite and amber. During MIS 8 and MIS 6, the study area may have been affected by two ice advances. Luminescence ages of glaciolacustrine delta deposits point to a deposition during MIS 8 or early MIS 6, and late MIS 6 (250±20 to 161±10 ka). The maximum extent of both the Elsterian (MIS 12 and MIS 10) and Saalian glaciations (MIS 8? and MIS 6) approximately reached the same position in the Leine valley and was probably controlled by the formation of deep proglacial lakes in front of the ice sheets, preventing a further southward advance.  相似文献   

Locomotor activity rhythm in the Japanese eel Anguilla japonica elvers     

DOU Shuozeng  TSUKAMOTO Katsumi 《海洋学报(英文版)》2007,26(5):76-89

Under artificial LD cycles(6,12,18 L),the elvers of Japanese eel,Anguilla japonica,showed a 24 h cycle of locomotor activity rhythm being most active at light transitions:the eels' activity rose to a primary peak after lights-off,followed by a quiescent period during which they buried into the shelters or lying motionlessly on sand for most of the time,and then reached a secondary peak before lights-on.Elvers could resynchronize their activity rhythm with a new photo cycle within 4 d.Moreover,their activity level at dark phase significantly increased as the light period was prolonged:higher activity levels during shorter dark period.However,the elvers did not display clearly the existence of a circadian rhythm under constant light or dark conditions.The timing of daily activity rhythm evidenced in the Japanese eels may occur through the action of the LD cycles with a weak participation of an endogenous circadian system.In all the LD cycles,over 99% of the activity occurred in the dark phase,indicating that the eels were always nocturnally active no matter what time of day it might be.Under 12 L conditions,the eels' activity level and the time outside sand were significantly elevated both at light and dark phases as temperature increased from 10~15 to 20~25 ℃.The activity rhythm pattern(i.e.,two peaks occurring around light transitions) did not apparently change among temperatures.However,in contrast with the primary activity peaks immediately after lights-off at 20 and 25 ℃,the timing of the primary peaks at 10 and 15 ℃ showed a latency of a few hours following lights-off,indicating the inhibiting effect of low temperature on the eels' activity.  相似文献   

Model simulations of carbon sequestration in the northwest Pacific by patch fertilization     

Katsumi Matsumoto 《Journal of Oceanography》2006,62(6):887-902

Iron fertilization of nutrient-rich surface waters of the ocean is one possible way to help slow the rising levels of atmospheric CO₂ by sequestering it in the oceans via biological carbon export. Here, I use an ocean general circulation model to simulate a patch of nutrient depletion in the subpolar northwest Pacific under various scenarios. Model results confirm that surface fertilization is an inefficient way to sequester carbon from the atmosphere (Gnanadesikan et al., 2003), since only about 20% of the exported carbon comes initially from the atmosphere. Fertilization reduces future production and thus CO₂ uptake by utilizing nutrients that would otherwise be available later. Effectively, this can be considered as leakage when compared to a control run. This “effective” leakage and the actual leakage of sequestered CO₂ cause a significant, rapid decrease in carbon retention (only 30–45% retained after 10 years and less than 20% after 50 years). This contrasts markedly with the almost 100% retention efficiency for the same duration using the same model, when carbon is disposed directly into the northwest Pacific (Matsumoto and Mignone, 2005). As a consequence, the economic effectiveness of patch fertilization is poor in two limiting cases of the future price path of carbon. Sequestered carbon in patch fertilization is lost to the atmosphere at increasingly remote places as time passes, which would make monitoring exceedingly difficult. If all organic carbon from one-time fertilization reached the ocean bottom and remineralized there, acidification would be about −0.05 pH unit with O₂ depletion about −20 μmol kg⁻¹. These anomalies are probably too small to seriously threaten deep sea biota, but they are underestimated in the model because of its large grid size. The results from this study offer little to advocate purposeful surface fertilization as a serious means to address the anthropogenic carbon problem.  相似文献   

Tidal energy balance in the Seto Inland Sea     

Tetsuo Yanagi  Hidetaka Takeoka  Hideshi Tsukamoto 《Journal of Oceanography》1982,38(5):293-299

The tidal volume transport in the Seto Inland Sea is calculated. The cross-section where the volume transport of the M₂ tide is zero, is located around the western part of Bisan Strait. The tidal energy dissipation of the M₂ tide by friction is 6.30×10¹⁶ ergs s^–1 in the Seto Inland Sea. The quality factorQ for the M₂ tide is 20.2. The total energy dissipation of the M₂, S₂, K₁ and O₁ tides is 7.99×10¹⁶ ergs s^–1.  相似文献   

泰国北部Inthanon带外来硅质岩块的中、晚二叠世放射虫：对与古特提斯消减有关的混杂岩形成时代的约束     

Yoshihito KAMATA  Hidetoshi HARA  Katsumi UENO  Apsorn SARDSUD  Thasinee CHAROENTITIRAT  Punya CHARUSIRI  Ken-ichiro HISADA 《地球学报》2012,33(S1):36-37

The Inthanon Zone of Northern Thailand, origi-nally proposed by Barr and Macdonald (1991), is characterized by the occurrence of Paleo-Tethyan pe-lagic sediments including Carboniferous–Permian seamount-type carbonate associated with oceanic ba-saltic rocks and Middle Devonian–Middle Triassic radiolarian chert (Ueno, 1999; Ueno and Hisada, 2001; Ueno and Charoentitirat, 2011). These pelagic rocks have been mainly studied from the viewpoint of bio-stratigraphy to clarify the duration of their deposition. These studies concluded the Paleo-Tethys to be a vast ocean basin once existed between the Indochina and Sibumasu continental blocks during Devo-nian–Triassic times.  相似文献   

泰国北部三叠系Lampang群Doi Long组的有孔虫组合与沉积环境     

Akira MIYAHIGASHI  Katsumi UENO  Thasinee CHAROENTITIRAT  Yoshihito KAMATA 《地球学报》2012,33(S1):45-49

A rich foraminiferal assemblage, consisting of abundant Aulotortus sinuosus and A. tumidus in association with Lamelliconus multispirus, Endoteba ex gr. controversa, E. ex gr. badouxi, Endotebanella kocaeliensis, Endotriada tyrrhenica, Endotriadella wirzi, Malayspirina fontainei, Ammobaculites rhaeticus, Diplotremina astrofimbriata, Agathammina austroalpina, and others, was found in the Doi Long Formation of the Triassic Lampang Group, Northern Thailand. These foraminifers suggest that the formation is referable to the Carnian (early Late Triassic), which is consistent with the age estimated by ammonoids. In microfacies, peloidal grainstone, bioclastic grainstone, sponge-microbial boundstone, and oolitic grainstone were recognized in the Doi Long Formation. Based on microfacies, three depositional facies, the lagoon facies, reef facies, and shoal facies, are recognized in this formation. These lines of evidence are suggestive that the Doi Long Formation was deposited in a reef or bank setting rather than a ramp setting.  相似文献   

Palaeomagnetism of stalagmites (speleothems) in SW Japan     

Hayao Morinaga  Hiroo Inokuchi  Katsumi Yaskawa 《Geophysical Journal International》1989,96(3):519-528

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OSL dating of glacial deposits during the Last Glacial in the Terskey-Alatoo Range, Kyrgyz Republic     

C. Narama  R. Kondo  S. Tsukamoto  T. Kajiura  C. Ormukov  K. Abdrakhmatov 《Quaternary Geochronology》2007,2(1-4):249-254

Optically stimulated luminescence (OSL) dating was applied to glacial and loess deposits in the north flank of the Terskey-Alatoo Range, Kyrgyz Republic, to elucidate the glacier chronology of the central Asian mountains during the Last Glacial. Moraines in five parts of study area were classified into four stages (Terskey Stages I–IV) based on their geographical position and elevation, and their moraine rock weathering. According to this classification, the oldest moraines (Terskey Stage I) were at 2100–2250 m a.s.l. and the second-oldest moraines (Terskey Stage II) were at 2400–2700 m a.s.l. Quartz samples from moraines of these two stages were used for OSL dating. The OSL ages of the quartz samples indicate that glacier expansion in the Terskey Stage II occurred between 21 and 29 ka BP.  相似文献   

Importance of geochemical transformations in determining submarine groundwater discharge-derived trace metal and nutrient fluxes     

Aaron J. Beck  Yoko Tsukamoto  Antonio Tovar-Sanchez  Miguel Huerta-Diaz  Henry J. Bokuniewicz  Sergio A. Sañudo-Wilhelmy 《Applied Geochemistry》2007

Seasonal (Spring and Summer 2002) concentrations of dissolved (<0.22 μm) trace metals (Ag, Al, Co, Cu, Mn, Ni, Pb), inorganic nutrients (NO₃, PO₄, Si), and DOC were determined in groundwater samples from 5 wells aligned along a 30 m shore-normal transect in West Neck Bay, Long Island, NY. Results show that significant, systematic changes in groundwater trace metal and nutrient composition occur along the flowpath from land to sea. While conservative mixing between West Neck Bay water and the groundwaters explains the behavior of Si and DOC, non-conservative inputs for Co and Ni were observed (concentration increases of 10- and 2-fold, respectively) and removal of PO₄ and NO₃ (decreases to about half) along the transport pathway. Groundwater-associated chemical fluxes from the aquifer to the embayment calculated for constituents not exhibiting conservative behavior can vary by orders of magnitude depending on sampling location and season (e.g. Co, 3.4 × 10²– 8.2 × 10³ μmol d⁻¹). Using measured values from different wells as being representative of the true groundwater endmember chemical composition also results in calculation of very different fluxes (e.g., Cu, 6.3 × 10³ μmol d⁻¹ (inland, freshwater well) vs. 2.1 × 10⁵ μmol d⁻¹(seaward well, S = 17 ppt)). This study suggests that seasonal variability and chemical changes occurring within the subterranean estuary must be taken into account when determining the groundwater flux of dissolved trace metals and nutrients to the coastal ocean.  相似文献   

Measuring the k–S–p relations on DNAPLs migration     

Masashi Kamon  Kazuto Endo  Takeshi Katsumi 《Engineering Geology》2003,70(3-4):351-363

Migration characteristics of dense non-aqueous phase liquids (DNAPLs) in the subsurface can be expressed as a water–DNAPL two-phase system based on mainly the k–S–p relations, which describe the relations among relative permeability (k), degree of water saturation (S), and capillary pressure head (p). The aims of this research are to develop an experimental system with new type of probes, such as the electrical conductivity probe for measuring the degree of water saturation and the hydrophilic and hydrophobic tensiometer for measuring the pore water and DNAPL pressures, and also to estimate the results obtained from the developed experimental system. From these tests, the excellent k–S–p relations were obtained and the efficiency and validity of this developed experimental system have been confirmed in terms of the concept of the scaling coefficient calculated by interfacial tensions.  相似文献