Na 1 Nachlass Max Horkheimer, 103 - Korrespondenzen u.a. mit Maria Pattermann und Franz Neumann (p. III 11, 1-335)

1 Drucksache der Rechtsanwaltskanzlei Pacht, Tannenbaum & Ross, 1951; 2 Briefe zwischen der Pädagogischen Hauptstelle der Gewerkschaft Erziehung u. Wissenschaft und Max Horkheimer, 1954; 1 Brief vom Pädagogischen Verlag B. Schulz an Max Horkheimer, 1950; 3 Briefe zwischen dem Professor Erwin Walter Palm und Max Horkheimer, 1957-1958; 2 Briefe zwischen Helena Brans und Max Horkheimer, 1953; 2 Briefe vom Park-Hotel Frankfurt an Max Horkheimer,1957-1958; 1 Brief von Enno Patalas an Max Horkheimer, 1 Brief von Theodor W. Adorno an Enno Patalas, 1956; 2 Briefe zwischen Dieter Pätzold und Max Horkheimer, 1952; 8 Briefe zwischen Maria Pattermann und Max Horkheimer, 1952-1958; 2 Briefe zwischen F. Perrot und Max Horkheimer, 1953; 2 Briefe zwischen der Buchhandlung Werner Peter und Max Horkheimer, 1954; 3 Briefe zwischen Alfred Peters und Max Horkheimer, 1952-1953; 1 Zeugnis von dem Studenten Joachim Peter, 1953; 1 Brief von Max Horkheimer an F.H. Peterson, 1950; Briefwechsel zwischen dem Studenten Klaus Peuker und Max Horkheimer, 1951; 1 Brief des Chefredakteuren Karl Pfannkuch an Max Horkheimer, 1955; 1 Brief von Dr. Karl Pfauter an Max Horkheimer, 1952; Briefwechsel zwischen der Studentin Renate Pflaume und Max Horkheimer, 1952; Briefwechsel zwischen Joseph B. Phillips und Max Horkheimer, 1955; 1 Brief von Professor Josef Pieper an Max Horkheimer , 1951; 1 Brief von Ehrenfried Pihan an Max Horkheimer, 1953; 1 Brief von F. G. Pincus an Theodor W. Adorno, 1954; Briefwechsel zwischen dem Professor Koppel S. Pinson und Max Horkheimer, 1956; 2 Briefe zwischen dem Professor Kurt Pinthus und Max Horkheimer, 1953; 1 Brief an Dr. Knut Pipping von Max Horkheimer, 1950; 2 Briefe zwischen Erwin Piscator und Max Horkheimer, 1954; Briefwechsel zwischen der Max-Planck-Gesellschaft zur Förderung der Wissenschaften und Max Horkheimer, 1953-1955; Briefwechsel zwischen dem Professor Richard Plant und Max Horkheimer, 1953 und 2 Briefe zwischen Professor Richard Plant und Margarete Feretty-Füredi, 1953; Briefwechsel zwischen dem Professor Johann Plenge und Max Horkheimer, 1951-1952; Briefwechsel zwischen Barbara Pleyer und Max Horkheimer, 1954; 1 Brief von Erich Paul Pechmann an Max Horkheimer, 1952; Briefwechsel zwischen Dr. Gerhard Poetzsch und an Max Horkheimer, 1958; Briefwechsel zwischen dem Committee on Science & Freedom und Max Horkheimer, 1955-1956; 1 Brief an den Professor Rudolf Pohl von Max Horkheimer, 1953; 1 Brief von der Zeitschrift "Die politsche Meinung" an Max Horkheimer, 1956; 1 Brief von Max F. Pollack an Max Horkheimer, 1954; 1 Brief von dem Professor Wilhelm Polligkeit an Max Horkheimer, 1951; 1 Brief von dem Poli-Verlag an Max Horkheimer, 1950; Briefwechsel zwischen Alexej Poremsky und Max Horkheimer, 1955; 1 Brief von Rita Post an Max Horkheimer, 1952; 1 Brief von Max Potzin an Max Horkheimer, 1951; Briefwechsel zwischen dem Oberstudienrat Max Preitz und Max Horkheimer, 1955; 1 Brief von dem Professor Wolfgang Preiser an Max Horkheimer, 1952; 1 Gutachten und Beilagen von Dr. Karl A. Preuschen an Max Horkheimer, 1955; Briefwechsel und Beilagen zwischen dem Direktor des The Commonwealth Fund E. K. Wickman und Max Horkheimer, 1955; Briefwechsel zwischen Klaus H. Pringsheim und Max Horkheimer, 1952-1958; 1 Brief von Curt Freiherr von Preuschen an Max Horkheimer, 1953; Briefwechsel zwischen Rüdiger Proske und Max Horkheimer, 1951; Briefwechsel und Beilagen zwischen Dr. Harry Pross und Max Horkheimer, 1954; 1 Brief von dem Professor Franz Neumann an Max Horkheimer, 1954; 1 Brief an G. H. Graber von Max Horkheimer, 1953; Briefwechsel zwischen dem Quaker Service und Max Horkheimer, 1950; Briefwechsel zwischn Günther Quandt und Max Horkheimer, 1953 und 2 Todesanzeigen, 1955; 1 Brief an den Querido-Verlag von Max Horkheimer, 1951; Briefwechsel zwischen Emil Querinjean und Max Horkheimer, 1955; Briefwechsel zwischen John Raatjes und Max Horkheimer, 1956; Briefwechsel zwischen der Zeitschrift the humanist radical und Max Horkheimer, 1957; Briefwechsel zwischen Sitangghu Chatterji und Max Horkheimer, 1957; 1 Brief von der Radio Corporation of America an Max Horkheimer, 1953; 1 Brief und Beilagen vom Radiodiffusion et Télévision Francaises an Max Horkheimer, 1955; Briefwechsel zwischen dem Österreichischer Rundfunk Radio Wien und Max Horkheimer, 1956; 1 Brief von dem Professor Boris Rajewsky an Max Horkheimer, 1953; 1 Brief an Else Rang von Max Horkheimer, 1950; Briefwechsel zwischen Heinz Raspini und Max Horkheimer, 1956; 1 Drucksache zwischen Hanna Becker vom Rath und Max Horkheimer, 1953; 1 Telegramm von dem Professor Roland Rather an Max Horkheimer und 2 Briefe von Max Horkheimer an Roland Rather, 1957; Briefwechsel zwischen dem Professor L. J. Rather und Max Horkheimer, 1955; Briefwechsel zwischen Phillip Roth und Max Horkheimer, 1958; Briefwechsel zwischen Sibnarayan Ray und Max Horkheimer, 1956-1957; Briefwechsel mit Beilagen zwischen dem Rationalisierungs-Kuratorium der Deutschen Wirtschaft und Max Horkheimer, 1954; 1 Aktennotiz von dem Jornalisten Rasten der dänischen Zeitung Politiken, 1953; Briefwechsel zwischen Wolfgang M. Rauch und Max Horkheimer, 1956; 1 Anzeige der Ingeborg Rauter, 1953; 1 Brief von dem Hotel Reber au lac an Max Horkheimer, 1955; Briefwechsel zwischen Alice Reboly und Max Horkheimer, 1955; 3 Briefe an die Regensburger Zeitungen von Max Horkheimer, 1956; 1 Brief an den Professor Klaus Reich von Max Horkheimer, 1950; Briefwechsel zwischen dem Reinhardt, Ernst, Verlag und Max Horkheimer, 1953; 1 Brief von dem Apotheker Hermann Reitberger an Max Horkheimer, 1955; Briefwechsel zwischen Dr. Paul Reiwald und Max Horkheimer, 1950; 1 Brief von dem Journalist Godo Remszhardt an Max Horkheimer, 1954; Briefwechsel zwischen Dr. Irmgard Rexroth-Kern und Max Horkheimer, 1952; Briefwechsel zwischen Hans Rheinbay und Max Horkheimer, 1955; 1 Brief von der Universität Bonn an Max Horkheimer, 1953; 1 Brief an den Rheinischer Merkur von Max Horkheimer, 1951; 1 Brief an die Rheinische Post von Max Horkheimer, 1954; 1 Brief an Hans Richter von Max Horkheimer, 1954; Briefwechsel zwischen Dr. Hermann Riefstahl und Max Horkheimer, 1957; Briefwechsel zwischen dem Professor Svend Riemer und Max Horkheimer, 1957; Briefwechsel zwischen dem Ring-Verlag und Max Horkheimer, 1957; Briefwechsel zwischen Werner Rings und Max Horkheimer, 1954; Briefwechsel zwischen Martha Ritter-Raabe und Max Horkheimer, 1955; Briefwechsel zwischen Otto-Heinz Rocholl und Max Horkheimer, 1954; 1 Brief von Hilde Rodemann an Max Horkheimer, 1952; 1 Brief von Edouard Roditi an Max Horkheimer, 1951 und 1 Brief von Theodor W. Adorno an Edouard Roditi, 1951; Briefwechsel zwischen der Zeitschrift Studenten-Kurier und Max Horkheimer, 1955; 1 Brief von Karl Roeloffs an Max Horkheimer, 1953; Briefwechsel zwischen der Kunsthistorikerin Hanna Rhode und Max Horkheimer, 1950-1951; 1 Brief an Dr. Anna Ronge von Max Horkheimer, 1954; 2 Brief an Kathe Romney von Max Horkheimer, 1952-1955; Briefwechsel zwischen Dr. Paul Rompel und Max Horkheimer, 1952; 1 Brief an den Zahnartz Dr. Ingo Ropper von Max Horkheimer, 1953; Briefwechsel zwischen Ilse Wallis Ross und Max Horkheimer, 1955-1956; 1 Brief von dem Professor Hans W. Rosenhaupt an Max Horkheimer, 1952; 1 Brief von Rosenthal an Max Horkheimer, 1958; Briefwechsel zwischen dem Generalstaatsanwalt und Staatssekretär Erich Rosenthal-Pelldram und Max Horkheimer, 1952-1956; Briefwechsel zwischen Lessing J. Rosenwald und Max Horkheimer, 1950; Briefwechsel zwischen dem Lieutenant Dr. Alan O. Ross und Max Horkheimer, 1955; 4 Briefe und Beilagen von Günther Roth an Max Horkheimer, 1953-1957; Briefwechsel zwischen dem Professor Wolfram Eberhardt und Max Horkheimer, 1955; 1 Brief an den Professor M. A. Stewart von Theodor W. Adorno, 1955; Briefwechsel zwischen dem Professor Rheinhard Bendix und Max Horkheimer, 1955; Briefwechsel zwischen der Studentin Valentine Rothe und Max Horkheimer, 1957; 1 Brief von dem Student Rudolf Rothrock an Max Horkheimer, 1953; 1 Brief von Guy Roustang an Max Horkheimer, ohne Jahr; 1 Brief von Heinz Maria Ledig-Rowohlt an Max Horkheimer, 1950; Briefwechsel zwischen Ellen Roy und Max Horkheimer, 1956; Briefwechsel zwischen dem Professor Paul Royen und Max Horkheimer, 1954; Briefwechsel zwischen dem Staatsminister August Rucker und Max Horkheimer, 1955-1957 1 Brief an den Staatsminister August Rucker von Leopold von Wiese, 1955; 1 Bericht von Walter Rüegg, 1953 und 2 Briefe von Max Horkheimer an den Professor Walter Rüegg, 1955; 3 Briefe an den Professor Alexander Rüstow von Max Horkheimer, 1953-1958; Briefwechsel zwischen Käthe von Ruckteschell und Max Horkheimer, 1951-1954; Briefwechsel zwischen dem Student Gerhard Rudolph und Max Horkheimer, 1954; 1 Brief von der Ruf und Echo, Arbeitsgemeischaft an Max Horkheimer, 1952; 3 Briefe an den Professor Jay Rumney von Max Horkheimer, 1952-1954; Briefwechsel zwischen Clarence R. Rungee und Max Horkheimer, 1951-1952;

Na 1 Nachlass Max Horkheimer, 532 - Korrespondenzen u.a. mit Otto Kirchheimer und Leo Löwenthal (p. VI 11, 287 - 514)

55 Briefe zwischen Otto Kirchheimer, Anne Kirchheimer und Max Horkheimer, 1937 - 1947; 1 Brief von Otto und Anne Kirchheimer an Frederick Pollock, 06.08.1939; 2 Briefe zwischen der Rockfeller Foundation (New York) und Max Horkheimer, März 1941; 1 Brief von dem Oberlaender Trust an Frederick Pollock, 10.02.1941; 1 Brief von Otto Kirchheimer an Frederick Pollock, 06.08.1939; 1 Brief von Max Horkheimer an das American College Bureau (Chicago), 07.10.1940; 1 Brief von Max Horkheimer an das College and Specialist Bureau (Memphis, T.), 23.09.1939; 2 Briefe zwischen Max Horkheimer und dem Social Science Research Council (New York), 17.12.1938; 73 Briefe zwischen Leo Löwenthal und Max Horkheimer 1933 - 1935; 1 Brief von dem Europa Verlag A. G. (Zürich) an Max Horkheimer, 30.11.1935; 1 Brief von Max Horkheimer an das United States Department of Labor (New York), 03.05.1935; 2 Briefe von Hugo Sinzheimer an Max Horkheimer, 11.06.1934; 1 Brief von Leo Löwenthal an Hugo Sinzheimer, 16.07.1934; 2 Briefe zwischen Leo Löwenthal und Fritz Schiff, 1934/1935;

Na 1 Nachlass Max Horkheimer, 563 - Korrespondenzen u.a. mit Alice H. Maier und Leo Löwenthal (p. VI 27, 1-253)

Briefwechsel zwischen Max Horkheimer und Alice H. Maier; 5 Briefe an Maurice und Carolyn Tumarkin von Max Horkheimer, 1957/1964; 1 Brief von Max Horkheimer an Charles Gorman, 27.04.1957; 1 Brief von Alice H. Maier an die Marquis Company (Chicago), 06.05.1957; 2 Briefe an H. P. Edelman von Max Horkheimer, 1964; 3 Briefe zwischen Alice H. Maier und H. P. Edelman, 1957/1963; 1 Brief von Margot von Mendelssohn an Alice H. Maier, 01.04.1957; 1 Brief an Richard Corwine Stevenson von Max Horkheimer, 16.03.1957; 1 Brief von Max Horkheimer an Inge Aicher-Scholl, 26.02.1957; 1 Brief an Herman Strasburger von Max Horkheimer, 21.01.1957; 1 Brief von Elisabeth Richter an Alice H. Maier, [1957]; 1 Brief an den Director of International Operations (Washington) von Chauncy D. Harris, 05.02.1957; 1 Brief von Alice H. Maier an Comptroller of Customs (New York), 11.01.1957; 1 Brief an Herbert Marcuse von Alice H. Maier, 14.01.1957; 2 Briefe zwischen Alice H. Maier und The Saturday Evening Post (Philadelphia), Oktober 1956; 1 Brief an die Staats-Herold Corporation (Woodside) von Alice H. Maier, 24.09.1956; 2 Briefe zwischen Alice H. Maier und Werner Thönnessen, 1956; 2 Briefe zwischen dem National Better Business Bureau (New York) und Alice H. Maier, 1956; 2 Briefe zwischen Alice H. Maier und Herman L. Filene, Januar 1956; 5 Briefe zwischen Max Horkheimer und Edwin J. Lukas, 1962 - 1963; 7 Briefe zwischen Monroe Karasik und Max Horkheimer, 1963; 1 Brief von Max Horkheimer an James Conant, 30.05.1963; 1 Brief an John J. McCloy von Max Horkheimer, 30.05.1963; 3 Briefe an Herman S. Klein von Alice H. Maier, 1960/1963; 1 Brief von Max Horkheimer an Hartley Chemists (New York), 06.02.1962; 1 Brief an Columbia Chemists (New York) von Max Horkheimer, 06.02.1962; 1 Brief von Max Horkheimer an A. P. Bersohn, 06.06.1962; 1 Brief an A. P. Bersohn von Alice H. Maier, 20.04.1962; 1 Brief an Alice H. Maier von Paul Kind, 22.05.1962; 1 Brief an Cyrus C. Hoffman von Alice H. Maier, 23.03.1961; 2 Briefe von Alice H. Maier an Friedrich Pollock, 1960/1966;

(Table 1) U and Th isotope analyses of pyrite and anhydrite of ODP Site 158-957

Hydrothermal circulation at oceanic spreading ridges causes sea water to penetrate to depths of 2 to 3 km in the oceanic crust where it is heated to ~400 °C before venting at spectacular 'black smokers'. These hydrothermal systems exert a strong influence on ocean chemistry (Edmond et al., 1979, doi:10.1016/0012-821X(79)90061-X), yet their structure, longevity and magnitude remain largely unresolved (Elderfield and Schultz., 1996, doi:10.1146/annurev.earth.24.1.191). The active Transatlantic Geotraverse (TAG) deposit, at 26° N on the Mid-Atlantic Ridge, is one of the largest, oldest and most intensively studied of the massive sulphide mounds that accumulate beneath black-smoker fields. Here we report ages of sulphides and anhydrites from the recently drilled (Humphris et al., 1995, doi:10.1038/377713a0) TAG substrate structures -determined from 234U-230Th systematics analysed by thermal ionization mass spectrometry. The new precise ages combined with existing data (Lalou et al., 1993, doi:10.1029/92JB01898; 1998, doi:10.2973/odp.proc.sr.158.214.1998) show that the oldest material (11,000 to 37,000 years old) forms a layer across the centre of the deposit with younger material (2,300-7,800 years old) both above and below. This stratigraphy confirms that much of the sulphide and anhydrite are precipitated within the mound by mixing of entrained sea water with hydrothermal fluid (James and Elderfield, 1996, doi:10.1130/0091-7613(1996)024<1147:COOFFA>2.3.CO;2). The age distribution is consistent with episodic activity of the hydrothermal system recurring at intervals of up to 2,000 years.

High-resolution multi-proxy record of the last glacial period from Lake Van, eastern Anatolian high plateau, Turkey

Detailed analyses of the Lake Van pollen, Ca/K ratio and stable oxygen isotope record allow the identification of millennial-scale vegetation and environmental changes in eastern Anatolia throughout the last glacial (~75-15 ka BP). The climate within the last glacial was cold and dry, with low arboreal pollen (AP) levels. The driest and coldest period corresponds to Marine Isotope Stage (MIS) 2 (~28-14.5 ka BP) dominated by the highest values of xerophytic steppe vegetation. Our high-resolution multi proxy record shows rapid expansions and contractions of tree populations that reflects variability in temperature and moisture availability. This rapid vegetation and environmental changes can be linked to the stadial-interstadial pattern of the Dansgaard-Oeschger (DO) events as recorded in the Greenland ice cores. Periods of reduced moisture availability were characterized by enhanced xerophytic species and high terrigenous input from the Lake Van catchment area. Furthermore, comparison with the marine realm reveals that the complex atmosphere-ocean interaction can be explained by the strength and position of the westerlies, which is responsible for the supply of humidity in eastern Anatolia. Influenced by diverse topography of the Lake Van catchment, larger DO interstadials (e.g. DO 19, 17-16, 14, 12 and 8) show the highest expansion of temperate species within the last glacial. However, Heinrich events (HE), characterized by highest concentrations of ice-rafted debris (IRD) in marine sediments, are identified in eastern Anatolia by AP values not lower and high steppe components not more abundant than during DO stadials. In addition, this work is a first attempt to establish a continuous microscopic charcoal record over the last glacial in the Near East, which documents an initial immediate response to millennial-scale climate and environmental variability and enables us to shed light on the history of fire activity during the last glacial.

High-resolution multi-proxy record of the last interglacial period from Lake Van, eastern Anatolian high plateau, Turkey

A high-resolution multi-proxy record from Lake Van, eastern Anatolia, derived from a lacustrine sequence cored at the 357 m deep Ahlat Ridge (AR), allows a comprehensive view of paleoclimate and environmental history in the continental Near East during the last interglacial (LI). We combined paleovegetation (pollen), stable oxygen isotope (d18Obulk) and XRF data from the same sedimentary sequence, showing distinct variations during the period from 135 to 110 ka ago leading into and out of full interglacial conditions. The last interglacial plateau, as defined by the presence of thermophilous steppe-forest communities, lasted ca. 13.5 ka, from ~129.1-115.6 ka BP. The detailed palynological sequence at Lake Van documents a vegetation succession with several climatic phases: (I) the Pistacia zone (ca. 131.2-129.1 ka BP) indicates summer dryness and mild winter conditions during the initial warming, (II) the Quercus-Ulmus zone (ca. 129.1-127.2 ka BP) occurred during warm and humid climate conditions with enhanced evaporation, (III) the Carpinus zone (ca. 127.2-124.1 ka BP) suggest increasingly cooler and wetter conditions, and (IV) the expansion of Pinus at ~124.1 ka BP marks the onset of a colder/drier environment that extended into the interval of global ice growth. Pollen data suggest migration of thermophilous trees from refugial areas at the beginning of the last interglacial. Analogous to the current interglacial, the migration documents a time lag between the onset of climatic amelioration and the establishment of an oak steppe-forest, spanning 2.1 ka. Hence, the major difference between the last interglacial compared to the current interglacial (Holocene) is the abundance of Pinus as well as the decrease of deciduous broad-leaved trees, indicating higher continentality during the last interglacial. Finally, our results demonstrate intra-interglacial variability in the low mid-latitudes and suggest a close connection with the high-frequency climate variability recorded in Greenland ice cores.

U and Th concentrations and isotope ratios of samples from ODP Leg 166

Constraining the history of seawater (234U/238U) is important because this ratio is used to assess the validity of U/Th ages, and because it provides information about the past rate of physical weathering on the continents. This study makes use of U-rich slope sediments from the Bahamas in an attempt to reconstruct seawater (234U/238U) for the last 800 kyr. For the last 360 kyr, U/Th dating of these sediments provides ages and initial (234U/238U) values. Sixty-seven samples, largely from marine highstands, have initial (234U/238U) which scatter somewhat about the modern seawater value (~1.145) but neither this scatter nor the average value increases with age of sample. These data contrast with published coral data and suggest that seawater (234U/238U) has remained within 15? of the modern value for the last 360 kyr. This confirms the rejection of coral U/Th ages where the initial (234U/238U) is significantly different from modern seawater. Data from older highstands, dated with delta18O stratigraphy or by the presence of the Brunhes/Matuyama (B/M) reversal at 780 kyr, allow seawater (234U/238U) to be assessed prior to the range of the 230Th chronometer. Unfortunately, diagenetic scatter in the data between the B/M reversal and 360 kyr is rather large, probably relating to low U concentrations for these samples. But there is no indication of a trend in seawater (234U/238U) with age. High U samples from close to the B/M reversal show less diagenetic scatter and an initial (234U/238U) that averages 1.102. This lower value can be explained by lower seawater (234U/238U) at the time of the B/M reversal, or by progressive loss of 234U from the sediment by alpha-recoil. A simple box model is presented to illustrate the response of seawater (234U/238U) to variations in riverine input, such as might be caused by changes in continental weathering. Comparison of the Bahamas (234U/238U) data with model results indicates that riverine (234U/238U) has not varied by more than 65? for any 100 kyr period during the last 360 kyr. It also indicates that the ratio of physical to chemical weathering on the continents has not been higher than at present for any extended period during the last 800 kyr.

Paleomagnetic, stable oxygen isotope ratios, and U/Th activities of ODP Site 172-1062

Geomagnetic excursions are recognized as intrinsic features of the Earth's magnetic field. High-resolution records of field behaviour, captured in marine sedimentary cores, present an opportunity to determine the temporal and geometric character of the field during geomagnetic excursions and provide constraints on the mechanisms producing field variability. We present here the highest resolution record yet published of the Blake geomagnetic excursion (~125 ka) measured in three cores from Ocean Drilling Program (ODP) Site 1062 on the Blake-Bahama Outer Ridge. The Blake excursion has a controversial structure and timing but these cores have a sufficiently high sedimentation rate (~10cm/ka) to allow detailed reconstruction of the field behaviour at this site during the excursion. Palaeomagnetic measurements of the cores reveal rapid transitions (<500 yr) between the contemporary stable normal polarity and a completely reversed state of long duration which spans a stratigraphic interval of 0.7 m. We determine the duration of the reversed state during the Blake excursion using oxygen isotope stratigraphy, combined with 230Th excess measurements to assess variations in the sedimentation rates through the sections of interest. This provides an age and duration for the Blake excursion with greater accuracy and with constrained uncertainty. We date the directional excursion as falling between 129 and 122 ka with a duration for the deviation of 6.5±1.3 kyr. The long duration of this interval and the fully reversed field suggest the existence of a pseudo-stable, reversed dipole field component during the excursion and challenge the idea that excursions are always of short duration.

X-ray fluorescence scanning of discrete samples on the Schwalbenberg II loess-paleosol sequence, raw data, magnetic susceptibility, organic carbon and U-ratio as grainsize index

The Schwalbenberg II loess-paleosol sequence (LPS) denotes a key site for Marine Isotope Stage (MIS 3) in Western Europe owing to eight succeeding cambisols, which primarily constitute the Ahrgau Subformation. Therefore, this LPS qualifies as a test candidate for the potential of temporal high-resolution geochemical data obtained X-ray fluorescence (XRF) scanning of discrete samplesproviding a fast and non-destructive tool for determining the element composition. The geochemical data is first contextualized to existing proxy data such as magnetic susceptibility (MS) and organic carbon (Corg) and then aggregated to element log ratios characteristic for weathering intensity [LOG (Ca/Sr), LOG (Rb/Sr), LOG (Ba/Sr), LOG (Rb/K)] and dust provenance [LOG (Ti/Zr), LOG (Ti/Al), LOG (Si/Al)]. Generally, an interpretation of rock magnetic particles is challenged in western Europe, where not only magnetic enhancement but also depletion plays a role. Our data indicates leaching and top-soil erosion induced MS depletion at the Schwalbenberg II LPS. Besides weathering, LOG (Ca/Sr) is susceptible for secondary calcification. Thus, also LOG (Rb/Sr) and LOG (Ba/Sr) are shown to be influenced by calcification dynamics. Consequently, LOG (Rb/K) seems to be the most suitable weathering index identifying the Sinzig Soils S1 and S2 as the most pronounced paleosols for this site. Sinzig Soil S3 is enclosed by gelic gleysols and in contrast to S1 and S2 only initially weathered pointing to colder climate conditions. Also the Remagen Soils are characterized by subtle to moderate positive excursions in the weathering indices. Comparing the Schwalbenberg II LPS with the nearby Eifel Lake Sediment Archive (ELSA) and other more distant German, Austrian and Czech LPS while discussing time and climate as limiting factors for pedogenesis, we suggest that the lithologically determined paleosols are in-situ soil formations. The provenance indices document a Zr-enrichment at the transition from the Ahrgau to the Hesbaye Subformation. This is explained by a conceptual model incorporating multiple sediment recycling and sorting effects in eolian and fluvial domains.

U-Th dating of marine sediments from the Bahamas slope

In order to understand the driving forces for Pleistocene climate change more fully we need to compare the timing of climate events with their possible forcing. In contrast to the last interglacial (marine isotope stage (MIS) 5) the timing of the penultimate interglacial (MIS 7) is poorly constrained. This study constrains its timing and structure by precise U-Th dating of high-resolution delta18O records from aragonite-rich Bahamian slope sediments of ODP Leg 166 (Sites 1008 and 1009). The major glacial-interglacial cycles in delta18O are distinct within these cores and some MIS 7 substages can be identified. These sediments are well suited for U-Th dating because they have uranium concentrations of up to 12 ppm and very low initial 230Th contributions with most samples showing 230Th/232Th activity ratio of >75. U and Th concentrations and isotope ratios were measured by thermal ionisation mass spectrometry and multiple collector inductively coupled plasma mass spectrometry, with the latter providing dramatically better precision. Twenty-nine of the 41 samples measured have a delta234U value close to modern seawater suggesting that they have experienced little diagenesis. Ages from 27 of the 41 samples were deemed reliable on the basis of both their U and their Th isotope ratios. Ages generally increase with depth, although we see a repeated section of stratigraphy in one core. Extrapolation of constant sedimentation rate through each substage suggests that the peak of MIS 7e lasted from ~237 to 228 ka and that 7c began at 215 ka. This timing is consistent with existing low precision radiometric dates from speleothem deposits. The beginning of both these substages appears to be slightly later than in orbitally tuned timescales. The end of MIS 7 is complex, but also appears to be somewhat later than is suggested by orbitally tuned timescales, although this event is not particularly well defined in these cores.

U-series ages from calcitic cold-water corals from the Amundsen Sea

Radiocarbon and uranium-thorium dating results are presented from a genus of calcitic Antarctic cold-water octocorals (family Coralliidae), which were collected from the Marie Byrd Seamounts in the Amundsen Sea (Pacific sector of the Southern Ocean) and which to date have not been investigated geochemically. The geochronological results are set in context with solution and laser ablation-based element/Ca ratios (Li, B, Mg, Mn, Sr, Ba, U, Th). Octocoral radiocarbon ages on living corals are in excellent agreement with modern ambient deep-water D14C, while multiple samples of individual fossil coral specimens yielded reproducible radiocarbon ages. Provided that local radiocarbon reservoir ages can be derived for a given time, fossil Amundsen Sea octocorals should be reliably dateable by means of radiocarbon. In contrast to the encouraging radiocarbon findings, the uranium-series data are more difficult to interpret. The uranium concentration of these calcitic octocorals is an order of magnitude lower than in the aragonitic hexacorals that are conventionally used for geochronological investigations. While modern and Late Holocene octocorals yield initial d234U in good agreement with modern seawater, our results reveal preferential inward diffusion of dissolved alpha-recoiled 234U and its impact on fossil coral d234U. Besides alpha-recoil related 234U diffusion, high-resolution sampling of two fossil octocorals further demonstrates that diagenetic uranium mobility has offset apparent coral U-series ages. Combined with the preferential alpha-recoil 234U diffusion, this process has prevented fossil octocorals from preserving a closed system U-series calendar age for longer than a few thousand years. Moreover, several corals investigated contain significant initial thorium, which cannot be adequately corrected for because of an apparently variable initial 232Th/230Th. Our results demonstrate that calcitic cold-water corals are unsuitable for reliable U-series dating. Mg/Ca ratios within single octocoral specimens are internally strikingly homogeneous, and appear promising in terms of their response to ambient temperature. Magnesium/lithium ratios are significantly higher than usually observed in other deep marine calcifiers and for many of our studied corals are remarkably close to seawater compositions. Although this family of octocorals is unsuitable for glacial deep-water D14C reconstructions, our findings highlight some important differences between hexacoral (aragonitic) and octocoral (calcitic) biomineralisation. Calcitic octocorals could still be useful for trace element and some isotopic studies, such as reconstruction of ambient deep water neodymium isotope composition or pH, via boron isotopic measurements.