Die stabilen Isotopenverhältnisse von Sauerstoff und Kohlenstoff (¹⁸O/¹⁶O und ¹³C/¹²C) in atmosphärischem Kohlendioxid sind besonders geeignet, um den CO₂ Kreislauf zu untersuchen. Vor einigen Jahren wurde die Hypothese aufgestellt, dass die 3- Sauerstoffisotopen-Verhältnisse (¹⁷O/¹⁶O und ¹⁸O/¹⁶O) von troposphärischem Kohlendioxid ein neuer Isotopenindikator für die terrestrische Bruttoprimärproduktion ist. In dieser Arbeit wird untersucht, ob und inwieweit dieser neuartige Isotopenindikator konventionelle stabile Isotopenuntersuchungen von troposphärischem Kohlendioxid ergänzen kann. <br/> Die vorliegende Arbeit gliedert sich in vier Teile: (i) Die Entwicklung einer analytischen Methode, mit der die Sauerstoffisotopie (¹⁷O/¹⁶O, ¹⁸O/¹⁶O) von Kohlendioxid mit höchster Präzision gemessen werden kann. (ii) Eine experimentelle Untersuchung zum 3- Sauerstoffisotopen-Austausch zwischen CO₂ und Wasser. Dieser Austauschprozess ist von grundlegender Bedeutung für die Isotopen-Signatur von troposphärischem CO₂. (iii) Eine Studie zur 3-Sauerstoffisotopen-Zusammensetzung von Kohlendioxid aus Verbrennung mit einem besonderen Fokus auf anthropogene CO₂ Emissionen. (iv) Abschließend werden troposphärische CO₂ Daten vorgestellt und mit einem globalen Massenbilanzmodell verglichen. <br/> In Kapitel 2 wird die neuartige Methode zur 3-Sauerstoffisotopen-Analyse von CO₂ beschrieben. Diese Methode ermöglicht es, kleinste Variationen in troposphärischem Kohlendioxid und den unterschiedlichen CO₂ Quellen zur Troposphäre zu untersuchen. Die Methode beruht auf Isotopenäquilibrierung zwischen CO₂ und CeO₂ bei erhöhter Temperatur (T = 685 °C) und anschließender Laser-Fluorinierung des äquilibrierten Cerdioxids. Der freigesetzte Sauerstoff wird anschließend massenspektrometrisch auf seine 3-Sauerstoffisotopen-Zusammensetzung untersucht. Die Sauerstoffisotopie (¹⁷O/¹⁶O, ¹⁸O/¹⁶O) der Kohlendioxid Probe kann aus der Isotopie des CeO2 berechnet werden. Die Messgenauigkeit konnte im Vergleich zu früheren Methoden um etwa eine Größenordnung verbessert werden. <br/> Die Sauerstoffisotopie (¹⁷O/¹⁶O, ¹⁸O/¹⁶O) von troposphärischem Kohlendioxid wird hauptsächlich durch den Isotopenaustausch zwischen CO₂ und Wasser in Pflanzenblättern, Böden und in der obersten Meeresschicht bestimmt. Daher widmet sich Kapitel 3 der experimentellen Bestimmung der Gleichgewichtsfraktionierung (¹⁷O/¹⁶O, ¹⁸O/¹⁶O) zwischen CO₂ und Wasser bei drei unterschiedlichen Temperaturen (2 °C, 23 °C und 37 °C). Die experimentellen Ergebnisse stimmen mit theoretischen Berechnungen überein. Die Kenntnis dieses Gleichgewichtsfraktionierungsprozesses ist eine Grundvoraussetzung, um die 3-Sauerstoffisotopen-Zusammensetzung der natürlichen CO₂ Quellen aus der Biound Hydrosphäre abzuschätzen. <br/> In Kapitel 4 werden die experimentellen Ergebnisse zur 3-Sauerstoffisotopen- Zusammensetzung von Kohlendioxid aus Verbrennung dargestellt (Propan-Butan- Verbrennung, Holzverbrennung, Autoabgase und CO₂ aus Atemluft). Die Ergebnisse zeigen, dass bei Hochtemperatur-Verbrennungsprozessen die Sauerstoffisotopie von Luft- O2 (¹⁷O/¹⁶O, ¹⁸O/¹⁶O) größtenteils auf das Kohlendioxid übertragen wird. Bei niedrigen Verbrennungstemperaturen, wie der Holzverbrennung, wird die Sauerstoffisotopen- Zusammensetzung des freigesetzten Kohlendioxids auch durch CO₂-Wasser Äquilibrierung und andere Sauerstoffquellen, wie z.B. im Holz gebundener Sauerstoff, beeinflusst. Die Sauerstoffisotopen-Zusammensetzung von Kohlendioxid aus Atemluft wird hingegen nur durch den Isotopenaustausch mit Körperwasser bestimmt. Die experimentellen Daten zeigen, dass man anthropogenes Kohlendioxid anhand seiner Sauerstoffisotopie (¹⁷O/¹⁶O, ¹⁸O/¹⁶O) eindeutig von Kohlendioxid aus natürlichen Quellen unterscheiden kann. <br/> In Kapitel 5 werden die ersten hoch-präzisen 3-Sauerstoffisotopen-Analysen von troposphärischem Kohlendioxid vorgestellt. Der Datensatz von CO₂ Proben aus Göttingen zeigt eine deutliche zeitliche Variation in der 3-Sauerstoffisotopen-Zusammensetzung. Diese zeitliche Schwankung stimmt nur teilweise mit der saisonalen Variation des ¹⁸O/¹⁶O Verhältnisses von troposphärischem CO₂ überein. Messungen von CO₂ Proben vom Brocken (1140 m, Harz, Deutschland) stimmen mit den gemessen Daten in Göttingen überein. Die Massenbilanz Vorhersage für die 3-Sauerstoffisotopen-Zusammensetzung von troposphärischem CO₂ stimmt nur teilweise mit den gemessenen Daten überein. Die Modellierung legt nahe, dass die zeitlichen Variationen in der 3-Sauerstoffisotopen- Zusammensetzung nicht durch saisonale Schwankungen der biologischen Aktivität erklärt werden können, stattdessen könnte der Zustrom von stratosphärischem CO₂ die zeitlichen Schwankungen verursachen. <br/> Diese Untersuchung bereitet die Grundlage für 3-Sauerstoffisotopen Analysen von troposphärischem Kohlendioxid und deren aussagekräftige Interpretation. Allerdings können nicht alle Merkmale der gemessenen Isotopendaten erklärt werden, es werden künftig weitere Untersuchungen notwendig sein.

Revised chronologies from Moroccan cave sites have raised questions concerning the timing of changes in human cultural behaviour in relation to past climate shifts. However, many of the inferences about past moisture regimes are based on external records. Therefore, this thesis aimed to develop a palaeoclimate record using oxygen and carbon isotope values (d18O and d13C) in Gerbillinae (gerbil) teeth from two Late Pleistocene cave sites, El Harhoura 2 and Taforalt, in Morocco. Since small mammals are not commonly used to construct proxy climate records, a modern isotope study was undertaken in northwestern Africa to understand the influences on the stable isotope composition of small mammal tissues in semi-arid and arid settings. The results from the modern study show that d18O composition of gerbil teeth is strongly correlated with mean annual precipitation (MAP), and therefore in arid settings reflects moisture availability. Predictably, the d13C values of the gerbil teeth reflected C3 and C4 dietary inputs, but arid and mesic sites could not be distinguished because of the high variability displayed in d13C. The d18O isotope-based MAP reconstructions suggest that the Mediterranean coastal region of North Africa did not experience hyper-arid conditions during the Late Pleistocene. The d13C values of the gerbil teeth show that C3 vegetation dominated in the Late Pleistocene, but there was a small amount C4 vegetation present at Taforalt. This indicates that small mammals are extremely sensitive to discreet shifts in past vegetation cover. Both the modern and archaeological studies demonstrated that the isotope values of molars and incisors differed. The results indicate that tooth choice is an important consideration for applications as proxy Quaternary records, but also highlights a new potential means to distinguish seasonal contexts. Comparisons of proxy climate records and cultural sequences at Taforalt and El Harhoura 2 show that Middle Stone Age occupations of both sites occurred during relatively humid and arid climate phases. The transition to the Later Stone Age appears to have taken place during a period of increased aridity, hinting that this cultural transition may be related to changing environmental conditions.

The global paleoclimate archive is lacking in tropical dendrochronology studies as a result of limitations from inconsistent tree-ring production imposed by precipitation-driven seasonality. The slash pine, Pinus elliottii Engelm. var. densa, is the dominant canopy species of Big Pine Key (BPK) rocklands and has been shown to produce complicated, but distinct, ring structures; however, traditional dendrochronology studies have not established correlations between ring width measurements and major climate drivers controlling South Florida precipitation. My study utilized the carbon (δ13C) and oxygen (δ18O) isotope records in the α-cellulose component of tree-rings to extract information about the physiological responses of trees to climate and tropical cyclone activity. The δ13C measurements in the earlywood and latewood of four P. elliottii var. densa trees were used to build a chronology (1922-2005) and to distinguish annual growth from intra-annual density fluctuations (IADFs). Empirical orthogonal functions were used to determine individual response to precipitation, El Niño-Southern Oscillation (ENSO), and the Atlantic Multidecadal Oscillation (AMO). There is a distinct relationship between the δ13C values of cellulose and ENSO; however the nature (direct vs. inversely correlated) is temporally controlled by the prevailing phase of the AMO. The appearance of some IADFs coincide with the timing of El Niño winters occurring during the cool AMO phase, resulting in enriched δ13C values. The additional precipitation may encourage tree growth, but subsequent dry periods may slow growth and cause the tree to employ water-conservation strategies. Tree growth is influenced by the major climate drivers and the control they exert over the timing of precipitation; however, growth is ultimately controlled by the microenvironment surrounding individual trees. The δ18O and δ13C values of the latewood cellulose were compared to tropical cyclone activity occurring within a 100km radius of BPK. Tropical storms and depressions appeared as anomalously depleted values in the δ18O residual record, reflecting large amounts of tropical rain. The effects of hurricanes varied by storm; however, many of the major hurricanes (category 3-5) were preserved as an enrichments in the δ13C value of the following earlywood season. The application of stable isotope analyses greatly increases the breadth of paleoclimate information available from the trees.

This thesis focuses on frothy, felsic xenoliths called ‘xenopumice’, that were retrieved from La Palma during a 10–day field campaign in December 2018. There are only few descriptions of these frothty xenoliths, and a consensus on their origin has not yet been achieved. Furthermore, the xenopumice–bearing vents of the pre–historic eruption of Las Indias and the 1949 eruption of Cumbre Vieja have experienced explosive phreatomagmatism, implying a possible connection between the presence of xenopumice and high–energy volcanism. The sampled suite consists of 18 xenopumice specimens and one ash sample from Las Indias, 11 xenoliths and one ash sample from the 1949 eruption, as well as 8 samples of phonolitic xenoliths and one lava sample from the 1585 Jedey eruption. The mineralogy, textural features, elemental composition, and oxygen isotopes show discrepancy between the sampled xenopumices. The samples from Las Indias and two samples from the 1949 eruption are quartz bearing. These samples have furthermore a high silica content (64 to 74 SiO2 wt. %) and high oxygen isotope ratios of 11.1 to 18.3 ‰, coinciding with typical values of sedimentary rock. The remaining samples from the 1949 eruption comprise mainly feldspars, with some samples showing 120° triple junction grain boundaries. These samples have SiO2 concentrations from 50 to 64 wt. %, and oxygen isotope ratios that range from 3.4 to 11.7 ‰, which compare more closely with magmatic rather than with sedimentary protoliths. REE distribution trends display a similar compositional spectrum for all quartz bearing xenopumice samples, which are similar to average the REE content of continental crust. From these results it is proposed that the quartz bearing xenopumice are of sedimentary origin, while the feldspar–rich samples are primarily igneous rocks associated with the formation of La Palma. The frothy texture of the investigated xenopumice implies substantial degassing and expansion in the magmatic conduit of ca. 13 to 34 %. Such intense gas release may have profound effects on the eruptive mechanisms and styles, as it might increase the risk of explosive activity. For future risk assessment on La Palma and the other Canary Islands it is thus important to understand magma storage and potential interaction with surrounding bedrock, as this can cause an otherwise calm, mafic eruption to become explosive in nature. / La Palma är en c. 2 miljoner år gammal vulkanö som tillhör ökedjan Kanarieöarna. Den här studien fokuserar på felsiska, pimpstensliknande xenoliter som hämtats från La Palma. Xenolit betyder främmande sten, vilket innebär att de inte formats på samma sätt som lavan som burit dem till ytan. Hur de felsiska xenoliterna från La Palma formats och vart de kommer från, är frågor som inte besvarats förut. Förekomsten av felsiska xenoliter kan dessutom kopplas samman med utbrott av explosiv karaktär. La Palma har generellt inte explosiv vulkanism, så därför är denna koppling mycket intressant. Projektets syfte är därmed att avgöra vart xenoliterna kommer ifrån, hur de kan ha påverkat utbrottet, och om det finns en koppling mellan explosiva utbrott och formationen av felsiska xenoliter. Från analyser av xenoliternas mineralogi och kemiska sammansättning, är det tydligt att inte alla xenoliter har samma ursprung. Vissa består främst av fältspater, och har en kemisk sammansättning som mer liknar magmatisk sten. De andra proverna innehåller kvarts och har höga syreisotopvärden, vilket indikerar ett sedimentärt ursprung, då kvarts primärt inte formas genom magmatiska processer på Kanarieöarna. Den pimpstensliknande texturen hos både magmatiska och sedimentära xenoliter, indikerar att gas har bildats när xenoliterna togs upp av magman. En sådan gasbildning kan kraftigt öka trycket i magmakammaren och orsaka explosiva utbrott, vilket tyder på att förekomsten av de pimpstensliknande xenoliterna från La Palma kan ha påverkat det resulterande utbrottet. För att i framtiden bättre kunna avgöra den potentiella risken som ett utbrott utgör, måste interaktionen mellan kringliggande berg och magma studeras noggrannare.

Katla volcano, South Iceland, is a bimodal volcanic system hosting an unusual high number of silicic rocks within a basaltic rift setting. The petrogenesis of silica-rich rocks at Katla is controversial and two end-member hypotheses have been suggested. One model involves closed-system fractional crystallisation from a basaltic parental magma and the other emphasises partial melting of hydrothermally altered basaltic crust. To contribute to this debate, this study provides new δ18O data from a suite of high-silica eruptive rocks with complementary basaltic eruptive material from the Katla caldera complex. Petrographically, the rocks of this study display evidence of partial melting indicated by symplectites in xenoliths as well as variously extensive resorption features. The new δ18O data display a range of the basaltic suite between +4.3 and +8.5‰ (n=15), whereas the few intermediate samples range between +4.1 and +5.9‰ (n=3). The silicic xenoliths available in the study range between -4.9 and -2.3‰ (n=4) while the silicic eruptive material ranges between +2.7 and +6.4‰ (n=30). The dominant part of the high-silica eruptive material (97%) is considered as low-δ18O (≤5.0‰) and plots below typical MORB-type magmas (5.7‰ ±0.3). The wide range of δ18O values of the Katla silicic suite is not possible to explain by closed-system fractional crystallisation and to determine the origin of the high-silica Katla rocks, the new δ18O ratios were utilised in fractional crystallisation (FC) and assimilation and fractional crystallisation (AFC) modelling. The results indicate that a two-stage magma evolution process can explain the origin of the high-silica low-δ18O Katla rocks. The early-stage involves differentiation at deep- to mid-crustal levels by fractionation and assimilation processes involving both high and low δ18O crustal materials, allowing production of intermediate to felsic magmatic compositions. Following this deep differentiation, evolved magmas experience δ18O modification at shallow crustal levels by assimilation of low-δ18O hydrothermally altered crustal material or interaction with low-δ18O waters. Such a two-stage magma evolution process is consistent with geophysical and geobarometric studies of a two-tiered magma plumbing system beneath Katla that supports a mid- to deep-crustal basaltic magma storage system and simultaneous shallow crustal silicic magma storage. / Vulkanen Katla på södra Island är ett bimodalt vulkaniskt system med ovanligt mycket kiselrika bergarter i en basaltisk riftmiljö. De kiselrika bergarterna från Katla har ett kontroversiellt ursprung och två huvudhypoteser har blivit föreslagna. En modell innefattar fraktionerad kristallisation av en basaltisk ursprungsmagma och den andra modellen betonar rollen av partiell smältning av hydrotermiskt altererad basaltisk skorpa. Som en del i denna debatt bidrar denna studie med ny δ18O-data från en serie kiselrikt eruptivt material med komplimenterande basaltiskt eruptivt material från Katlas kalderakomplex. Det studerade materialet i denna studie påvisar tecken på partiell smältning vilket indikeras av symplektiter i xenoliter samt resorptionstecken av olika omfattning. De nya δ18O-värdena för den basaltiska serien varierar mellan +4,3 och +8,5‰ (n=15), medan de få intermediära proverna varierar mellan +4,1 och +5,9‰ (n=3). De kiselrika xenoliterna i denna studie varierar mellan 4,9 och -2,3‰ (n=4) medan det kiselrika eruptiva materialet varierar mellan +2,7 och +6,4‰ (n=30). Den största delen av det kiselrika eruptiva materialet (97%) har låga δ18O-värden (≤5,0‰) som är lägre än typisk basalt från mittoceanryggar (5,7‰ ±0,3). Det breda intervallet av δ18O-värden hos det kiselrika eruptiva materialet är inte möjligt att förklara genom fraktionerad kristallisation och för att undersöka ursprunget användes de nya δ18O-värdena i modeller för fraktionerad kristallisation (FC) samt assimilering och fraktionerad kristallisation (AFC). Resultatet indikerar att en utvecklingsprocess för magman i två steg kan förklara ursprunget av det kiselrika eruptiva materialet med låga δ18O-värden från Katla. Det tidiga skedet involverar differentiering på medeldjupa till djupa nivåer i skorpan genom fraktionerings- och assimilationsprocesser som involverar material från skorpan med både höga och låga δ18O-värden, vilket bidrar till produktion av intermediära till kiselrika magmakompositioner. Efter denna djupa differentieringsprocess genomgår utvecklade magmor en förändring i δ18O-värden högt upp i skorpan genom assimilation av hydrotermiskt altererat material med låga δ18O-värden eller genom interaktion med vatten med låga δ18O-värden. Denna tvåstegsprocess stöds av geofysiska och geobarometriska studier av ett tvådelat magmasystem under Katla vilka talar för ett medeldjupt till djupt basaltiskt magmalagringsutrymme och ett samtida grunt kiselrikt magmalagringsutrymme.

No description available.

No description available.

In this dissertation, I explore elements of the changing Arctic Ocean through the application of Stable Isotope, Noble Gas Isotopes, and sulfur hexafluoride (SF6) to better understand ice dynamics for freshwater balance, air/sea gas exchange and ocean circulation. For the tracer studies of stable isotope fractionation, our approach is to use sea ice core data to determine the stable oxygen isotope effective fractionation coefficient. The result is an average value close to 2.2 ‰, which is compared to literature values. For the tracer studies of air/sea gas exchange, we use Neon (Ne) and Helium (He) isotope data sets collected in the ‘Switchyard’ region of the Arctic Ocean between 2005 and 2013 and in the Greenland and Norwegian seas between 1994 and 1999. The Switchyard data show a distinct excess in Ne concentrations in the upper waters. We hypothesize that rejection of Ne during sea ice formation accounts for the Ne excess in the Switchyard area of the Arctic Ocean. Based on this hypothesis we estimate sea-ice formation rates by integrating the Ne excess from the surface to the Atlantic Water layer. The resulting amount of excess Ne corresponds to formation of a nearly 4 m thick sea ice layer. We compare the sea ice formation obtained from the Ne excess method with an independent estimate based on oxygen isotope ratio anomalies ?18O, which is nearly 6.07 m. The difference in the sea ice formation estimated by these two methods indicates loss of Ne through leads. We estimate that the gas exchange rate through the sea-ice cover is ca. 11.3 percent per year. The gas exchange rate through sea-ice covered water would be 0.015 meters per day. For the tracer studies of mean residence times, we analyzed tritium (3H), helium isotope (3He and 4He) and sulfur hexafluoride (SF6) samples collected in the ‘Switchyard’ region of the Arctic Ocean between 2008 and 2013. We calculated apparent tracer ages using the 3H/3He ratios and the partial pressure of SF6 and compare their values for the depth interval between the surface and the core of the Atlantic Water layer. The apparent tracer ages range from zero to about 30 years. Generally, the linear correlation between the 3H/3He and SF6 apparent ages was strong, with the coefficient of determination R2 of 0.94. We explore deviations from this linear trend and discuss them in the context of mixing, air-sea gas exchange, and the impact of sea ice formation on the helium and SF6 gas balances in the surface mixed layer.

[NiFe] hydrogenases are metalloenzymes that act as highly efficient molecular electrocatalysts for the interconversion of protons and molecular hydrogen. Unlike any other known molecular electrocatalyst, the members of a subgroup of respiratory membrane-bound [NiFe] hydrogenases are able to maintain H₂ catalysis in the sustained presence of O₂. This O₂-tolerance depends on the ability to respond to oxidative inactivation by O₂ by exclusively forming rapidly reactivated active site states, thus implying a catalytic cycle in which O₂ acts as a competing substrate to H₂. Using isotope ratio mass spectrometry it is proven that the O2-tolerant Escherichia coli Hydrogenase 1 responds to O₂ attack by acting as a four-electron oxidoreductase, catalysing the reaction 2 H₂ + O₂ → 2 H₂O, equivalent to hydrogen combustion. Special features of the enzyme’s electron relay system enable delivery of the required electrons. A small fraction of the H₂O produced arises from side reactions proceeding via reactive oxygen species, an unavoidable consequence of the presence of low-potential relay centres that release electrons from H₂ oxidation. While the ability to fully reduce O₂ to harmless H₂O at the active site to generate the rapidly reactivated state Ni-B, determines if a hydrogenase is O₂-tolerant, the ratio of oxidative inactivation to reductive reactivation rates determines how tolerant the enzyme is. It is shown by protein film electrochemistry that the (αβ)₂ dimeric assembly of Hyd-1 plays an important role in O₂-tolerance by aiding reactivation of one catalytic unit through electron transfer from the other. The teamwork between two redundant partners implicates a new role for dimerisation and represents a new example of cooperativity in biology. Finally, the non-natural amino acid p-azido-L-phenylalanine was synthesised and incorporated into Hyd-1, testing the possibility of introducing labels at specific sites.

Submitted by William Justo Figueiro (williamjf) on 2015-07-15T20:29:02Z No. of bitstreams: 1 14c.pdf: 18447268 bytes, checksum: cb27bcfcdf1b467b658d2ece3ae7777b (MD5) / Made available in DSpace on 2015-07-15T20:29:02Z (GMT). No. of bitstreams: 1 14c.pdf: 18447268 bytes, checksum: cb27bcfcdf1b467b658d2ece3ae7777b (MD5) Previous issue date: 2012-11-12 / Nenhuma / O presente estudo apresenta a taxonomia, bioestratigrafia e paleoecologia dos foraminíferos planctônicos e bentônicos recuperados no intervalo Aptiano superiorAlbiano da sucessão dominantemente carbonática do Deep Sea Drilling Project (DSDP) Site 364, localizado na bacia de Kwanza (costa afora de Angola). Foram identificadas 30 espécies de foraminíferos planctônicos e 42 espécies de foraminíferos bentônicos. Com base nas assembleias de foraminíferos planctônicos, a seção sedimentar estudada foi subdividida em diversas biozonas, abrangendo as idades Aptiano tardio ao Albiano, da Zona Hedbergella trocoidea a Zona Pseudothalmanninella ticinensis. Uma conspícua discordância foi identificada no core 31, compreendendo do topo do Albiano inferior à base do Albiano superior. A composição específica das assembleias de foraminíferos planctônicos as caracteriza como assembleias marinhas de águas rasas e permite a inferência do domínio de condições mesotróficas a eutróficas ao longo do intervalo estudado. As associações aptianas de foraminíferos planctônicos apresentam afinidade paleobiogeográfica tetiana, suportando um influxo de água superficial tetiana no setor restrito (ao norte da Cadeia de Walvis-Elevação do Rio Grande) do Oceano Atlântico Sul setentrional já no Aptiano tardio. Tendências nos valores isotópicos de 13C, que devem ser cuidadosamente interpretadas devido a uma possível alteração diagenética, sugerem uma idade aptiana tardia (Zona Globigerinelloides algerianus) para o intervalo estratigráfico do core 42 ao core 37, no qual fósseis-guia tetianos estão ausentes, além de sugerir que os folhelhos negros da base do testemunho estudado (cores 42-39) podem ser correlatos ao evento anóxico do Aptiano tardio. Entre os foraminíferos planctônicos ocorre uma profunda mudança faunística na passagem Aptiano-Albiano, caracterizada por altas taxas de extinção seguidas por elevadas taxas de surgimento de espécies, além de uma significativa mudança no padrão arquitetural das testas. Foram identificadas três associações de foraminíferos bentônicos, que parecem ser principalmente controladas por variações paleobatimétricas. A fauna de foraminíferos bentônicos pode ser classificada como uma Associação do tipo Marssonella, provavelmente relacionada a paleoprofundidades neríticas a batiais superiores, e também exibindo uma marcada afinidade paleobiogeográfica tetiana. / This work presents a taxonomic, biostratigraphic and paleoecologic study on the planktic and benthic foraminiferal faunas recovered from the late Aptian-late Albian carbonatedominated succession of Deep Sea Drilling Project (DSDP) Site 364, located in the Kwanza Basin (offshore Angola). Thirty planktic and 42 benthic foraminiferal species were identified herein. Based on planktic foraminiferal assemblages, the studied section was subdivided in a series of biozones, late Aptian to late Albian in age, from the Hedbergella trocoidea Zone to the Pseudothalmanninella ticinensis Zone. A remarkable unconformity was identified in core 31, spanning the latest early to earliest late Albian. The specific composition of the recovered planktic foraminiferal assemblages characterizes them as open marine epipelagic dwellers, and permits the suggestion of predominant mesotrophic to eutrophic environmental conditions throughout the studied stratigraphic succession. Aptian planktic foraminiferal assemblages present a significant Tethyan paleobiogeographic affinity, supporting a Tethyan surface-water influx into this restricted southeastern sector of the northern South Atlantic Ocean (north to the Walvis Ridge-Rio Grande Rise) back in the late Aptian. 13C trends, which have to be carefully interpreted due to possible diagenetic overprint, suggest a late Aptian age (Globigerinelloides algerianus Zone) for the stratigraphic interval from core 42 to about core 37, where Tethyan age-diagnostic foraminiferal species are missing, as well as that the black shale levels in cores 42-39 could be correlated to the “late Aptian anoxic event”. Among planktic foraminifera, a conspicuous faunal turnover occurs at the Aptian/Albian transition, characterized by high rates of extinctions followed by increasing rates of species originations and changes in tests’ architecture. Three benthic foraminiferal associations were identified, which seem to be mainly controlled by changes in paleobathymetry. Also, the studied benthic foraminiferal fauna could be classified as a Marssonella Association, probably related to neritic and upper bathyal paleodepths, also exhibiting a Tethyan paleobiogeographic affinity.