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The planktonic foraminiferal taxon Ticinella bejaouaensis Sigal, 1966 had long been an important zonal biomarker for the latest Aptian characterized by its large test, numerous (8–10) final-whorl chambers, and rugose test surface, usually with an umbilical cover-plate. Upon confirmation that Sigal's Madagascan holotype was actually from the upper Albian, this species was renamed as T. eubejaouaensis Randrianasolo and Anglada, 1998 using Sigal's Tunisian bejaouaensis paratype, which is late Aptian in age, as the new holotype. Following emendation of the genus, Paraticinella eubejaouaensis has recently become the standard usage. However, the validity of this species is still uncertain because the original designation was given in very obscure publication(s). Meanwhile, albeit tenuous, a presumable senior name “Paraticinella rohri ( Bolli, 1959 )” has recently been proposed in place of eubejaouaensis. Rigorous assessment of the original species designation of T. eubejaouaensis ascertains that the method of publication used does not comply with the criteria required in the International Code of Zoological Nomenclature, thereby making this species an invalid name, or nomen nudum. New backscattered scanning electron microscopic observations of the primary types of Praeglobotruncana rohri Bolli, 1959 reveal that this hitherto unattended species is indeed synonymous to “T. eubejaouaensis” particularly by exhibiting equatorially aligned rugosities on the wall surface, and that the holotype is sufficiently preserved and well qualified as the name-bearing type. The latest Aptian age of the rohri type level is robustly established by its co-occurrence with Pseudoplanomalina cheniourensis ( Sigal, 1952 ) and Hedbergella trocoidea ( Gandolfi, 1942 ) (= another rohri paratype). Upon confirmation of the absence of any potential nomenclatural acts for conservation of the junior name “[eu]bejaouaensis,” we are obliged to provide formal redescription and establish the valid, objective senior name Paraticinella rohri ( Bolli, 1959 ), the binomen that should be of mandatory use henceforth. Accordingly, the uppermost Aptian “[eu]bejaouaensis” Zone should be referred to as the “Pt. rohri Zone.” Having reviewed the supraspecific taxonomy, herein the type species of the genus Paraticinella is redefined as Pt. rohri, and the subfamily Pseudoplanomalininae is proposed.

The palaeogeographic setting of the studied Ain Medheker section represents an Early Campanian to Early Maastrichtian moderately deep carbonate shelf to distal ramp position with high rates of hemipelagic carbonate production, periodically triggered by mass-flow processes. Syndepositional extensional tectonic processes are confirmed to the Early Campanian. Planktonic foraminifera identified in thin sections and calcareous nannofossils allow the identification of the following biozones: Globotruncanita elevata, Contusotruncana plummerae (replacing former Globotruncana ventricosa Zone), Radotruncana calcarata, Globotruncana falsostuarti , and Gansserina gansseri . The following stable C-isotope events were identified: the Santonian/Campanian boundary Event, the Mid-Campanian Event, and the Late Campanian Event. Together with further four minor isotopic events, they allow for correlation between the western and eastern realms of Tunisia. Frequently occurring turbidites were studied in detail and discussed in comparison with contourites.

The evolution of planktic foraminifera in the Paleocene–Eocene time interval is characterized by a high rate of diversification after the major extinction event observed at the Cretaceous/Paleogene boundary. An accelerated speciation rate resulted in the appearance of several new genera. Phylogenetic relationships among many of genera are still poorly understood. This study investigates the origin and phylogeny of the genus Igorina , which is characterized by a thick, nonspinose and incrusted wall. Igorina appears in Subzone P3a (early late Paleocene) and disappears in Zone P11 (middle Eocene). To date, nine species have been assigned to the genus Igorina ( I. pusilla , I. trichotrocha , I. tadjikistanensis , I. convexa , I. albeari , I. laevigata, I. lodoensis , I. broedermanni , and I. anapetes ) based on both wall texture and morphologic similarities. However, the taxonomic identification at species level is affected by several problems, mainly those resulting from poor descriptions and illustrations of the primary type specimens of several species. This study reconstructs the phylogeny and evolution of the igorinids through cladistic analysis by applying the method of parsimony. Phylogenetic relationships of the species assigned to Igorina are determined through stratocladistic analysis by using a data matrix of 23 taxa (including key species of Acarinina ), 31 morphological characters (unordered), and a stratigraphic character (ordered) mapping the first occurrence of the taxa under investigation. The matrix (Appendix 1) was processed with PAUP* 4.0b10 software by using the heuristic search option to discover the most parsimonious trees. Results suggest that I. pusilla is the first representative of the Igorina lineage, and it is followed by I. laevigata , I. convexa , and I. albeari . Morphotypes of uncertain taxonomic identification have been coded and analyzed separately as morphotypes A–F to determine their ancestor-descendant relationships and to evaluate their validity as discrete species. As the result of our analysis, two new species are formally described as I. praecarinata (= morphotype A) and I. paraspiralis (= morphotypes C, E, and F). Finally, our analysis provides evidence that I. lodoensis , I. broedermanni , and I. anapetes are more closely related to Acarinina than to Igorina and clearly belong to a different lineage.

The Monte Orfano Conglomerate (MOC), exposed in the foothills of the Southern Alps (northern Italy), is one of the few outcrops of sediments documenting the Cenozoic tectonic evolution of the Alpine retrowedge. Calcareous nannofossil biostratigraphy allowed us to constrain the upper part of the MOC, formerly attributed to the Early-Middle Miocene in the type-locality, to the earliest Miocene (Neogene part of the NN1 nannofossil zone). A likely latest Oligocene age is therefore suggested for the bulk of the underlying conglomerates, whose base is not exposed. Deposition of the MOC can be placed within the post-collisional tectonic uplift of the Alps, documented in the Lake Como area by the Como Conglomerate (CC) at the base of the Gonfolite Lombarda Group, and supports the correlation with Upper Oligocene clastic sediments cropping out further to the East, in the Lake Garda and in the Veneto-Friuli areas (“molassa”). The remarkable difference in petrographic composition between the western (CC) and eastern (MOC) clastics deposited in the Alpine retro-foreland basin highlights the synchronous tectonic activity of two structural domains involving different crustal levels. Whilst the bulk of the CC, that straddles the Oligocene/Miocene boundary, records largely the tectonic exhumation of the Alpine axial chain crystalline complexes, the coeval MOC consists of detritus derived from the superficial crustal section (Triassic to Paleogene sedimentary rocks) of the Alpine retrowedge and constrains the onset of the post-collisional deformation phase of the Southern Alps as not younger than the Late Oligocene.

Based on examination of the type material deposited by Jacques Sigal at the Musee National d’Histoire Naturelle in Paris, we have validated the hypothesis of Randrianasolo and Anglada (1998) that the holotype and paratype of Ticinella bejaouaensis Sigal 1966 belong to two different species, the distributions of which do not overlap. Indeed, the holotype is of late Albian age and from Madagascar whilst the paratype is of a latest Aptian age and from Tunisia. Sigal’s paratype is here confirmed to be the holotype of the species eubejaouaensis Randrianasolo and Anglada, 1998. It displays a distinctive wall texture bearing perforation cones that coalesce to form irregularly arranged rugosities and ridges, which tend to parallel the periphery. In addition, flaps may cover the umbilical area. However, it lacks true umbilical supplementary apertures and therefore cannot be included in the genus Ticinella Reichel, 1950. The new genus Paraticinella , with Paraticinella eubejaouaensis as the type species, is here formalized to accommodate uppermost Aptian trochospiral individuals with a wall texture bearing perforation cones, rugosities, and ridges in patterns paralleling the margin, and possessing an umbilical cover-plate. Paraticinella eubejaouaensis evolved from Hedbergella trocoidea in the upper Aptian. The evolutionary trend is exemplified by the increasing number of chambers, by flattening of the spire height, by widening of the umbilicus with the appearance of a cover-plate, by acquisition of well-developed ridges on wall surfaces, and by the appearance of weakly developed infralaminal accessory apertures in later specimens of P. eubejaouaensis . A close study of the holotype of Ticinella bejaouaensis Sigal, 1966 reveals a substantial similarity in morphology and wall structure with Ticinella roberti and a lack of distinguishing criteria between the two species. Consequently, the species Ticinella bejaouaensis is invalidated and is considered to be a junior synonym of T. roberti . A third species was observed associated with Ticinella roberti and Biticinella breggiensis in Madagascar and Spain, and it is attributable to the genus Ticinella based on the presence of true umbilical supplementary apertures and a typical Ticinella wall structure (muricate to coarsely pustulose), while in gross morphology, it resembles Paraticinella eubejaouaensis . We have named this new taxon Ticinella moulladei . It differs from T. roberti by its thinner test, more numerous chambers, and wider umbilicus. Finally, the last zone of the uppermost Aptian must be renamed the Paraticinella eubejaouaensis Zone to replace Ticinella bejaouaensis , which is now considered to be an invalid taxon.

The early Aptian Oceanic Anoxic Event (OAE1a, 120 Ma) represents a geologically brief time interval in the mid-Cretaceous greenhouse world that is characterized by increased organic carbon accumulation in marine sediments, sudden biotic changes, and abrupt carbon-isotope excursions indicative of significant perturbations to global carbon cycling. The brevity of these drastic environmental changes (

GABAB-receptor (GABABR) mediated inhibition is important in regulating neuronal excitability. The paired-pulse transcranial magnetic stimulation (TMS) protocol of long-interval intracortical inhibition (LICI) likely reflects this GABABergic inhibition. However, this view is based on indirect evidence from electromyographic (EMG) studies. Here we combined paired-pulse TMS with simultaneous electroencephalography (paired-pulse TMS–EEG) and pharmacology to directly investigate mechanisms of LICI at the cortical level. We tested the effects of a conditioning stimulus (CS100) applied 100 ms prior to a test stimulus (TS) over primary motor cortex on TS-evoked EEG-potentials (TEPs). Healthy subjects were given a single oral dose of baclofen, a GABABR agonist, or diazepam, a positive modulator at GABAARs, in a placebo-controlled, pseudo-randomized double-blinded crossover study. LICI was quantified as the difference between paired-pulse TEPs (corrected for long-lasting EEG responses by the conditioning pulse) minus single-pulse TEPs. LICI at baseline (i.e. pre-drug intake) was characterized by decreased P25, N45, N100 and P180 and increased P70 TEP components. Baclofen resulted in a trend towards the enhancement of LICI of the N45 and N100, and significantly enhanced LICI of the P180. In contrast, diazepam consistently suppressed LICI of late potentials (i.e. N100, P180), without having an effect on LICI of earlier (i.e. P25, N45 and P70) potentials. These findings demonstrate for the first time directly at the system level of the human cortex that GABABR-mediated cortical inhibition contributes to LICI, while GABAAR-mediated inhibition occludes LICI. Paired-pulse TMS–EEG allows investigating cortical GABABR-mediated inhibition more directly and specifically than hitherto possible, and may thus inform on network abnormalities caused by disordered inhibition, e.g. in patients with schizophrenia or epilepsy.

New ages of rocks in the San Juan Islands, northwest Washington, significantly change our understanding of the evolution of the San Juan Islands thrust system. Re-examination of foraminifera-bearing mudstones at Richardson on Lopez Island indicates a late Aptian (112-115 Ma), not late Albian (100 Ma) age as currently presented in the literature. The age brackets of thrusting, marked by these pre-thrusting mudstones and 84-Ma post-thrusting sedimentary rocks, span a much longer period than previously thought, diminishing controls on rates of displacement in the thrust system and the timing of regional deformation in western Washington. New 40 Ar/ 39 Ar plateau ages of phengite in blueschist-facies meta-volcanic rock, also at Richardson, are 124 ± 0.7 Ma (2σ, late Barremian). These blueschist-facies volcanic rocks are in fault contact with the fossiliferous mudstones. Therefore, the blueschist-facies metamorphism at Richardson, previously inferred to be associated with the thrusting, now appears to have occurred prior to thrusting. Further, the Ar ages demonstrate that blueschist-facies fabric formed earlier than the thrust event and is therefore not directly useful in analyzing the thrusting kinematics. The Richardson 40 Ar/ 39 Ar age is similar to isotopic ages found in the eastern San Juan Islands and in the Shuksan blueschist terrane in the northwest Cascades, and thus fits into an emerging regional age pattern of blueschist-facies metamorphism during Late Jurassic - Early Cretaceous (up to Barremian) but not late Albian - Cenomanian. If this pattern is more broadly confirmed for the San Juan Islands, all the blueschist-facies metamorphism can be regarded as having formed in subduction zones elsewhere along the continental margin rather than in the anomalous setting of an on-land thrust system, as in the San Juan Islands. Resume : De nouveaux âges pour les roches des iles San Juan, dans le nord-ouest de l'etat de Washington, changent profondement notre comprehension de l'evolution du systeme de chevauchement San Juan. Un reexamen des mudstones foraminiferes, a Richardson, sur l'ile Lopez, indique un âge Aptien tardif (112-115 Ma) et non Albien tardif (100 Ma) tel qu'indique actuellement dans la litterature. Les plages d'âges pour le chevauchement, marquees par ces mudstones precedant le chevauchement et des roches sedimentaires 84 Ma posterieures au chevauchement, couvrent une periode beaucoup plus grande que stipulee anterieurement, diminuant les controles sur les taux de deplacement dans le systeme de chevauchement et le moment de la deformation regionale dans l'ouest de l'etat de Washington. De nouveaux âges plateaux 40 Ar/ 39 Ar de la phengite dans des roches volcaniques au facies des schistes bleus, aussi a Richardson, datent

Available biomagnetostratigraphy suggests that the Palaeocene interval in the classic Tethyan setting of the Bottaccione section (Gubbio, central Italy) may be condensed relative to other outcrops in the area and/or that the Bottaccione succession may contain an unidentified stratigraphic gap in the lower Palaeocene. However, new integrated stratigraphic data, including from bio-, magneto-, chemo-, and cyclostratigraphy, provide robust evidence that the Bottaccione section is complete and comparable to other successions cropping out in the Umbria–Marche area, which solves potential conflicts in the interpretation of the regional biostratigraphic and lithostratigraphic records. The recognition of orbitally forced sedimentary cycles, together with the availability of a carbon isotope profile, makes the Bottaccione outcrop a potential reference section for comparison with the already-available record of carbon-cycle alterations in the early–middle Palaeocene.

High-resolution micropalaeontological and chemostratigraphic records for the Hauterivian–Aptian succession outcropping at Calabianca (NW Sicily) provide new insight into the palaeoclimatic and palaeoceanographic evolution of the Tethys Ocean. Calcareous nannofossil and planktonic foraminiferal biostratigraphy together with δ13C chemostratigraphy allowed the identification of a hiatus in the Barremian and a major one including most of the Upper Aptian, the entire Lower Albian and part of the Middle Albian. The Livello Selli equivalent was identified on the basis of lithology and well constrained by calcareous plankton biostratigraphy as well as by the δ13C curve. The multi-proxy record from the Calabianca section is consistent with previous documentation of Tethyan sections, and others worldwide. Early Aptian global events, such as black shale deposition, nannoconid crisis, C isotopic negative spike and positive excursion associated with the OAE1a, increase in abundance of leupoldinids and clavate hedbergellids are superimposed on local/regional events, being strictly related to climate changes and increased run-off. Based on micropalaeontological results and geochemical proxies (Ba, P, V, Ni), the Livello Selli equivalent is interpreted as a high-productivity event associated with variable but overall anoxic/dysoxic conditions in the lower water column. The onset of new physical, chemical and biological conditions in the oceans and of the mid-Cretaceous greenhouse climate are interpreted as consequences of the superplume episode.

New findings of Early Cretaceous well-preserved planktonic foraminiferal assemblages from the Cismon core (NE Italy) and Calabianca section (NW Sicily) lead to a better understanding of the morphological features of several taxa. This paper deals with the revision of the taxa bearing radial chamber prolongations. Comparison of morphological characteristics between the genus Leupoldina Bolli, 1957 and Schackoina Thalmann, 1932 resulted in retaining Leupoldina as a valid genus that is distinguished from Schackoina by possessing radially elongate chambers ending with close, bulb-shaped extensions instead of open tubulospines. Moreover, the coiling mode in Leupoldina is pseudoplanispiral to trochospiral, whereas Schackoina is initially slightly trochospiral passing to planispiral, as supported by the asymmetry and symmetry of the aperture across the periphery, respectively. The species of the genus Leupoldina retained here are L. cabri Sigal, 1952, L. reicheli Bolli, 1957, and L. pustulans Bolli, 1957, among which three subspecies have been recognized on the basis of the number of chambers in the outer whorl; L. pustulans pustulans Bolli, 1957, L. pustulans quinquecamerata Bolli, 1957 and L. pustulans hexacamerata , subsp. nov. Stratigraphically, L. pustulans pustulans first appears in the Upper Barremian, L. cabri in the Lower Aptian just below the Selli Level, and the other taxa in the Upper Aptian above the Selli horizon. However, L. pustulans quinquecamerata and L. pustulans hexacamerata have ranges that are restricted to the lower part of the L. cabri Zone, whereas L. pustulans pustulans and L. reicheli range up to the base of the Globigerinelloides ferreolensis Zone.

Combining transcranial magnetic stimulation (TMS) and electroencephalography (EEG) constitutes a powerful tool to directly assess human cortical excitability and connectivity. TMS of the primary motor cortex elicits a sequence of TMS-evoked EEG potentials (TEPs). It is thought that inhibitory neurotransmission through GABA-A receptors (GABAAR) modulates early TEPs (

The two genera, Meridionalla El-Nakhal, 1982 and Costellagerina Petters, El-Nakhal and Cifelli, 1983, both erected to accommodate all the pre-Campanian meridionally costellate species, are discussed after comparison with the holotypes of the type species. Observations clearly indicate that Costellagerina is the appropriate genus, while the genus Meridionalla is inappropriate because its type species, Hedbergella murphyi Marianos and Zingula 1966 does not possess the textural ornamentation diagnostic for the genus.

An integrated stratigraphic study of the upper Paleocene to lower Eocene Scaglia limestones of the Contessa Road section has allowed us to identify the classical markers of the Paleocene-Eocene transition. The section provides a good magnetostratigraphic record as well as a continuous calcareous nannofossil and foraminiferal biostratigraphy. A negative Carbon Isotopic Excursion (CIE) occurs in the lower part of Chron C24r. The calibration to calcareous plankton zonation indicates that the CIE occurs in the lowermost part of calcareous nannofossil Zone NP 10 and the upper part of Zone CP8, that is in the planktonic foraminiferal Zone P5. In the same stratigraphic interval, a distjnct turnover in the calcareous benthic foraminifera and a sharp change in the Deep Water Agglutinated Foraminiferal (DWAF) assemhlages have been recognised. The record of DWAF, however, indicates a gradual initiation of such a change beginning some 150 k.y. before the CIE and BEE. ispartof: Bulletin de la Société Géologique de France vol:171 issue:3 pages:355-365 status: published

Pleistocene, or younger, mud diapirism is recorded along the arcuated crest of the Mediterranean Ridge Accretionary Complex over a distance of more than 450 km. The extruded mud-supported breccia, named mud breccia, is poorly fossiliferous, but the matrix may be dated as Late Aptian to Albian and Late Burdigalian to Langhian in age based on the calcareous plankton content. Calcareous nannofossils and planktonic foraminifera diagnostic of other ages are sparse within the two above-mentioned major assemblages. They indicate the presence of sediments attributable (1) to the Santonian and Cenomanian which occur in association with the mid-Cretaceous assemblages (Toronto, Unnamed, and Aros Domes), and (2) to the Serravallian which occur in association with the Late Burdigalian-Langhian assemblages in the Gelendzhik Dome. Aptian-Albian to Late Cretaceous sediments are pelagic in origin and are similar to the Scisti a Fucoidi and Scaglia Rossa Formations well known from continental Italy. Mixed dolomitic clasts and crystals also occur within the matrix, indicating the presence of portions of the evaporitic sequence of Messinian age in four cores from the western locations. Single, very rare plankton specimens, indicative of other ages different from those mentioned above, also occur within the matrix at various places. They are interpreted as reworked primarily within the Late Burdigalian-Langhian sediments. The age of the emplacement of the breccia should be older than the Middle Pleistocene as supported by the occurrence of clasts of this age in the mud breccia and is still an ongoing process at least in the Napoli Dome.

An expanded and largely complete upper Paleocene to upper Eocene section was recovered from the pelagic cap overlying Allison Guyot, Mid-Pacific Mountains at Ocean Drilling Program (ODP) Site 865 (18o26'N, 179o33'W; paleodepth 1300-1500 m). Reconstructions show that the site was within a few degrees of the equator during the Paleogene. Because no other Paleogene sections have been recovered in the Pacific Ocean at such a low latitude, Site 865 provides a unique record of equatorial Pacific paleoceanography. Detailed stable isotopic investigations were conducted on three planktonic foraminiferal taxa (species of Acarinina, Morozovella, and Subbotina). We studied benthic foraminiferal isotopes at much lower resolution on species of Cibicidoides and Lenticulina, Nuttallides truernpyi and Gavelinella beccariiformis, because of their exceptional rarity. The 5180 and 513C stratigraphies from Site 865 are generally similar to those derived from other Paleocene and Eocene sections. The planktonic foraminiferal records at Site 865, however, include significantly less short-term, single-sample variability than those from higher-latitude sites, indicating that this tropical, oligotrophic location had a comparatively stable water column structure with a deep mixed layer and less seasonal variability. Low-amplitude (0.1-0.8%o) oscillations on timescales of 250,000 to 300,000 years correlate between the/513C records of all planktonic taxa and may represent fluctuations in the mixing intensity of surface waters. Peak sea surface temperatures of 24o-25oC occurred in the earliest Eocene, followed by a rapid cooling of 3-6oC in the late early Eocene. Temperatures remained cool and stable through the middle Eocene. In the late Eocene, surface water temperatures decreased further. Vertical temperature gradients decreased dramatically in the late Paleocene and were relatively constant through much of the Eocene but increased markedly in the late Eocene. Intermediate waters warmed through the late Paleocene, reaching a maximum temperature of 10oC in the early Eocene. Cooling in the middle and late Eocene paralleled that of surface waters, with latest Eocene temperatures below 5oC. Extinction patterns of benthic foraminifera in the latest Paleocene were similar to those observed at other Pacific sites and were coeval with a short-term, very rapid negative excursion in/513C values in planktonic and benthic taxa as at other sites. During this excursion, benthic foraminiferal/5180 values decreased markedly, indicating warming of 4 to 6oC for tropical intermediate waters, while planktonic taxa show slight warming (1 oC) followed by 2oC of cooling. Convergence of/5180 values of planktonic and benthic foraminifera suggests that thermal gradients in the water column in this tropical location collapsed during the excursion. These data are consistent with the hypothesis that equatorial Pacific surface waters were a potential source of warm, higher salinity waters which filled portions of the deep ocean in the latest Paleocene. Oxygen isotopic data indicate that equator to high southern latitude sea surface thermal gradients decreased to as little as 4oC at the peak of the excursion, suggesting some fundamental change in global heat transport.

Objective Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system frequently affecting the corpus callosum, the largest interhemispheric fiber bundle, at an early stage of the disease. Here, we employed transcranial magnetic stimulation (TMS) combined with high-density 64-channel electroencephalography (EEG) to investigate cortical excitability and interhemispheric connectivity in 13 patients with early relapsing-remitting MS (RRMS) with mean EDSS 1 ± 1 compared to 16 age- and gender-matched healthy controls. Methods TMS was applied to the left and right M1 separately. Latencies and amplitudes of TMS-evoked EEG potential (TEP) components N45, N100, P180, N280 in the stimulated and non-stimulated hemisphere were analyzed using two different approaches: a cluster-based permutation analysis and an automated extraction of maximum and minimum values. Results Compared to healthy control subjects, RRMS patients did not show any significant differences in TEP latencies or amplitudes in the stimulated or non-stimulated hemisphere, neither for left nor for right M1 stimulation (all p > 0.05). Conclusion and key message We conclude that basic excitability and connectivity measures of TMS-EEG data are unaltered in early RRMS patients, which may indicate a high level of functional compensation for structural deficits in these patients, e.g. by activation of alternate routes of TEP propagation.

International audience; A new bio-chronostratigraphic framework is presented for the upper Campanian - Maastrichtian pelagic sediments of the Gubbio area (Bottaccione and Contessa Highway sections, Italy). New planktonic foraminiferal (FO of P. hantkeninoides), calcareous nannofossil (FO of M. prinsii, base acme of M. murus) and magnetostratigraphic data are provided and integrated to construct an age-depth curve based on the recent astronomical calibration of the late Campanian - Maastrichtian magnetic polarity time scale (Husson, D., Galbrun, B., Laskar, J., Hinnov, L. A., Thibault, N., Gardin, S., Locklair, R. E., 2011. Astronomical calibration of the Maastrichtian, Late Cretaceous. Earth and Planetary Science Letters 305, 328-340). All bio-horizons recorded in both sections fall on or are very close to the Line of Correlation (LOC), which testifies to the reliability of biochronologic studies in the Umbria-Marche basin. The proposed age model allows to estimate the sedimentation rates and the ages of calcareous nannofossil and planktonic foraminiferal bio-horizons in both sections. Also, it provides an excellent late Campanian - Maastrichtian reference for sections in the Umbria-Marche area and the entire Tethys. Due to the presence of a ∼425 kyr-long hiatus in Chron C31n of the Bottaccione section, the Contessa Highway section constitutes a more complete late Campanian - Maastrichtian reference for bio-magnetochronology in the Tethyan realm.

The study of planktonic foraminifera from the Lower Cretaceous succession along the Rio Argos (Caravaca, southern Spain) revealed that this group started to diversify much earlier than previously thought. Direct correlation with ammonites shows that, after the first diversification in the early Valanginian, planktonic foraminifera increased remarkably in abundance and number of species at the beginning of the Barremian. More than 10 species occur in the upper Barremian part of the section. The evolutionary appearance of several taxa is shown to have occurred earlier than previously recorded. In particular, the genus Globigerinelloides appeared in the late Valanginian ( G. gottisi ), with G. blowi and G. aptiense first occurring in the early late Barremian, when all Globigerinelloides registered an acme. Hedbergella similis, H. kuznetsovae , and the clavihedbergellids appeared in the early Barremian, followed by a new diversification in the early Aptian. Based on these observations, a new zonation is proposed.

The direct correlation between ammonites, calcareous nannofossils, planktonic foraminifera and magnetic chrons in the late Hauterivian-Barremian interval is reported here. Ammonites of this age were discovered in the Gorgo a Cerbara section (Umbria-Marche Apennines) where all fossil groups exceptionally occur together and, furthermore, the magnetic sequence is already known. This is, therefore, a reference section for the Lower Cretaceous of the Mediterranean domain. Correlation between biostratigraphic scales and magnetic chrons of the M-sequence is also based on data from other sections in the same domain. The Hauterivian-Barremian boundary falls within CM4 and the lower-upper Barremian boundary within CM3. At Gorgoa Cerbara the genus Globigerinelloides is first recorded only from the lowermost Barremian, although its appearance in other sections occurs in the upper Valanginian. The first occurrence of the nannofossil Rucinolithus irregularis occurs within the Martelites sarasini Zone, predating the lower boundary of the Aptian stage and the base of chron CM0.

The Barremian-Aptian boundary interval of the Gorgo Cerbara section (Marche, central Italy) was revisited in order to improve stratigraphic correlations and investigate plankton evolution. A very close sampling at cm scale was carried out in the upper Maiolica and basal Scisti a Fucoidi formations. The latter formation includes the Livello Selli, the landward sedimentary expression of oceanic anoxic subevent OAE la. The study of closely spaced samples revealed that (1) the first diversification among planktonic foraminifera, marked by the appearance of the genus Globigerinelloides , occurred during the Barremian (this event was dated by means of ammonites); thus the first occurrence (FO) of both Globigerinelloides duboisi and Globigerinelloides blowi cannot be used to identify the Aptian; (2) the appearance of Rucinolithus irregularis is the biostratigraphic event which best approximates the Barremian-Aptian boundary; and (3) chron M0, being slightly younger than the FO of R. irregularis , is very close to this boundary. Semiquantitative and quantitative analyses of planktonic foraminifera, calcareous nannofossils and radiolarians show that the three groups fluctuate in abundance and assemblage composition throughout the studied interval. An important change in plankton distribution patterns occurs within the G. blowi foraminiferal Zone and C. litterarius nannofossil Zone, where planktonic foraminifera, radiolarians and calcareous nannofossils start to show large-scale, higher frequency fluctuations in abundance; fluctuations in the three groups are out of phase. These new plankton distribution patterns are interrupted by the Livello Selli, which is preceded and followed by ‘critical intervals’. The distribution and composition of all three planktonic groups lead to the interpretation of the ‘critical intervals’ as representing increased nutrient contents in the surface water and the Livello Selli as a very high fertility event. Among planktonic foraminifers the hedbergellids seem to indicate a more eutrophic habitat than the globigerinelloids. In calcareous nannofossil assemblages, the abrupt crisis affecting the nannoconids prior to deposition of the Livello Selli suggests that these nannofossils are characteristic of more oligotrophic conditions, whereas Zygodiscus erectus is indicative of a more eutrophic environment. Based on our data, the early Aptian Livello Selli has the same oceanographic significance as the latest Cenomanian Livello Bonarelli, i.e., it represents a high fertility event on a global scale.

The Paleogene evolutionary records of planktonic foraminifera and larger benthic foraminifera show parallel patterns in development that may, in part, reflect changes in nutrient flux to surface waters. Following the terminal Cretaceous extinctions, faunas were dominated by a few cosmopolitan opportunistic species. More specialized k-strategists in both groups diversified during the Paleocene, dominating into the early Eocene, consistent with he globally mild climatic regime and probable limited rates of nutrient flux to surface waters. High-latitude cooling intensified in the middle Eocene, promoting diversification of less specialized taxa characteristic of cooler and deeper waters, higher latitudes, meridional upwelling zones, and boundary currents. Geographic ranges of warm-water taxa diminished and fragmented, yet many species survived. Thus, global diversities during the middle Eocene were the highest in the Cenozoic. As cooling and increased rates of nutrient flux further intensified in the late Eocene, extinction rates of warm-water planktonic and larger benthic species exceeded origination rates of cooler water and less specialized forms, so diversity dropped to intermediate levels where it remained through the late Eocene and Oligocene. Previous observations that planktonic foraminiferal faunas dominated by warm-water taxa are often replaced by cool-water faunas, even though oxygen isotopes only recorded relatively minor cooling, can be reconciled by the explanation that the biotic communities responded to changes in trophic resources and euphotic habitats that accompany the temperature reduction, as well as to temperature change itself.

Distribution patterns and morphologies of modern and Paleogene planktonic foraminifera in the Atlantic Ocean were compared. Although many Paleogene and modern planktonic foraminifera are homeomorphs, they are not ecomorphs. Morozovellid homeomorphs of the modern higher spired globorotaliids inhabited warmest layers of the mixed layer. The planorotalitids, homeomorphic with modern low trochospiral globorotaliids, have different geographic ranges; they predominated at temperature and higher latitudes where they grew to largest sizes. The cool water low-spired subbotinids little resemble the non-spinose, modern neogloboquadrinids which dominate polar faunas today. Spinosity of Paleogene polar forms indicates that they could have been carnivorous or omnivorous, rather than herbivorous like the modern neogloboquadrinids. Early Paleogene polar seas may have been relatively oligotrophic for at least part of the year. Some Paleogene genera may have been ecomorphic with their modern analogues. The dentoglobigerinids and globoquadrinids occupied equatorial and offshore upwellings much as Neogloboquadrina dutertrei does today. Because the globorotaloids and catapsydracids deposited calcitic crusts and register most enriched oxygen isotope values, they may have lived within and below the thermocline like some modern globorotaliids. Globorotaloids and catapsydracids may have been strictly herbivorous as are most modern, non-spinose species. Their predominance in later Paleogene lower latitude upwellings, but their near exclusion from polar regions indicates that subeuphotic equatorial waters may have been more eutrophic. Paleogene-type warming (in Zones P1d, P3a, P5, P6–7, late P12, late P16, late P19, and early P22) involves proliferation, evolutionary diversification, and poleward migration of thermophilic forms, but decreased species abundance at low latitudes, and diminished numbers of fertility indices (the guembelitrids, biserial heterohelicids, globigerinathekids, globoquadrinids, or dentoglobigerinids). Neogene-type warmings (in Zones P4 and probably P alpha and P21a) involved diversification of cooler water taxa, retreat of thermophilic forms from higher latitudes and their concentration in lower latitudes, and proliferation of fertility indices. Under these conditions oxygen isotope records include lower latitude warming, but cooling of temperature and higher latitudes and tropospheric waters. Planktonic foraminiferal diversity and population structure reflect changes in oceanic fertility and the depth of the thermocline. Cooling and eutrophication resulting in a contraction of the TRC (Trophic Resource Continuum) in Atlantic surface waters from late middle Eocene through mid Oligocene time explain the low diversities, extinctions of morphologically complex thermophilic species, increased dominance of opportunistic, subeuphotic, and temperature species, proliferation of euphotic and subeuphotic fertility indices, and geographic expansion of siliceous primary producers.

A relatively extended Oligocene pelagic sequence with good to medium recovery, drilled during DSDP Leg 77 in the Gulf of Mexico, yielded rich and well diversified planktonic foraminiferal faunas. Planktonic foraminifera recorded in Hole 538A span the interval from Zone P19 through P22. Evolutionary lineages were observed among the globoquadrinids, the globigernitids, and the “Globigerina” ciperoensis and Globigerinoides primordius groups. Quantitative analysis of planktonic foraminiferal assemblages shows that faunas fluctuate in abundance and species diversity throughout the sequence. A few of these fluctuations that could be related to selective dissolution are mainly confined to the early-mid Oligocene. A climatic curve was constructed using a warmer indicators, Turborotalia pseudoampliapertura, Globoquadrina tripartita, Dentoglobigerina globularis, Dentoglobigerina baroemoenensis, “Globigerina” ciperoensis and Globigerinoides groups, and Cassigerinella chipolensis; and as cooler indicators, Catapsydrax spp., Globorotaloides spp., Subbotina angiporoides group, Globigerina s. str., and the tenuitellids. Three major intervals are identifiable in the climatic curve: Interval 1 (lower) up to Zone P20 predominantly cooler; Interval 2 (intermediate) up to the upper part of Zone P21a with warm and cool fluctuations; and Interval 3 (upper), warmer, with large positive peak, due to abundant “G” angulisuturalis, at the beginning of Zone P21b with recooling midway in Zone P22. In intervals 1 and 2 planktonic foraminiferal faunas are dominated by temperate forms. Interpretation of planktonic foraminiferal data suggests that cooler water conditions characterize the early-mid Oligocene; during the mid Oligocene (most of Zone P21a) water masses exhibit peculiar characteristics transitional to the warmer waters prevailing during the late Oligocene. Warmer conditions were not definitely settled in Zone P22, however, as indicated by the cooler episode following the warmest peak. These climatic trends are inconsistent with those inferred from oxygen isotopes except at small scale. In fact, oxygen isotope values for Oligocene Atlantic Ocean are too heavy (thus too cool) in comparison with the high abundance and diversity of warm taxa, especially in Zone P22. When values are lighter (warmer), as in Zone P19, abundance and diversity of warm indices are too low. To explain such a cool isotope values in presence of highly diversified and abundant warm planktonic foraminifera, we suggest (1) that the oxygen isotope ratio used for estimating Oligocene paleotemperatures might be 1/%. heavier than Eocene values and further increased for the late Oligocene. This hypothesis implies the presence of a relatively extended ice cap in Antarctica in the early and mid Oligocene, and probably an increase in ice volume during the late Oligocene; (2) heavier isotope values might be related to an increase in salinity, or (3) by a combination of both ice cap and increase in salinity.

GABA(C) receptors play a role in myopia, memory-related disorders and circadian rhythms signifying a need to develop potent and selective agents for this class of receptors. Guanidino analogs related to glycine, beta-alanine and taurine were evaluated at human rho(1)GABA(C) receptors expressed in Xenopus oocytes using 2-electrode voltage clamp methods. Of the 12 analogs tested, 8 analogs were active as antagonists and the remaining were inactive. (S)-2-guanidinopropionic acid (IC(50) = 2.2 microM) and guanidinoacetic acid (IC(50) = 5.4 microM; K (B) = 7.75 microM [pK (B) = 5.11 +/- 0.06]) were the most potent being competitive antagonists at this receptor. In contrast, the beta-alanine and GABA guanidino analogs showed reduced activity, indicating the distance between the carboxyl carbon and terminal nitrogen of the guanidino group is critical for activity. Substituting the C2-position of guanidinoacetic acid with various alkyl groups reduced activity indicating that steric effects may impact on activity. The results of this study contribute to the structure-activity-relationship profile required in developing novel therapeutic agents.

Detailed planktonic foraminiferal biostratigraphy from eight measured sections of Cretaceous limestone near Laytonville, California, indicates a composite sequence that extends in age from late Albian to early Turonian. The sequence contains seven biozones and two subzones based on the first and last appearance datums of planktonic foraminifers examined in thin section. Unequivocal biostratigraphic facing directions show four sections are right side up and four are reversed, and confirm the stratigraphic polarity employed in the paleomagnetic studies of Alvarez et al. (1980) and Tarduno et al. (1986). Temporal changes in the microfauna deviate from the global trend. Early Albian through early Cenomanian planktonic foraminiferal assemblages dominated by opportunistic, eurytopic species of Hedbergella and Globigerinelloides give way in the late Cenomanian to assemblages containing more abundant larger, heavily ornamented stenotopic species of Rotalipora and Praeglobotruncana typical of stratified Tethyan oceans. Radiolarian replacement chert increases slightly in the late Albian to early Cenomanian part of the Laytonville sequence and then decreases in the late Cenomanian and early Turonian. Benthic foraminifers show a similar decrease in abundance and diversity. We propose that this complex of biogenic and lithogenic patterns records transit via oceanic plate motion from a depositional site in the southern part of the paleoequatorial zone of high productivity, characterized by pronounced upwelling and habitat destabilization, perhaps augmented by topographic upwelling, to the central part of the equatorial zone dominated by biogenic calcite deposition. Our model of northward transit from below the equator supports the paleomagnetic determinations of Alvarez et al. (1980) and Tarduno et al. (1986). Arrival at the paleoequator coincided with the onset of stratification in the world ocean during the middle Cenomanian, indicated by the diversification of the more complex rotaliporids, and the subsequent intensification of oxygen-depleted intermediate waters in the latest Cenomanian to early Turonian. Two pulses in heterohelicid abundance signify the onset or intensification of an oxygen-minimum layer if Cretaceous heterohelicids occupied habitats analagous to Tertiary biserial heterohelicids. The first pulse beginning in the middle Cenomanian Rotalipora reicheli Zone may indicate a minor expansion of the oxygen-minimum zone or regional upwelling due to transit of the site beneath the equatorial divergence. The second pulse in the late Cenomanian Dicarinella algeriana Subzone signals the onset of upwelling of deeper oceanic water masses that characterized the succeeding Whiteinella archaeocretacea Zone. Organic-rich black shales typical of the Whiteinella archaeocretacea Zone are missing at Laytonville, although samples do contain the low-diversity, partially dissolved, planktonic assemblages that characterize this zone. The lack of black shales suggests that deposition occurred at depths greater than the oxygen-depleted intermediate water depths or alternately indicates paleoceanographic conditions unique to the Pacific.

The study of planktonic foraminifera from the Lower Cretaceous succession at Angles (Southeastern France) directly correlated with ammonites, confirms that the origin of morphotypes with radially elongated chambers occur earlier than previously recorded. In particular, the species Hedbergella semielongata and Hedbergella roblesae bearing subclavate to clavate chambers first appear in the upper Hauterivian, just predating the onset of the oceanic anoxic Faraoni event. Based on these observations, a new zonation is proposed.

Objective To determine the physiology of short-interval intracortical inhibition (SICI) directly at the cortical level. Methods We recorded a 64 channel EEG during application of a magnetic test stimulus (TS100) 2 ms after a conditioning stimulus (CS70) over the left primary motor cortex at an intensity of 100% and 70% resting motor threshold for the right APB muscle, respectively. Subjects were given a single oral dose of diazepam or baclofen in this placebo controlled, pseudo-randomized, double-blinded crossover study. Results CS70 evoked clearly discernible and reproducible EEG potentials (TEPs) similar to TS100, i.e. a P25, N45, P70, N100, and P180 potential. In the paired-pulse condition, corrected for these CS70-induced TEPs, CS70 modulated all TS-evoked EEG potentials, i.e. suppressed the P25, N45, N100, and P180, whereas the P70 was increased. Preliminary analyses of the pharmacological data from eleven subjects further suggested an increase of SICI of the P25 potential by diazepam, in line with a GABAA-receptor mediated mechanism. Conclusions Our data provide evidence for the physiological mechanisms of SICI at the level of the human cortex with high temporal and spatial resolution. Key message SICI is characterized by temporally and spatially distinct modulation of TMS-evoked EEG responses.

1School of Earth, Ocean and Planetary Sciences, Cardiff University, Main Building, Park Place, Cardiff CF10 3YE, U.K. pearsonp@Cardiff.ac.uk 2Department of Geological Sciences, Rutgers University, New Brunswick, New Jersey 08903, U.S.A. 3Department of Paleobiology, MRC NHB 121, National Museum of Natural History, Smithsonian Institution, Washington, D.C., U.S.A. 4Institute und Museum fur Geologie und Palaontologie, Universitat Tubingen, D-72076, Germany 5Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, U.S.A. 6Laboratory Research Department, INA, NAFTAPLIN, HR/10000, Zagreb, Croatia 7Dipartimento Scienze della Terra, University of Milan, Via Mangiagalli 34, 20133 Milano, Italy

Our Neuchatel meeting of Lower Cretaceous ammonite workers was the last to be organized by Philip Hoedemaeker over a 15 year period. All members of the Kilian Group thank him for his contribution as chairman of: (1) the Lower Cretaceous Cephalopod Team (IGCP: International Geoscience Programme, projects 262: Digne, France, 1990; Mula, Spain, 1992, and 362: Piobbico, Italy, 1994; London, UK, 1997); (2) an independent group (Vienna, Austria, 2000); and (3) the IUGS (International Union of Geological Sciences) Lower Cretaceous Ammonite Working Group, the Kilian Group (Lyon, France, 2002).Progress in constructing the Lower Cretaceous standard ammonite zonation for the Mediterranean region can be followed by reading the successive reports. Fil: Reboulet, Stéphane. Universite´ Lyon 1; Francia Fil: Hoedemaeker, Philip J.. National Museum of Natural History; Países Bajos Fil: Aguirre-Urreta, Maria Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Alsen, Peter. Universidad de Copenhagen; Dinamarca Fil: Atrops, François. Universite´ Lyon 1; Francia Fil: Baraboshkin, Evgenij Y.. Moscow State University; Rusia Fil: Company, Miguel. Universidad de Granada, Facultad de Ciencias; España Fil: Delanoy, Gérard. Universite Nice; Francia Fil: Dutour, Yves. Universite´ Lyon 1; Francia Fil: Klein, Jaap. No especifica; Fil: Latil, Jean-Louis. No especifica; Fil: Lukeneder, Alexander. Naturhistorisches Museum, Vienna; Austria Fil: Mitta, Vasily. Paleontological Institute Of Russian Academy Of Sciences; Fil: Mourgues, Francisco A.. Observatoire Midi-pyrénées; Fil: Ploch, Izabela. Redakcja Serwisu Państwowego Instytutu Geologicznego; Fil: Raisossadat, Seyed Naser. University Of Birjand; Irán Fil: Ropolo, Pierre. Universite de Provence; Francia Fil: Sandoval, José. Universidad de Granada; España Fil: Tavera, José M.. Universidad de Granada; España Fil: Vasicek, Zdenek. Vsb – Technical University Of Ostrava; Fil: Vermeulen, Jean. No especifica; Fil: Arnaud, Hubert. Universite Grenoble Alpes; Fil: Granier, Bruno. Univ de Breragne Occidentale; Fil: Premoli-Silva, Isabella. Dipartimento Di Scienze Della Terra A. Desio

We present new stable (C, O) isotopic, biostratigraphic and organic geochemical data for the Vigla Shale Member of the Ionian Zone in NW Greece, in order to characterize organic carbon-rich strata that potentially record the impact of Cretaceous Oceanic Anoxic Events (OAEs). In a section exposed near Gotzikas (NW Epirus), we sampled a number of decimetre-thick, organic carbon-rich units enclosed within marly, locally silicified, Vigla Limestone (Berriasian-Turonian). All these units are characterized by largely comparable bulk geochemical characteristics, indicating a common marine origin and low thermal maturity. However, the stratigraphically highest of these black shales is further distinguished by its much higher total organic-carbon (TOC) content (28.9 wt%) and Hydrogen Index (HI) (529), and much enriched δ13Corg value (-22.1‰). Planktonic foraminiferal and calcareous nannofossil biostratigraphy indicate a lower to middle Albian age for the strata immediately above, and a lower Aptian age for the strata below, the uppermost black shale. In terms of molecular organic geochemistry, the latter black shale is also relatively enriched in specific isoprenoidal compounds (especially monocyclic isoprenoids), whose isotopic values are as high as - 15‰, indicating a substantial archaeal contribution to the organic matter. The striking similarities between the molecular signatures of the uppermost Vigla black shale and coeval organic-rich strata from SE France and the North Atlantic (ODP Site 1049C) indicate that this level constitutes a record of the Paquier Event (OAE 1b). © 2004 Cambridge University Press.

Palaeocene pelagic sequences cropping out in the Southern Alps are often characterized by a cyclic alternation of marly and calcareous lithologies. In particular, two sets of limestone–marlstone couplets are well exposed in the Ponte nelle Alpi and Tabiago sections, both Danian to Thanetian in age, located in the Belluno region (Venetian Prealps) and in the Brianza region (Central Prealps), respectively. A multidisciplinary approach was adopted to determine the nature of these alternations by analyzing for each semicouplet the abundance and composition of planktonic foraminiferal faunas, the degree of bioturbation and the carbonate content. Both sections show similar general features. The marly semicouplets of Ponte nelle Alpi and Tabiago sections are poor in planktonic foraminifera, but enriched in more tolerant (for nutrients and temperature) foraminiferal forms, and they record more oxygenated conditions. A possible interpretation of the lithological rhythms suggests that the marly semicouplets were deposited in periods of high seasonality. A marked seasonality, leading to an increased circulation of water masses, induced a nutrient enrichment in surface waters and oxygenated conditions at the seafloor. The data prove that the marly semicouplets represents fertile surface waters, whereas the calcareous ones record the opposite conditions: low seasonality, sluggish circulation and fewer nutrients at the sea surface. Spectral analysis was applied to evaluate the possible periodicities that could have driven the observed cyclicity. The periodicities recorded agree with those predicted by the palaeoclimatic Milankovitch theory for the precession, obliquity and eccentricity cycles. The stronger signal associated to obliquity has also been recorded during the mid-Cretaceous, confined to some intervals. This inconstancy is probably attributable to the response of the Earth to a signal that may only be detected in the low latitudes when climatic or oceanic conditions are particularly favorable to its transmission.

The mid-Cretaceous (Albian) deep-water sediments (coccolith–globigerinacean marls) of the Umbria–Marche Apennines show complex rhythmic bedding. We integrated earlier work with a time-series study of a digitized and image-processed photographic log of the Piobbico core. A drab facies is viewed as recording normal stratified conditions, and a red facies as the product of downwelling warm saline (halothermal) waters. Both are pervaded by orbital (Milankovitch) rhythms. These reflect fluctuations in the composition and abundance of the calcareous plankton in the upper waters. The drab facies is overprinted by redox oscillations on the bottom, including episodic precessional anaerobic pulses (PAPs). Contrasts between the individual beds representing the alternate phases of the precessional rhythm rose and fell with orbital eccentricity, in the classical pattern of Berger’s climatic precession or precession index curve, varyingly complicated by the obliquity rhythm. We conclude that greenhouse oceans in general, and perhaps this area in particular, were very sensitive to orbital forcing. Our count of 29 406-ky eccentricity cycles yields an Albian duration of 11.8 ± 0.4 My. Cyclostratigraphy: Approaches and Case Histories SEPM Special Publication No. 81, Copyright © 2004 SEPM (Society for Sedimentary Geology), ISBN 1-56576-108-1, p. 57–8

This volume is derived from an SEPM international workshop entitled Multidisciplinary Approach to Cyclostratigraphy, organized by the editors in May 2001 and held in Sorrento (Naples, Italy). In the Introduction we offer a brief history of how concepts of orbital cyclicity and its effects on the Earth evolved, an appraisal of the present state of research, and an overview of the papers in this volume. The main body of the volume consists of the contributed studies. These include a paper on conceptual and pragmatic approaches to stratification cycles by one of the pioneers of cyclostratigraphy, Walther Schwarzacher, who, in the 1940s, discovered the hierarchical expression of orbital cycles in rocks. The other contributions are specific studies of cyclic sequences, extending from the Quaternary back to the Triassic, covering the range from continental deposits to the deep sea, and employing a wide variety of techniques for extracting and processing the information.

The Paleocene-Eocene Thermal Maximum (PETM) has been attributed to a rapid rise in greenhouse gas levels. If so, warming should have occurred at all latitudes, although amplified toward the poles. Existing records reveal an increase in high-latitude sea surface temperatures (SSTs) (8° to 10°C) and in bottom water temperatures (4° to 5°C). To date, however, the character of the tropical SST response during this event remains unconstrained. Here we address this deficiency by using paired oxygen isotope and minor element (magnesium/calcium) ratios of planktonic foraminifera from a tropical Pacific core to estimate changes in SST. Using mixed-layer foraminifera, we found that the combined proxies imply a 4° to 5°C rise in Pacific SST during the PETM. These results would necessitate a rise in atmospheric pCO 2 to levels three to four times as high as those estimated for the late Paleocene.