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Carbon and Oxygen Isotope Stratigraphy of the Upper Maastrichtian, Zumaya, Spain: A Record of Oceanographic and Biologic Changes at the End of the Cretaceous Period
Abstract
Oxygen and carbon isotope analysis of Upper Maastrichtian and lowermost Danian pelagic limestones and marls from Zumaya, Spain indicates that several major isotopic excursions occurred both before and during the Cretaceous/Tertiary (K/T) boundary event. The isotopic excursion that occurs at the Cretaceous/Tertiary boundary has previously been interpreted by most workers in terms of biologic and oceanographic changes associated with an extraterrestrial impact. Data indicate that this excursion is not significantly different from several others that preceed it, suggesting that the boundary excursion is not a unique event. These excursions are interpreted as indicators of episodic warming events of several 100 000 years duration with associated decreases in upwelling and primary productivity. Their occurrence in the latest Cretaceous may reflect the transition from the equator-dominated ocean circulation of the Cretaceous to the polar water-dominated circulation of the Cenozoic. Inoceramid and ammonite macrofossil disappearances apparently coincide with two distinct negative isotopic excursions. This suggests that their extinction in this basin was associated with surface-water warming events and decreases in productivity before the K/T boundary event. -from Authors
... Geochemical studies revealed that significant negative ␦ 13 C and ␦ 18 O excursions are commonly observed across the Cretaceous/Paleogene (K/Pg) boundary in sections characterized by continuous deposition across this boundary (Perch-Nielsen, 1982;Mount et al., 1986;Molina et al., 2006). Perch-Nielsen (1982) investigated the carbon-isotope records from seven K/Pg boundary sections from different locations in the world (El Kef, Lattengebirge, Caravaca, Stevns, Biarritz, South Atlantic, DSDP site 524, and Pacific DSDP site 465 A). ...
... They noted a decrease of about 3‰ in ␦ 13 C values in the lowermost Paleogene sediments closely associated with the K/Pg boundary. This ␦ 13 C decline was interpreted as a perturbation of the carbon due to a major, global drop in plankton bioproductivity of sea-surface waters (Mount et al., 1986;Keller and Lindinger, 1989;Keller et al., 2007). The K/Pg mass extinction is responsible for the extinction of 75% of marine species and had a particularly profound impact on plankton communities (Thierstein, 1982;Fuqua et al., 2008). ...
... The ␦ 18 O excursions recorded around the K/Pg boundary probably represent increasing temperatures (Mount et al., 1986). Baum et al. (1994) attributed the variations in ␦ 18 O around the K/Pg boundary to eustatic sea-level changes. ...
Calcareous nannofossil data, δ¹³C and δ¹⁸O values, and carbonate contents of the uppermost Maastrichtian–lower Paleocene succession cropping out at the Misheiti section (East Central Sinai, Egypt) have been used to denote and reveal the changes across the Cretaceous/Paleogene (K/Pg) boundary. The study interval belongs to the uppermost Sudr Formation and the Dakhla Formation. Four calcareous nannofossil zones (Micula prinsii, NP1, NP2/3, and NP4) were recognized. The δ¹³C profile and the carbonate content show significant decreases across the K/Pg boundary. A hiatus at the K/Pg boundary is indicated by the absence of the basal part of Zone NP1. Geochemical results and calcareous nannofossil assemblages reflect fluctuations of the paleotemperature during the latest Maastrichtian–early Paleocene.
... This extreme and rapid lowering of global sealevel is acknowledged to have resulted in a significant shift from marine to non-marine depositional environments with a loss of epicontinental and coastal habitats ( Kauffman, 1979). Such a change, combined with an enormous flux of volcanic gases into the atmosphere ( Ekdale & Bromley, 1984) and great changes in oceanic circulation ( Mount et a/., 1986) were regarded as the primary causes for the major biological extinctions of the terminal Cretaceous ( Ekdale & Bromley, 1984, p. 698). Moreover, a major evolutionary re-organization of microbial communities brought about drastic changes in Tertiary sediments ( Monty, 1979). ...
... Such a change, combined with an enormous flux of volcanic gases into the atmosphere ( Ekdale & Bromley, 1984) and great changes in oceanic circulation ( Mount et a/., 1986) were regarded as the primary causes for the major biological extinctions of the terminal Cretaceous ( Ekdale & Bromley, 1984, p. 698). Moreover, a major evolutionary re-organization of microbial communities brought about drastic changes in Tertiary sediments ( Monty, 1979). The Pachino area affords the opportunity to document the disappearance of one of the latest known rudist-coral frameworks. ...
Maastrichtian strata from the Pachino area (SE Sicily) provide a model of association between rudist-coral frameworks and submarine volcanic activity. Two successive carbonate units are distinguished: (a) Coral-rudist bioherms and biostromes developed in a high-energy environment. (b) Hippuritid build-ups and banks overlain by rudist-coral clusters which grew under harsher ecological conditions, in a weaker current regime. At the top of the Maastrichtian sequence, the growth of rudist-coral frameworks ceased as ecological conditions shifted toward restricted environments. The inferred succession reflects a gradual decrease in current strengths and water depths, related to the Maastrichtian regressive phase. The frameworks display consistent evolutionary sequences reflecting progressive changes in their biota, structure, size and shape. Occurrences of rudist-coral frameworks are clearly linked with submarine volcanoes which provided opportunities for their development; they sometimes grew in the vicinity of active-vent centres, a feature reported for the first time in the Upper Cretaceous.
... There has been no agreement on the timing of the period in which these hypothetical warm deep waters existed: Mount et al. (1986) agreed with Barron et al. (1981) that the formation of warm, salty, deep waters might have ended during the late Maes trichtian. Data on Cerium anomalies of sediments from the Rio Grande Rise (Hu et al., 1988) suggest that better oxygenation of deep waters in the South Atlantic started in the early Eocene; Hay (1988) suggested that circulation was halothermal (warm, salty deep waters) through the Eocene, whereas Prentice and Matthews (1988) concluded that low-latitude production of deep water was important through most of the Tertiary. ...
Upper abyssal to lower bathyal benthic foraminifers from ODP Sites 689 and 690 on Maud Rise are reliable indicators of Maestrichtian through Neogene changes in the deep-water characteristics at high southern latitudes. Benthic foraminiferal faunas were divided into eight assemblages, with periods of faunal change at the early/late Maestrichtian boundary (69Ma), at the early/late Paleocene boundary (62Ma), in the latest Paleocene (57.5Ma), in the middle early Eocene to late early Eocene (55-52Ma), in the middle middle Eocene (46Ma), in the late Eocene (38.5Ma), and in the middle-late Miocene (14.9-11.5Ma). The highest diversities of the post-Paleocene occurred during the middle Eocene; from that time on the diversity decreased steadily at both sites. Data on faunal composition suggest that the waters bathing Maud Rise were well ventilated during the Maestrichtian through early Paleocene as well as during the latest Eocene through Recent. The waters appeared to be less well ventilated during the late Paleocene as well as the late middle through early late Eocene, with the least degree of ventilation during the latest Paleocene through early Eocene. -from Author
... An example of similar difficulties is the search for the last ammonoids in the terminal Cretaceous, a group that had been thought to have been extinct before the Big Bang at the Mesozoic-Cenozoic boundary. Meticulous investigations finally revealed the last ammonoid specimens ) very close to the anomalies that record the effects of the Chicxulub impact (e.g., Mount et al. 1986, Lamolda 1990). The long quasi-hidden existence of the ammonoids portrays the ordinary record of rare species and simulates a much shorter stratigraphic range (see also Machalski andHeinberg 2005 andMachalski 2005). ...
The Moroccan Atlas ranges provide sections that help reconstruct the earliest evolution of Paradoxides s.l. A fine-scale analysis of the basal part of the Jbel Wawrmast Formation in the eastern Anti-Atlas and comparisons with other sections in southern Morocco not only shows the abrupt appearance of Acadoparadoxides in nearly monofacial successions, but also illustrates a rapid diversification of the genus. This remarkable evolution of the clade includes material that can be assigned provisionally to the frequently described species Acadoparadoxides mureroensis (Sdzuy, 1958), to A. nobilis (Geyer, 1998) and also to the new species A. pampalius, A. levisettii and A. ovatopyge, of which A. pampalius can be shown to be the oldest described species of Paradoxides s.l. presently known. A fine-scale biostratigraphic and depositional development analysis permits a precise evaluation of suggested correlations within West Gondwana and into other Cambrian continents, and shows that attempts at precise correlations based on Acadoparadoxides species, and particularly A. mureroensis as a key taxon for global correlation, suffer from deficiencies that become obvious. In addition, the often subtle differences between species of the A. mureroensis clade illustrate that a confident identification of these species is only possible for well-preserved and largely undistorted specimens. Thus, many reports of A. mureroensis may be based, in part, on unfavourably preserved specimens of other species. The concept of a fairly variable species and even the idea of a dimorphism seem to have led to problematic identifications. In this context, material from the Taurus Mountains, southern Turkey, identified as A. mureroensis is identified herein as Acadoparadoxides deani n. sp. Paradoxides s.l. species appear to have been quite provincial in their palaeogeographic distribution, and an analysis of early appearing species shows that A. harlani (Green, 1834) was restricted to the Avalonia palaeocontinent, is incorrectly reported from West Gondwana and cannot be used as a basis for lower Series 3 correlation or chronostratigraphy. Finally, the so-called Valdemiedes Event described from the Iberian Chains in Spain obviously is a regional feature based on the abrupt appearance of an early, but not the earliest, Series 3 trilobite assemblage above a barren interval. This “event” appears to be a local stratigraphic artefact and does not reflect regional West Gondwanan or global geological history.
Kurzfassung
Die marokkanischen Atlas-Gebirge beinhalten Profile, welche die früheste Entwicklung der Sammelgattung Paradoxides illustrieren. Eine feinstratigraphische Analyse des basalen Abschnitts der Jbel-Wawrmast-Formation im östlichen Anti-Atlas und Vergleiche mit anderen Profilen im südlichen Marokko zeigen nicht nur das plötzliche Auftreten von Acadoparadoxides in nahezu monofaciellen Abfolgen, sondern auch eine rasche Diversifikation der Gattung. Diese bemerkenswerte Evolution wird auch durch Material belegt, das mit gewissen Einschränkungen zur häufig beschriebenen Art Acadoparadoxides mureroensis (Sdzuy, 1958) zu zählen ist, außerdem A. nobilis (Geyer, 1998), und die neuen Arten A. pampalius, A. levisettii und A. ovatopyge. Acadoparadoxides pampalius ist die älteste bisher beschriebene Art von Paradoxides s.l. Die hochauflösenden biostratigraphischen und ablagerungsgeschichtlichen Daten erlauben eine deutliche Präzisierung der bisher vorgeschlagenen Korrelationen innerhalb von West-Gondwana und zu anderen kambrischen Kontinenten. Dabei werden Defizite in der Genauigkeit derjenigen globalen Korrelationen deutlich, die sich bisher auf Acadoparadoxides und besonders A. mureroensis als Schlüsseltaxon stützten. Außerdem zeigen die oft geringfügigen morphologischen Unterschiede zwischen den Arten der mureroensis-Gruppe, dass eine sichere Identifikation solcher Arten nur bei gut erhaltenen und mehr oder weniger undeformierten Stücken möglich ist, so dass einzelne Nachweise von A. mureroensis unzulänglich erhaltene Stücke von anderen Arten darstellen können. Das Konzept einer sehr variable Art und darüberhinaus die Idee eines Dimorphismus können zu ungerechtfertigten Identifikationen von A. mureroensis geführt haben. In diesem Zusammenhang wird Material aus dem Taurus-Gebirge der südlichen Türkei, das als A. mureroensis bestimmt wurde, hier als Acadoparadoxides deani n. sp. abgetrennt. Das aus den Iberischen Ketten von Spanien beschriebene, so genannte Valdemiedes Event ist offenkundig eine regionale Erscheinung ohne Signifikanz und Bedeutung für kontinentale oder sogar subglobale Maßstäbe.
... In the last half of the 1980s, as more scientists look at the K-Pg boundary layer a third extinction pattern was suggestedstepwise mass extinctionin which different kinds of organisms disappear within different layers before the end of the Cretaceous and the layer containing the iridium (Mount et al., 1986;Keller, 1989). Correlated with this finding is the fact that in some localities, iridium is not restricted to the K-Pg boundary clay but appears to diminish gradually in concentration as one moves up or down from this layer (also termed "smeared anomalies"). ...
The state of geoscience education, in terms of numbers teachers, students taught, and perceived importance, has been lagging behind the other science disciplines for decades. Part of the reason for this is that geology is seen as a "derivative" science as compared to its "experimental" counterparts (for instance, physics and chemistry). However, with current global issues facing the populations of the world (climate change, scarcity of clean water, increasing fossil fuel usage), being geoscience literate is a must. We will show that, in fact, the geological sciences have their own philosophical structure, being both historical and hermeneutic, and it is the structure the makes the teaching of the geosciences for addressing such global issues advantageous. In addition, we will explore the use of historical controversies as a pedagogical tool for geoscience instruction. The history of geology is rife with controversy and the use of such a strategy has been shown to be effective for developing students' interest in the content, sharpening critical thinking skills, as well as emphasizing the nature of science. This chapter consolidates the knowledge base by describing the structure of the geosciences in terms of its philosophical, theoretical and cognitive frameworks. It highlights four geoscience controversies in terms of these frameworks, all the while reviewing the literature for the use of HPS in geoscience teaching. Finally it contains recommendations for possible future directions for geoscience education research within this context.
... " It might be added, however, that today most paleontologists accept the idea of impact as one of the extinction factors (along with marine regression, volcanic activity , and changes in climatic patterns), so the physical geologists and paleontologists have drawn closer together. In the last half of the 1980s, as more scientists looked at the K-Pg boundary layer, a third extinction pattern was suggested— stepwise mass extinction—in which different kinds of organisms disappear within different layers before the end of the Cretaceous and the iridium layer (Mount et al., 1986; Keller, 1989 ). Correlated with these fi ndings is the fact that in some localities, iridium is not restricted to the K-Pg clay layer but appears to diminish gradually in concentration as one moves up or down from this layer (also termed " smeared anomalies " ). Such evidence points to the possibility that multiple impacts were responsible for the extinction (Dingus and Rowe, 1998 ). ...
The state of geoscience education, in terms of numbers of teachers, students taught, and perceived importance, has been lagging behind the other science disciplines for decades. Part of the reason for this is that geology has commonly been seen as a “derivative” science, by educators, especially when compared to its “experimental” counterparts (for instance, physics and chemistry). However, with current global issues (climate change, scarcity of clean water, increasing fossil fuel usage) facing the populations of the world, being geoscience literate is a must. We show that, in fact, the geological sciences have their own philosophical structure, being both historical and hermeneutic, and it is this specifi c structure that aids students in addressing these global issues. In addition, we discuss the reasons for using historical controversies as a pedagogical tool for geoscience instruction. The history of geology is rife with scientific controversy, and the use of such a strategy has been shown to be effective for
developing students’ interest in the content, for sharpening critical-thinking skills, as well as for emphasizing the nature of science. This chapter consolidates the knowledge base by describing the structure of the geosciences in terms of its philosophical, theoretical, and cognitive frameworks. We fi nd that geoscience instruction could well be improved by incorporating history and philosophy of science and employing historical case studies, especially those involving controversy. Two well-known controversies, continental drift/plate tectonics and the Cretaceous-Paleogene extinction event, illustrate these frameworks.
Cretaceous transgressions left marine deposits over wide areas of Tethys, from which it is possible to develop paleogeographic maps depicting the configuration and extent of marine and continental paleoenvironments, including oceanic seafloor and structural patterns. Such maps can be used for testing the evolution of continent—ocean interactions and their climatic implications to increase understanding of the sedimentary products and processes related to them during the Cretaceous. The objectives of this chapter are to investigate the Cretaceous paleogeographic changes at stage or substage level when necessary, focusing on some key periods during which major changes occurred.
The Zumaya section (Northern Spain, Basque-Cantabrian basin) has become a reference section for the study of Cretaceous and Paleogene marine sediments. In order to analyze the paleoenvironmental evolution across the lower Paleogene, we carried out a quantitative study of early Paleogene (Cretaceous/Paleogene boundary) to early Eocene benthic foraminiferal assemblages in the Zumaya section. The relative abundance of the most representative calcareous and agglutinated taxa, as well as the diversity and heterogeneity of the assemblages, were calculated in 72 samples. Benthic foraminiferal assemblages indicate a depth of deposition of about 1000 m during the early Paleogene, and probably slightly shallower paleodepths during the late Danian. We suggest that, in addition to the paleodepth of deposition, other parameters (perturbation of the seafloor, turbidity currents, composition of the sediment) may have controlled the distribution and composition of the benthic assemblages. Hence, the abundance of Flysch-type agglutinated foraminifera (with organic cement) indicates a high flux of terrigenous, clastic material to the seafloor. This flux was particularly high during the Selandian and Thanetian. This study allowed us to analyze in detail several global events, such as the Cretaceous/Paleogene boundary event, the Mid-Paleocene Biotic Event, or the Paleocene-Eocene Thermal Maximum, where the most significant benthic foraminiferal turnover has been recorded. Benthic foraminifera were affected by the Cretaceous/Paleogene impact event: the drop in diversity of the assemblages and in the percentage of the species reflects variations in the trophic conditions after the boundary. Trophic conditions recovered during the Danian. Agglutinated opportunistic species proliferate during the Danian/Selandian boundary, although the relation of these changes with a possible global hyperthermal event remains to be confirmed. A decrease in the heterogeneity of the assemblages and an increase in oligotrophic and opportunistic species are recorded during the Mid-Paleocene Biotic Event. These assemblage changes are similar to but of lesser magnitude than those recorded during the Paleocene-Eocene Thermal Maximum, when the largest mass extinction of benthic foraminifera (both agglutinated and calcareous) of the Cenozoic is recorded. After the extinction event, we show the recovery of the assemblages during the early Eocene.
During a decade-long, real-time, historical study of the impact/volcanism/mass-extinction debates, a diversity of primary historical data, including tape-recorded interviews and opinion surveys on debated issues, has been acquired from hundreds of scientists representing the many disciplines engaged. I argue that the current extinction debates have impugned uniformitarianism, and will have further-reaching conceptual and philosophical effects than even those of the plate tectonics revolution, which strengthened, rather than detracted from, uniformitarianism. At the advent of the Alvarez-Berkeley group impact hypothesis of Cretaceous-Tertiary (K/T) boundary mass-extinction in 1980, the plate tectonics paradigm, which perfectly accommodated uniformitarianism, had already come to form the basis for well-received, endogenous mass-extinction and faunal-change hypotheses. For that reason especially did uniformitarianism contribute to a poor reception of the impact hypothesis, which flew in the face of uniformitarianism. Impact theory's reception was further chilled because it was based on evidence (iridium) unfamiliar to the community charged with its appraisal, its mechanism of extinction cause was improbable in terms of canonical knowledge, and it was authored by aliens to paleobiology (the discipline mainly charged with its assessment). Irrespective of the causal hypothesis chosen, that choice became the strongest predictor of how the chooser would select and apply standards in all aspects of the debates. Correlation also appeared-although less strong-between disciplinary specialty and choice of hypothesis and between disciplinary specialty and the assessment of evidence. Most paleontologists were straightaway against impact, and most paleontologists who later accepted boundary impact(s) continued to deny impact(s) as the main extinction cause. Many paleontologists regarded the duration, severity, and other aspects of the K/T mass extinction in terms of the fate of their own fossil groups. Vertebrate paleontologists were almost unanimously opposed to impact-as-extinction-cause; in contrast, micropaleontologists-especially those treating planktonic calcareous forms-were most often favorably inclined. Almost all specialists intimately familiar with impacting and earth-crossing bodies were sympathetic to all of impact theory. All volcanologists I interviewed rejected the volcanist hypothesis. Authors and published supporters of endogenous alternatives to the impact hypothesis, in all cases examined save one, were opposed to the impact hypothesis. However poorly informed, scientists seldom failed to subscribe to one of the extinction hypotheses. The mind-sets (gestalts) of opposed polemicists seemingly precluded agreement on any of the important debated issues. Impactors (advocates of impact-as-extinction-cause) and volcanists (proponents of volcanism-as-extinction-cause) commonly used different standards of appraisal and weighted the same evidence differently. Collaborative teams-with members often from distant, isolated disciplines but almost always supporters of the same mass-extinction hypothesis-formed overnight, with many members redirecting their careers in order to participate. Impact's opponents sought to demonstrate a lack of the ubiquitous, globally uniform effects claimed for an impact. It is shown here that a perceived or claimed anomaly (stair-step extinctions), in terms of one theory (single-impact), can grow into a standard of appraisal that can force the revision of the challenged theory (single impact) into an accommodating theory (multiple impacts). The search for impact sites and the remapping and dating of great flood basalt bodies are being actively pursued. The successful application of new methods, techniques, and instruments across a diverse and growing research front has facilitated the formulation of increasingly sophisticated models of the effects of impacts, mantle plumes, and other processes on sublithospheric, crustal, and bio-spheric processes, but other important likely effects of impacting and explosive vol-canism are yet to be modeled. The intensity, fast pace, and disciplinary scope of this continuing upheaval are providing extraordinary views of the workings of science.
Well exposed and stratigraphically well constrained by numerous studies, the Zumaia section is one of the best places to conduct
studies on the Palaeocene in basin facies. Thus, this section has been chosen [Schmitz et al., 2011] as a stratotype of Selandian basal and terminal limits (GSSP: Global boundary Stratotype Section and Point). The sediments
consist of carbonate hemipelagites interbedded with fine carbonate (Maastrichtian to Selandian) and siliciclastic (Thanetian
to Eocene) turbidites.
The purpose of this work is to geochemically characterize the Selandian by trace element contents (strontium and manganese)
and to try to assess the chemical composition of seawater during the Paleocene. Analysis of various separated granulometric
fine fractions show that hemipelagic sediments from the Zumaia section present a high preservation quality of the original
records of trace-element contents. Late burial diagenesis plays only a minor role and geochemical breaks are not reducible
to a change in the nature of carbonate producers.
The strontium contents of Paleocene sediments require that the Sr/Ca ratio of seawater was lower than that in the present
ocean. The Selandian is characterized by a positive excursion of the strontium curve. This accident is also recognized in
several worldwide sections and is related to the platform/basin carbonate sedimentation budget and the intensity of oceanic
hydrothermalism.
The Mn content of hemipelagites is very high and can reach 2500–3000 ppm in the Paleocene. A comparison of analyses by atomic
absorption spectrometry (AAS) and electron paramagnetic resonance (EPR) shows that both Mn2+ (in the calcite lattice) and Mn4+ (as oxide micro nodules) coexist. The Mn content fluctuations are related to the opening phases of the North Atlantic during
the Paleocene by submarine volcanism and hydrothermalism in the North Atlantic Igneous Province (NAIP).
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