Remmert Daams

A new chronology for the middle to late Miocene continental record in Spain

Abstract The first detailed chronology for the middle to late Miocene continental record in Spain is presented, based on high-resolution magnetostratigraphic data of mammal-bearing sections which were studied in several basins (Calatayud-Daroca, Teruel, Valles-Penedes, Duero and Jucar-Cabriel). Our results indicate that these sections compose an almost complete magnetostratigraphic succession from the lower Aragonian (MN4) to the middle Turolian (MN12). Seven successive Mammal Neogene (MN) zone boundaries are directly dated in these sections, which often contain faunas of two successive zones in superposition. The three oldest boundaries are dated in the Aragonian type area (Calatayud-Daroca Basin). The MN4/MN5 boundary (Vargas section) occurs in chron C5Cr(o) with a corresponding age of 17.26 ± 0.01 Ma, the MN5/MN6 boundary (Aragon section) in chron C5ACn(0.8), with an age of 13.75 ± 0.03 Ma, and the MN6/MN7–8 boundary (Aragon section) in the interval C5Ar.1n–C5Ar.3r with an age of 12.75 ± 0.25 Ma. The MN7–8/MN9 (Aragonian/Vallesian) boundary, occurring in chron C5r.1n at 11.1 Ma, and the MN9/MN10 boundary, in chron C4Ar.3r at 9.7 ± 0.1 Ma, are recorded in the Valles-Penedes Basin (Vallesian type area) and are supported by the results from the Duero Basin (Torremormojon section). In the Turolian type area (Teruel Basin), the MN10/MN11 (Vallesian/Turolian) boundary (La Gloria section) occurs in chron C4An(y) at 8.7 ± 0.1 Ma. Taking into account the pre-existing data from the Jucar-Cabriel Basin, the MN11/MN12 boundary (Cabriel Valley section) is recalibrated to C4n.1n, at an age of 7.5 ± 0.1 Ma.

Evolution of early-middle miocene rodent faunas in relation to long-term palaeoenvironmental changes

Abstract Cluster and principal components analyses have been applied to the composite sequence of 59 rodent assemblages from Ramblian to Lower Vallesian deposits in the Daroca-Calamocha area in the Calatayud-Teruel Basin (North Central Spain). The studied record is thought to represent the interval from the late Aquitanian to the end of the Serravallian (i.e. Early to Middle Miocene, from ca. 22-10.5 Ma ago). The quantitative results are interpreted by using individual rodent taxa as environmental indicators, and by extrapolating the predominant adaptive strategies of recent taxonomic groups, which also seem to form natural groups on a demographic scheme (French et al., 1975). A general warming trend starts in the Rambian (Early Miocene) and continues into the Middle Aragonisn (early Middle Miocene). The cooling in the Middle to Late Aragonian boundary interval is correlated to the middle Miocene cooling phase. Another cooling occurred around the Aragonian-Vallesian boundary (late Middle Miocene). We relate a major increase of aridity in the beginning of the Middle Aragonian (ca. 16.5 Ma) to the spread of low biomass vegetation due to intensification of the subtropical belt (Wolfe, 1985). A notable feature around the Early-Middle Aragonian boundary, indicating a major shift of climatic belts, is the reversal of the relationship between our relative temperature and humidity curves: before the reversal we find a positive correlation, after it a negative correlation. Around the Middle to Late Aragonian boundary humidity increased again, and a further increase of humidity is indicated by the earliest Vallesian faunas. Our data suggest that the nature of favoured adaptive strategy amongst rodents is related, in the end, to the degree of climatic humidity.

Magnetostratigraphic dating of the middle Miocene climate change in the continental deposits of the Aragonian type area in the Calatayud-Teruel basin (Central Spain)

The exceptionally dense mammalian faunal record of the Aragonian type area in Central Spain shows that an important climate change towards a cooler and more humid climate is recorded during the Neogene Mammal Zone MN 5 [1]. The magnetostratigraphic results from mammal-bearing middle Miocene continental sections in the Aragonian type area indicate that the onset of this climate change, at the MN 4/MN 5 boundary, occurs in the reversed chron C5ACr and has an age of 14.1 Ma, according to the geomagnetic polarity timescale (GPTS) of Cande and Kent [2]. This age is consistent with the age estimate of 14.1-14.05 Ma for the main increase in 6 ~SO in the marine record [3]. These independent observations of time-equivalent cooling in both continental and marine records confirm and accurately date a global cooling event in the middle Miocene. The age of 14.1 Ma for the MN 4/MN 5 boundary is significantly younger than previously recorded in continental timescales [4,5]. This results in a longer duration, by approximately 3 Myr, of the MN 4 zone, which is consistent with the many important faunal changes occurring in MN 4. Furthermore, the MN 5/MN 6 boundary occurs in chron C5ACn (13.8-13.9 Ma) and the MN 6/MN 7-8 boundary in the interval C5Ar.ln-C5Ar.3r (12.7-13.0 Ma).

THE EARLIEST MAMMAL OF THE EUROPEAN PALEOCENE: THE MULTITUBERCULATE HAININA

Abstract A new species of multituberculate mammal, Hainina pyrenaica n. sp. is described from Fontllonga-3 (Tremp Basin, Southern Pyrenees, Spain), correlated to the later part of chron C29r just above the K/T boundary. This taxon represents the earliest European Tertiary mammal recovered so far, and is related to other Hainina species from the European Paleocene. A revision of the species of Hainina allows recognition of a new species, H. vianeyae n. sp. from the Late Paleocene of Cernay (France). The genus is included in the family Kogaionidae Rãdulescu and Samson, 1996 from the Late Cretaceous of Romania on the basis of unique dental characters. The Kogaionidae had a peculiar masticatory system with a large, blade-like lower p4, similar to that of advanced Ptilodontoidea, but occluding against two small upper premolars, interpreted as P4 and P5, instead of a large upper P4. The endemic European Kogaionidae derive from an Early Cretaceous group with five premolars, and evolved during the Late Cretaceous and Paleocene. The genus Hainina represents a European multituberculate family that survived the K/T boundary mass extinction event.

A stratigraphical framework for Miocene (MN4-MN13) continental sediments of Central Spain

New bio- and magnetostratigraphic data from the Miocene continental sediments of Central Spain are used to update the existing stratigraphical framework. Our revised record is based on the study of more than two hundred mammal faunas, ranging from the Late Ramblian (ca 18 Ma) to the Late Turolian (ca 6 Ma).

The Ramblian and the Aragonian: Limits, Subdivision, Geographical and Temporal Extension

In this paper a historical review of the definition and subdivison of the Aragonian is given. Furthermore, the limits of the Ramblian and the Aragonian, and the temporal and geographic extension of both stages are discussed. The “cricetid vacuum” in the Lower Miocene of Spain is compared to that of France and central Europe.

A new Pliocene xerine sciurid (Rodentia) from Kossom Bougoudi, Chad

Abstract A very well preserved, incomplete, articulated skeleton with nearly complete skull and mandible of a terrestrial squirrel belonging to the genus Xerus was unearthed at the Pliocene site of Kossom Bougoudi in Chad. Xerus daamsi, sp. nov. is characterized by a narrow nasal associated with medium size. The phylogenetic position of the new species among African Sciuridae was determined using cladistic analysis of craniodental characters. It is most similar to extant Xerus rutilus and Xerus erythropus, currently found in Ethiopia and Chad, respectively. Cladistic analysis also supports the monophyly of the African members of the tribe Xerini, and a sister group relationship between X. daamsi and X. rutilus whose position within the Xerini is poorly supported. The North African genus Atlantoxerus is valid and distinct from Xerus, emphasizing the faunal differences between North African and sub-Saharan regions of the continent. The close affinities of Xerus daamsi with xerines which are currently living in northern savannas, more precisely in the Horn of Africa, suggests the presence of the Somali-Masai vegetation type in Chad by 5 Ma.

La migración de Hipparion en Europa: datos magnetoestratigráficos de la zona de Daroca (España).

La sucesion estratigrafica de Nombrevilla en la cuenca de Calatayud-Daroca (Cordillera Iberica) contiene uno de los mas ricos registros de macro y microvertebrados fosiles del transito Aragoniense/Vallesiense. El estudio magnetoestratigrafico de Nombrevilla aporta nuevos datos sobre la cronologia de la aparicion de Hipparion, un bioevento que define la base del piso Vallesiense. La correlacion con la escala de tiempo de polaridad geomagnetica esta basada en la identificacion de C5n, un cron de mas de 1 Myr de polaridad normal que es caracteristico del Mioceno superior. La localidad clasica Nombrevilla 1, que representa el registro mas antiguo de Hipparion, se correlaciona con el tercio inferior del cron C5n, y le corresponde una edad interpolada de 10.7-10.8 Ma. Este dato se corresponde muy bien con la datacion magnetoestratigrafica del mismo bioevento en Siwaliks (Pakistan) asi como las dataciones radiometricas 40Ar/39Ar en otras localidades de la region mediterranea. La localidad con macrovertebrados mas alta sin Hipparion en la serie de Nombrevilla es Nombrevilla 9, que se correlaciona aproximadamente con el cron C5r.1n (11.1 Ma). Este resultado no se corresponde exactamente con los resultados del Valles-Penedes, donde una edad muy similar se obtiene para la primera aparicion de Hipparion. Aparte, Nombrevilla 9 es particularmente significativa puesto que muestra una asociacion de microvertebrados correspondiente a la zona local H, que clasicamente se habia identificado con el Vallesiense inferior. Los nuevos datos senalan una diacronia de cerca de 300 kyr. entre el limite inferior de la zona H y la aparicion de Hipparion en Calatayud-Daroca. La correlacion de las localidades del Aragoniense superior Nombrevilla 2, 3 y4 es relativamente incierta, si bien es seguro que se encuentran en la parte superior del cron C5r, con una edad no menor que 11.6 Ma.

GEOLOGICAL CHARACTERIZATION OF FLUVIAL SEDIMENTS: Geological Modeling Project (GM2): Final report of the GEOSCIENCE Project JOUF-0036

ABSTRACT The Geological Modeling Project GM2 under the Joule I research program was initiated in 1990. Two consortia were formed, which concentrated on separate aspects of geological modeling. The TUD, CSIC, TNO consortium dealt with geological characterization of fluvial sediments as a tool for mathematical reservoir modeling, whereas the DALUC consortium developed interactive sequential forward-modeling software for the investigation and delineation of hanging-wall traps. The final reports of the DALUC Consortium is presented in Chapter 4.