Villa franchium
The Villafranchium is a regional land mammal stage in the terrestrial Neogene of Europe ( Piacenzian , Gelasian and Calabrian - Upper Pliocene and Lower Pleistocene ). It corresponds roughly to the period 3.5 to 0.9 million years BP . Characteristic for the stage are several drastic changes in fauna and the associated radiative spreading movements.
History and type locality
The term villa franchium was first used scientifically in 1865 by Lorenzo Pareto . He labeled this term fossil finds , which he in lake sediments in the northern Apennines in Villafranca d'Asti in the Italian Piedmont had made. He later extended the term to include mammals found in the Arno Valley in Tuscany . Since then, the term villa franchium has mainly been used by Italian, French and Swiss geologists, but unfortunately the term is often used somewhat imprecisely. Strictly speaking, the Villafranchium is characterized by the proboscid fauna communities associated with large Bovidae , Cervidae and Equidae .
Originally it was assumed that the Villa Franchium corresponds to the Upper Pliocene. In 1916 , for example, Maurice Gignoux equated the villa franchium with his newly created Calabrium . In 1948 an agreement was reached at the International Geological Congress to place the Calabrium (and with it the Villafranchium) at the base of the Pleistocene. It was not until 1963 that it was recognized that the fauna communities of the Villa Franchium are composed of a very heterogeneous composition and that they also take up a large part of the Pliocene and Pleistocene. Due to its rather long duration, Augusto Azzaroli divided the Villafranchium into six fauna levels in 1977, some of which can be defined by significant evolutionary upheavals.
stratigraphy
The faunal levels of the villa franchium follow the faunal communities of the preceding Ruscinium . In turn, they will be replaced by the faunal communities of the gallery . In contrast to the villa franchium, whose taxa are all extinct, the gallery already contains elements of fauna that are still present today.
The villa franchium extends over land mammal zones MN 16 , MN 17 and the lowest section of MN Q 1 .
The villa franchium is structured as follows (from young to old):
- Upper villa franchium
- Faunal communities of the outgoing villa franchise
- Tasso Fauna Community
- Olivola Fauna Community
- Middle villa franchium
- Lower villa franchium
Age and time equivalents
The Triversa Faunal Community can indirectly be assigned an age of around 3.5 million years BP as the basis of the villa franchium. The Triversa faunal community interlocks laterally in littoral sediments, which document the datable transition of the Foraminiferentaxa Globorotalia puncticulata - Globorotalia crassaformis .
Relatively strong scattering absolute ages were determined for equivalent French fauna communities. The Vialette and Les Etouaires sites showed ages between 3.3 and 2.6 million years BP.
The type locality in Villafranca d'Asti for its part yielded a paleomagnetically determined age of 3.05 to 3.01 million years BP.
The fauna communities of the youngest villa franchise have been dated around 0.9 to 1.0 million years BP in the vicinity of Rome . You can find them here at the upper end of the Calabrium below the striking Cassium erosion horizon . Comparable fauna communities in the Danube region are located directly below the Jaramillo polarity reversal and are therefore 1.07 million years old. The Villafranchium therefore covers the period 3.5 to 1.0 million years BP, ie Piacenzian to Upper Calabrian.
Lower villa franchium
Triversa Fauna Community
The transition from the Ruscinium to the Triversa fauna community of the Lower Villafranchium - also known as the Leptobos event - took place with drastic faunistic changes. For example, the antelope taxa Alephis and Parabos have been superseded by the evolutionarily advanced species Leptobos . With the exception of Croizetoceros ramosus, the Cervidae of the Ruscinium were small-stature forms. In the beginning of the villa franchium, the cervid fauna increased in biodiversity, and more developed, larger forms such as Cervus pardinensis , Cervus perrieri and Arvernoceros ardei appeared . Croizetoceros ramosus survived into the Villafranchium and was able to develop further developed subspecies. In the Perissodactyla , the massive Stephanorhinus megarhinus was replaced by the slimmer Stephanorhinus miguelcrusafonti and Stephanorhinus jeanvireti . Among the Canidae , Nyctereutes donnezani from the Ruscinium was followed by the taxon Nyctereutes megamastoides .
Large carnivores appeared for the first time, including Acinonyx , Chasmaporthetes , Homotherium and Megantereon . Ursus minimus probably emerged from Ursus ruscinensis . Lepus also appeared for the first time in Europe.
Apparently the proboscis did not suffer any major changes; they still show the same taxa Anancus arvernensis and Mammut borsoni . The same is true for Tapirus , which continued to exist. The population of Hipparion declined sharply in France and the species died out completely in Italy. Pliotragus first appeared among the ruminants .
The immigration of so many new taxa suggests a climatic change . The occurrence of Acinonyx and Pliotragus indicates that the forest vegetation is receding. Nevertheless, as in the previous Ruscinium, the temperatures remained warm. However, a significant interim deterioration should occur in the period 3.2 to 3.1 million years BP.
In addition to the type locality, sites belonging to the Triversa Fauna Community include Layna and Villaroya in northern Spain and Les Etouaires and Vialette in France.
Montopoli Fauna Community
The Montopoli Fauna Community started with a sharp turning point, the elephant equus event . Noteworthy new releases were the primitive elephant Archidiskodon gromovi , the large, monodactyl equine Equus livenzovensis , closely related to Equus stenonis and the American taxon Equus simplicidens , as well as the cervid Eucladoceros . Typical forest inhabitants such as mammoth , tapirus , sus minor and ursus minimus disappeared.
The newly released taxa speak for an open park landscape or savannah .
Age determinations for the Montopoli faunal community and their equivalents are close to the Gauss - Matuyama polarity reversal and result in BP in about 2.6 to 2.5 million years.
In addition to the type locality Montopoli in the lower Arno Valley, the Montopoli fauna community includes the Rincón in Spain, Roca Neyra in the French Massif Central , Tegelen in the Netherlands and Red Crag near Walton-on-the-Naze in England .
Middle villa franchium
The transition to the Middle Villafranchium took place without any major incisions, the taxa that appear are very similar to their predecessors, but show more derived characteristics.
Saint-Vallier Faunal Community
In the case of the proboscis, Mammuthus gromovi was followed by a taxon closely related to Mammuthus meridionalis with similar teeth but a much more primitive skull structure. Cervus pardinensis gave way to Cervus rhenanus (or Cervus philisi ), Croizetoceros ramosus ramosus was replaced in France by Croizetoceros ramosus medius and Croizetocerus ramosus minor and in Spain by Croizetoceros pueblensis . Cervus perrieri and Arvernoceros ardei no longer appeared. Eucladoceros tegulensis may have emerged from the more primitive Eucladoceros falconeri . Stephanorhinus jeanvireti has been replaced by the smaller taxon Stephanorhinus etruscus . Newly immigrated taxa are rarely found in the Saint-Vallier Fauna Community , including predominantly bovids such as Gallogoral meneghinii and Gazellospira torticornis as well as the medium-sized Felid Viretailurus schaubi .
In addition to the type locality of Saint-Vallier in the Département Drôme with its hardened loess deposits, the Saint-Vallier faunal community includes the sites of Chilhac , La Roche-Lambert , Le Coupet , Saint-Vidal and Senèze (all in the Massif Central ) and La Puebla de Valverde in Spain .
Absolute age dating has shown that the Chilhac site is at least 1.9 million years old BP. and around 2 million years BP for the Senèze site.
Tegelen Fauna Community
The Tegelen Fauna Community consists of the following taxa: Anancus arvernensis , Mammuthus meridionalis , Tapirus arvernensis , Stephanorhinus etruscus , Equus bressanus , Leptobos sp. , Eucladoceros ctenoides , Cervus rhenanus , Sus strozzii , Ursus etruscus , Enhydrictis Ardea , Pannonictis pliocaenica , pachycrocuta perrieri , Panthera gombaszogensis , Castor fiber , Trogontherium boisviletti , Mimomys pliocaenicus , Mimomys newtoni and Macaca sylvana florentina .
In the San Giacomo site near Anagni there are also Croizetoceros ramosus , Gazella borbonica , Equus stenonis and Mammuthus meridionalis .
The climatic conditions were moderate at the beginning of the Tegelen Faunal Community, but then deteriorated (cooling down). In the final section there were multiple oscillations from moderate to cool.
For the Tegelen fauna community, which is equivalent to the Tiglium , Zagwijn determined a period of 2.2 to 1.7 million years.
Upper villa franchium
The transition to the Upper Villafranchium is again marked by a striking, faunistic incision, the so-called wolf event .
Olivola Fauna Community
With the Olivola Fauna Community , named after the Olivola site in northwestern Tuscany, Nyctereutes , Gazella , Leptobos stenometopon , Cervus rhenanus and Eucladoceros tegulensis disappeared . At the same time, the wolf ( Canis etruscus ), but also Pachycrocuta brevirostris , Panthera toscana and Leptobos etruscus spread massively in Europe . Eucladoceros dicranios and Dama nestii were very likely evolutionary new forms. The elephants were represented by Mammuthus meridionalis meridionalis . The taxon anancus was also still present, but disappeared in the course of the Upper Villa Franchium.
The Wolf event has been linked to the upper limit of the Olduvai polarity zone and is therefore believed to have occurred about 1.77 million years ago BP.
Tasso Fauna Community
The overlying Tasso faunal community of the upper Arno valley consists of the same faunal elements as the Olivola faunal community with the exception of Anancus . A new addition was Canis arnensis (a primitive Coyote ), Canis falconeri , Hippopotamus antiquus (a relative of the African Hippopotamus gorgops ) Leptobos vallisarni (a close relative of the bison , but with slender limbs), Equus stehlini (probably a descendant of the much larger Equus stenonis ) and possibly Mimomys savini . Eucladoceros was stocky and Dama had peculiar characteristics.
Fauna community of the outgoing villa franchise
The faunal community of the outgoing villa franchise , occasionally also Farneta faunal community , includes the sites Creux de Peyrolles , Domegliara , East Runton , Farneta , Imola , Mugello , Pirro Nord , Scopitto , Selvella , and Senèze.
Their somewhat incompletely documented composition can be outlined as follows: The southern elephant Mammuthus meridionalis developed various subspecies such as M. m. cromeriensis in England, M. m. tamanensis in southern Russia and M. m. vestinus in Italy. These very large shapes were possibly evolutionary dead ends. Eucladoceros also formed large forms ( Eucladoceros dicranios and Eucladoceros tetraceros ). There were also Leptobos etruscus , Leptobos vallisarnis , Cervalces gallicus and Equus bressanus , also a large form and forerunner of Equus süssenbornensis .
The fauna community of the outgoing villa franchise is between 0.8 and 1.0 million years old BP.
Individual evidence
- ↑ L. Pareto: Note on the subdivisions que l'on pourrait établir dans les Terrains tertiaires de l'Apennin septentrional . In: Bull. Soc. Geol. Fr . tape 22 , 1865, p. 210-277 .
- ^ M. Gignoux: L'étage Calabrien (Pliocene superieur marin) sur le versant NE de l'Apennin, entre le Monte Gargano et Plaisance . In: Bull. Soc. Geol. Fr. Band 4 , no. 14 , 1916, pp. 324-348 .
- ↑ A. Azzaroli: Rinoceronti Pliocenici del Valdarno Inferiore . In: Palaeontogr. Ital. tape 57 , 1963, pp. 11-20 .
- ^ A b A. Azzaroli: The Villafranchian stage in Italy and the Plio-Pleistocene Boundary . In: G. Geol. Volume 41 , 1977, pp. 61-79 .
- ^ R. Sprovieri: Pliocene-early Pleistocene Astronomically forced planktonic foraminifera abundance fluctuations and chronology of Mediterranean calcareous plankton bio-events . In: Riv. It. Paleont. Strat. Band 99 , 1993, pp. 371-414 .
- ^ J. Couthures, JF Pastre: Contribution a la chronostratigraphie du Villafranchien: l 'Auvergne et le Velay (France). Our series of references from Plio-Pleistocene européen . In: Colloq. Le Villa Franchises méditerranéen . Lille 1983, p. 179-185 .
- ^ EH Lindsay, ND Opdyke, NM Johnson: Pliocene dispersal of horse Equus and late Cenozoic mammalian dispersal events . In: Nature . tape 287 , 1980, pp. 135-138 .
- ↑ PL Ambrosetti, A. Azzaroli, FP Bonadonna, M. Follieri: A scheme of Pleistocene chronology for the Tyrrenian side of Central Italy . In: BoIl. Soc. Geol. Ital. tape 91 , 1972, p. 169-184 .
- ^ GJ Kukla: Pleistocene land-sea correlations. I. Europe. In: Earth-Sci. Rev. Band 13 , 1977, pp. 307-374 .
- ↑ E. Heintz: Les populations de Croizetoceros ramosus (Cervidae, Mammalia) dans le temps et dans l'espace. In: Bull. Soc. Geol. Fr. Band 16 , 1974, p. 411-417 .
- ↑ G. Leone: Paleoclimatology of the Casas del Rincon Villafranchian series (Spain) from stable isotope data . In: Palaeogeogr., Palaeoclimatol., Palaeoecol. tape 49 , 1985, pp. 61-77 .
- ↑ J. Viret: Le loess à bancs durcis de Saint-Vallier (Drome) et sa faune de mammifères villa fran chiens . In: Arch. Mus. Hist. Nat. Lyon . tape 4 , 1954, pp. 1-197 .
- ^ O. Boeuf: Le site villafranchien de Chilhac (Haute-Loire), France. Étude paleontologique et biochronologique . In: Thesis. Univ. Paris VII . 1983, p. 253 .
- ↑ N. Thouveny, E. Bonifay: New chronological data on European Plio-Pleistocene faunas and hominid occupation sites . In: Nature . tape 308 , 1984, pp. 355-358 .
- ↑ M. Freudenthal, T. Meijer, AJ Van der Meulen: Preliminary report on a field campaign in the continental Pleistocene of Tegelen (The Netherlands) . In: Scr. Geol. Band 34 , 1976, pp. 27 .
- ↑ Biddittu, et al. a .: Anagni, a K-Ar dated Lower and Middle Pleistocene site, Central Italy: Preliminary Report . In: Quaternaria . tape 21 , 1979, pp. 53-71 .
- ^ WH Zagwijn: The Pliocene-Pleistocene boundary in western and southern Europe . In: Boreas . tape 3 , 1974, p. 75-97 .
- ^ C. De Giuli, F. Masini: Late Villafranchian faunas of Italy: the Casa Frata local fauna (Upper Valdarno, Tuscany) . In: Palaeontogr. Ital. tape 74 , 1987, pp. 1-9 .