Geomorphology and tectonics of uplifted coasts: New chronostratigraphical constraints for the Quaternary evolution of Tyrrhenian North Calabria (southern Italy)

The Middle and Late Pleistocene mammalian faunas of Japan are described with new opinions on their succession and relation to the continental faunas. Although fossil materials assignable to early Middle Pleistocene are seemingly scarce in Japan, the fauna of that time is considered to have been transitional between the Early and Middle Pleistocene ones. On the other hand, fossil records which are younger than early Middle Pleistocene are abundant from the mainlands of Japan; viz. the Honshu-Shikoku-Kyushu area.In the middle Middle Pleistocene, the fauna of this area contained a considerable number of taxa which are extant today in the area (about 50%). It was also characterized by a high proportion of endemic species and the predominance of temperate forest elements. From this time to the late Middle Pleistocene, several species disappeared from the fauna; at the same time, immigrants from the continent were scarce. The faunal characters of the late Middle Pleistocene were basically identical with those of the preceding time.In the early Late Pleistocene, no mammal seems to have immigrated from the neighboring continent, and faunal composition was almost consistent with that of the late Middle Pleistocene. The elements of that fauna still persisted in the late Late Pleistocene, apart from the extinction of a few forms. In addition to the fact mentioned above, immigration from the northern part of the continent was recognized in the late Late Pleistocene, although it was restricted to a few large herbivore forms and to a short time duration.The introduction of the continental faunas to the mainlands of Japan during Middle and Late Pleistocene times was not so remarkable as previously inferred. Therefore it becomes doubtful that the faunas of the area were drastically replaced by the immigration of the Choukoutien, Wanhsien and Loess faunas of China during those times.

An Anvilian (early pleistocene) marine fauna from western Seward Peninsula, Alaska

The Boiano Basin is one of the largest Quaternary intermontane basins of the central‐southern Apennines within one of the most tectonically active areas of the Mediterranean region. In order to reconstruct its entire Quaternary stratigraphic, tectonic, and palaeoenvironment evolution, lithofacies and palaeomagnetic analyses have been performed on a 900 m‐deep borehole (CP1) drilled in the southwestern sector of the basin. The Quaternary succession consists of an alternating of alluvial fan and fluvial–marshy deposits for a total thickness of 240 m, unconformably laying on Lower Miocene deposits of the Sannio Unit, thrusted on upper Miocene deposits of the Molise Flysch. In addition, the stratigraphic study and facies distribution of 29 intermediate and shallow wells drilled in the basin, allowing us to define the thickness and lithofacies variations of the Quaternary sedimentary units inside the entire Boiano Basin in the sector of Campochiaro alluvial fan. Our results demonstrate that the Boiano Basin infilling started during the late Early Pleistocene (c. 1.1 Ma) and developed with variation in lithofacies distribution and thickness. The first depositional unit (Early Pleistocene–early Middle Pleistocene in age) was palustrine and fluvial–marshy, the second (Middle Pleistocene in age) was characterized by the occurrence of the first cycle of alluvial fan deposition, the third (late Middle Pleistocene in age) was newly palustrine and fluvial marshy and, finally, the fourth recorded two cycles of alluvial fan deposition (late Middle Pleistocene and Late Pleistocene in age, respectively), interspersed by short periods of palustrinity, tephra layers deposition, and palaeosols development. The study allows the hypothesizing that the Quaternary infilling was accommodated within a graben (or semigraben) structure, affected mainly by extensional fault systems localized in the inner part of the basin and secondly by fault systems bounding the basin.

The current study focuses on the emblematic Myopus/Lemmus species complex (tribe Lemmini) in the European Pleistocene fossil record. The members of the two genera occupy distinct ecological niches and have different external appearances, but they are remarkably similar in their dental morphology, so that they were commonly thought of as undistinguishable in the fossil record. Thus, more or less all European Lemmini fossils have been assigned to the genus Lemmus. In the Early Pleistocene site of Schernfeld (Germany), the species Lemmus kowalskii had been described. It was thought by some authors that all Lemmini from Early to late Middle Pleistocene belong to this species.In the current study, we investigated Lemmini molar morphology from Western and Central European sites including Schernfeld (Early Pleistocene), Sackdillinger Höhle (Sackdilling Cave), and Koněprusy C718 (both early Middle Pleistocene), as well as other fossil localities with fewer specimens, formerly assigned to Lemmus kowalskii. Using an extensive modern referential material of Lemmus and Myopus, this study proposes to re-evaluate taxonomic status of the Middle and Early Pleistocene Lemmini. This modern referential also allows a better understanding of the morphology of Lemmus kowalskii specimens and its variability.Our results highlight the very high variation within fossil populations, as well as significant statistical differences between populations of the Early and Middle Pleistocene localities. A large part of these fossil specimens is firmly identified as Myopus sp., including the L. kowalskii holotype. Our identifications demonstrate that in most Early and Middle Pleistocene sites considered in this study, both genera (Lemmus and Myopus) are present. Possible interpretations and consequences for current view of lemming history are discussed, as well as some of the paleoecological and paleoenvironmental implications.

A reappraisal of the Early to Middle Pleistocene Italian Bovidae

The Pleistocene Fanglomerate Group of the southern part of Cyprus exemplifies coarse alluvial clastic deposition within a zone of focused tectonic uplift, related to collision of African and Eurasian plates, as documented by Ocean Drilling Program Leg 160. During the Pleistocene, the Troodos ophiolite was progressively unroofed, resulting in a near-radial pattern of coarse clastic sedimentation. The Pleistocene Fanglomerate Group depositionally overlies Pliocene marine sediments. Along the southern margin of the Troodos Massif the contact is erosional, whereas along its northern margin a regressive fan-delta (Kakkaristra Fm.) intervenes. The Pleistocene Fanglomerate Group is subdivided into four units (termed F1-F4), each of which were formed at progressively lower topographic levels. A wide variety of alluvial units are recognized within these, representing mainly high-energy coarse alluvial fans, channel fans, braidstream, and floodplain environments. A near-radial sediment dispersal pattern away from Mt. Olympos is indicated by paleocurrent studies, based on clast imbrication. Provenance studies indicate relatively early unroofing of the ophiolite, but with only minor localized erosion of ultramafic rocks from the Mt. Olympos area. Clasts of erosionally resistant lithologies, notably ophiolitic diabase and Miocene reefrelated limestone, are volumetrically over-represented, relative to friable basalt and early Tertiary pelagic carbonate sediments. The younger Fanglomerate Group units (F3 and F4) can be correlated with littoral marine terraces previously dated radiometrically at about 185-219 ka and 116-134 ka, respectively. However, the earlier (Fl and F2) Fanglomerate Group units can, at present, be dated only as early to middle Pleistocene. The principle variables that affected deposition of the Pleistocene Fanglomerate Group as a whole are tectonic uplift isostatic effects, glacio-eustatic sea-level change, short- and long-term climatic change, and lithology. However, the dominant control was tectonic uplift that apparently peaked during early and middle Pleistocene time. Aggradation of fluvial sediments (Fl and F2) took place at times of relative sea-level high with associated terrace formation. This was followed by downcutting during periods of relative sea-level fall when surface uplift continued. The dominant control on the younger (F3 and F4) units was glacio-eustatic sea-level change, during a time when littoral marine sediments accumulated, and rates of surface uplift may have decreased. Finally, the Holocene alluvial deposition was also affected by anthropogenic effects, notably deforestation.

The area around Ise Bay has been broken into many blocks by faultings. As subsiding blocks, Ise Bay and Nobi Plain are surrounded by 30 to 200 meters high hilly blocks and by upheaved mountain blocks ranging from 500 to 1200 meters high.The mountain blocks are made up of pre-Tertiary basement rocks. The hilly blocks are composed mainly of the Tokai Group; deposited in“Lake Tokai”, a sedimentary basin from Pliocene to Early Pleistocene time. The hilly blocks are extensively dissected by rivers and only a series of hill tops at approximately the same height is left as a remnant of the erosional surface in early stage. Older fluvial deposits, “the highest gravel”, unconformably overlie some of the hill tops. Younger fluvial deposits, the higher and lower terrace sediments, are developed along major valleys. Since these fluvial deposits consist mainly of gravelly sediments and the relative altitudes of surfaces of the terraces are modified by the movements of local fault blocks, detailed stratigraphic positions of these were not clear.Cenozoic sediments underlying the Nobi Plain attain 1500 meters in thickness. In the sequence of the sediments, a remarkable unconformity is recognized. The upper sediments, more than 350 meters thick, consist of alternating marine and fluvial sediments, suggesting that they were deposited under the influence of the glacial sea level oscillations. The lower sediments corresponding to the Tokai Group are unconformably overlain by the upper sediments. Microfossil analyses of a large number of drilling cores have clarified the stratigraphic succession of these sediments. The upper sediments are divided into four units: The lower Middle Pleistocene Yatomi Formation, the upper Middle Pleistocene Ama Formation, Upper Pleistocene formations, and Holocene sediments.The biostratigraphic information about the upper sediments furnishes valuable clue to the stratigraphic position of the fluvial deposits on land. Thus, the distribution pattern and altitude of these upper Quaternary sediments reveal the differential movements of each fault block surrounding Ise Bay.The Nobi Plain block has rapidly subsided since early Middle Pleistocene. Subsequently the gentle uplift in the hilly blocks occurred in the later Middle Pleistocene time, the stage of“the highest gravel”, and followed by the dissection of the hilly area. The subsidence of Ise Bay block may have started later than that of the Nobi Plain block, though the subsidence rates of both blocks have been of the same order since late Pleistocene.

Ecological transitions — But for whom? A perspective from the Pleistocene

Middle Pleistocene to Holocene fluvial terrace development and uplift-driven valley incision in the SE Carpathians, Romania

The present paper treats of the results of a detailed geomorphological investigation carried out along the lower course of the Vltava, and in the wide environment of the Labe, up stream from its confluence with the Vltava between Mělník and Roudnice n. L. Characteristic features of the morphology of the area under investigation are erosion-denudation phenomena on the one hand, and accumulation phenomena on the other. Erosion-denudation phenomena are represented by structural denudation plateaus occuring especially on the right bank of the Labe, and developed at several different levels. Their approximate age may be determined by their relation to the development and the genesis of the valley of the Labe, and especially, to the terraces. The oldest structural denudation plateaus occuring at a height of 325 m date from Later Tertiary (Pliocene), others are of Quarternary age (predominantly Early Pleistocene, rarely Middle Pleistocene, only exceptionally Late Pleistocene). In the north-eastern part of the mapped area, structural and tectonic conditions of cretaceous rocks played an important part in the origin of pictoresque sandstone cities as well as in the development of deeply incised canyons, which most often, follow the course of fissures and faults in the cretaceous sediments. The place of confluence of two main Bohemian rivers - the Labe and the Vltava - in the area between Říp and Mělník was shifted several times in the Quarternary. The most effectual influence upon the intricate development of water streams in this area exercised the basalt hill Říp nowadays situated in the middle of accumulations of Eearly Pleistocene terraces. The terrace material had been deposited mostly by the Vltava after it had left in the Algonkian its close valley before Kralupy n. V. Besides its petrological composition, this terrace material differs strikingly with its coarser grain from that deposited by the Labe. The uppermost river sands and gravels at northern foot of Říp and on the Sovice hill (at a height of 278 m-130 m above the surface of the Labe) most probably date from the Latest Neogene (Pliocene). Pleistocene terraces have developed here at all levels. A detailed study enabled us to determine in this area a terrace system different from the one on the Vltava (compiled by Q. Záruba 1942). Seven large Pleistocene terrace accumulations were distinguished which is less than Q. Záruba had distinguished on the Vltava. From these terrace accumulations we have excluded levels formed by lateral river erosion. In this way 15 terrace levels could be determined on the whole. From a comparison with the longitudinal profile drawn by Q. Záruba, becomes evident that his terraces Ib and II a form a single terrace accumulation (our terrace III), just as terraces IIIa and IIIb (our terrace V) and terraces IVa and IVb (our terrace VII). The Eolian accumulation in the area under investigation was composed of loess cover and loess drifts mostly of Middle and Late Pleistocene age, and of sedimented sands which form sand dunes mostly of west-eastern direction reaching in places the height of 5-6 m. They were blown here in Würm from river deposits. Periglacial processes resulted in ice-wedges and solifluction which asserted itself most strikingly at the foot of the basalt hill Říp where it formed a continuous solifluction cover of Early and Middle Pleistocene age strewn with boulders mixed with cretaceous debris and Eolian sediments. Periglacial processes together with the Eolian activity caused the asymmetrical development of some valleys (the best example is the valley of the brook Čepel in the place where it heads from south to north). The river network in this area passed through an intricate development, especially in the place of the confluence of the Vltava and the Labe. Changes of similar kind can best be traced on enlarged surfaces of terraces. In the Earliest Pleistocene at the time of terrace I, the Vltava skirted the eastern foot of Říp and devided into two branches at the time of accumulation of terrace II. The western branch headed from Velvary northwards, the eastern branch followed the western brim of the Horní Beřkovice Plateau and the northern side of the Krabčice Plateau towards the Labe which it joined most probably east of Libkovice p. Ř. At the time of origin of terrase III, the Vltava headed from Veltrusy towards north-north-west to Roudnice n. L., and farther towards north-west to the Lower Ohře. Its second branch most probably flew along the eastern side of Říp. The river Vltava shifted its stream permanently at the time of terrace IV. This terrace follows the lower course of the Vltava and the Labe along its present valley. At the time of terrace V the river started forming a large meander north-west of Cítov. At that time also the Roudnice meanders started developing (and have kept on doing so up to the present), as indicated by B. Zahálka (1946). B. Zahálka presumes the main cause is the hill Sovice built of rocks hardened with basalt. The Cítov meander was abandoned by the river as early as in the erosion phase between terrace V and VI. Simultaneously with the origin of terrace VI the basalt Jenišovice hill was exhumed. The largest part of the Labe stream flew through the tectonic depression of Mělník, the side stream most probably through its present valley. At the time of terrace VII, the Vltava skirted on all sides the foot of the Jenišovice hill with the remains of the plateau of terrace VI. At the time following the origin of the terrace level VIIb, the Vltava was captured by the Labe in the place of their present confluence under Mělník, whereas before that the place of their confluence had been constantly moving up-stream. At the time of terrace VI both rivers most probably joined somewhere in the vicinity of Dolní Beřkovice. The most important factor for the development of relief in the area under investigation was the erosion and accumulation activity of rivers, which gave rise to terrace levels. In our opinion - based upon studies carried out in this area - during the deepening of the valley, after the accumulation of the terrace sediments, the river started cutting down into its own deposits, and forming - through lateral erosion - lower levels on the gradually narrowing valley floor. Through a further intense deepening, the river cut through its own sediments and their substratum down to the comparatively narrow floor of a more or less outstanding depression in the valley bottom, and is consequently the lowest place of the next terrace. In the period of accumulation, the river deposited first of all its sand-gravel load in this depression; upwards, valleys widened to the detriment of the deposits of higher-situated terraces and the cretaceous substratum. The upper layer of the terrace sediments was deposited as high as the level of the accumulation surface of the terrace. Processes of accumulation and lateral erosion participate in the origin of terraces. The main erosion phase of the development of the valley dates from the time succeeding the deposition of terrace IV, and from the time of the origin of Middle Pleistocene terraces, at which time valleys of main rivers and their tributaries were deepened. Valleys (mostly dry) and valley depresions, dividing plateaus of Middle and Early Pleistocene terraces in the area of the Říp plateau, originated already in Earlier Pleistocene and acquired their present form in Middle Pleistocene. In Later Pleistocene numerous short valley depressions were deepened no more. There are mostly fossil phenomena formed in periglacial climate in conection with the erosion phases of the main streams. The oldest network of valleys dating from as early as Younger Tertiary occurs on the right bank of the Labe in the Jizera Plateau and Polomené Hills. Practically no changes in the course of valleys took place in Pleistocene, they kept just on cutting down most intensively. The youngest erosion processes manifested themselves in the deepening both of valleys and valley depressions, and in the formation of deep gorges.

Early and Middle Pleistocene of North America

Glacial, fluvial and volcanic landscape evolution in the Laguna Potrok Aike maar area, Southern Patagonia, Argentina

GLACIATIONS | Mid-Quaternary in North America

Mid-Quaternary in North America

Biostratigraphic correlation of Pleistocene marine deposits and sea levels, Atlantic coastal plain of the southeastern United States