Late Cenozoic History Research Articles

Late Cenozoic history and the role of Beringia in assembling a Holarctic cestode species complex

The dynamic climate history that drove sea level fluctuation during past glacial periods mediated the movement of organisms between Asia and North America via the Bering Land Bridge. Investigations of the biogeographic histories of small mammals and their parasites demonstrate facets of a complex history of episodic geographic colonization and refugial isolation that structured diversity across the Holarctic. We use a large multi-locus nuclear DNA sequence dataset to robustly resolve relationships within the cestode genus Arostrilepis (Cyclophyllidea: Hymenolepididae), a widespread parasite of predominantly arvicoline rodents (voles, lemmings). Using this phylogeny, we confirm that several Asian Arostrilepis lineages colonized North America during up to four distinct glacial periods in association with different rodent hosts, consistent with taxon-pulse dynamics. A previously inferred westward dispersal across the land bridge is rejected. We also refine interpretations of past host colonization, providing evidence for several distinct episodes of expanding host range, which probably contributed to diversification by Arostrilepis. Finally, Arostrilepis is shown to be paraphyletic with respect to Hymenandrya thomomyis, a parasite of pocket gophers, confirming that ancient Arostrilepis species colonized new host lineages upon arriving in North America.

An araphid diatoms from marine Miocene deposits of the Fisher Massif (Prince Charles Mountains, East Antarctica)

The Late Cenozoic history of Antarctica is reflected in the few ice-free ground deposits of the continental marginal zone. While the planktonic diatom flora of the Cenozoic Antarctic, which has dominated the biocenoses of the Southern Ocean since the Eocene, has been fairly well studied based on Deep-Sea Drilling, the benthic diatoms found in sediments have been studied extremely poorly. In the materials collected during the 52nd and 53rd Russian Antarctic expeditions in 2006–2008 from deposits of the Fisher Massif (central part of the Prince Charles Mountains), a rich fossil diatom complexes were found, including more than 80 mainly benthic taxa. Of these, 13 species of araphid diatoms have been studied and described.

Plio-Quaternary landscape evolution in the uplifted Ardennes: New insights from 26Al/10Be data from cave-deposited alluvium (Meuse catchment, E. Belgium)

Despite a wealth of recent studies dealing with the evolution of the drainage network in the uplifted Ardennes massif (E. Belgium), especially from the Middle Pleistocene onwards, the Ardennian landscape evolution and long-term incision rates in the Meuse catchment remain poorly documented over the whole Plio-Quaternary. Alluvium-filled multilevel cave systems represent a relevant setting to unravel the Late Cenozoic history of regional river incision. We present here a dataset of 26Al/10Be concentration data obtained from fifteen pebble samples washed into the Chawresse system, one of the largest multi-level cave systems of Belgium, which developed in Devonian limestones of the lower Ourthe Valley, the main Ardennian tributary of the Meuse. The sample collection spans an elevation difference higher than 120 m and their depleted 26Al/10Be ratios yield burial ages ranging from ~0.25 to 3.28 Ma. After critical assessment of our dataset for intra-karstic reworking issues, the most striking outcome of the obtained burial ages is the acceleration by a factor five of the incision rates (from ~30 to ~150 m/Ma) during the first half of the Middle Pleistocene. Integrating this incision peak and our pre-burial denudation rates, we then revisit the existing framework of Plio-Quaternary denudation and river incision in the Ardennian Meuse catchment. Whilst our 26Al/10Be concentration data shed new light on the temporal and spatial variability of the local river and hillslope system response to coupled tectonic and climatic forcings, it simultaneously highlights sampling issues and the need for further chronological data.

North Platte River-South Platte River Confluence Area Drainage System History as Determined by Topographic Map Interpretation: Western Nebraska, USA

Detailed topographic maps of the western Nebraska North Platte River-South Platte River confluence area show a low relief and gently sloping southeast-oriented upland surface, asymmetrical drainage divides, nearly adjacent and parallel east-oriented North and South Platte River valley segments, barbed tributaries, and shallow divide crossings (low points along drainage divides) in a region south of the Nebraska Sand Hills and at the Nebraska loess region’s western margin. Published interpretations of North and South Platte River confluence area landforms (referred to as the accepted paradigm) do not explain most drainage features and are compared with a new paradigm’s interpretations to determine which of the two paradigms explains the regional drainage history and related surface features in a simple and consistent manner. New paradigm interpretations require large sheets of slowly-moving southeast-oriented water to have flowed toward what was probably an actively eroding Republican River valley and to have shaped the upland surface while the Platte and North and South Platte River valleys eroded headward into and across the region so as to create the asymmetric drainage divides, barbed tributaries, and shallow divide crossings. These new paradigm interpretations are consistent with each other and with recently published new paradigm interpretations of upstream North and South Platte River drainage system history. New paradigm interpretations also suggest the adjacent Nebraska Sand Hills developed on a large flood deposited delta (typical of sand dune areas on former glacial lake deltas further to the north) and the slowly-moving sheets of water may have been responsible for some or all of Nebraska’s loess deposits, although the new paradigm leads to a fundamentally different middle and late Cenozoic regional geologic and glacial history than what workers using the accepted paradigm have described.

Late Mesozoic and Cenozoic thermo-tectonic history of Eastern, Central and Southern Mexico as determined through integrated thermochronology, with implications for sediment delivery to the Gulf of Mexico

Late Mesozoic and Cenozoic thermo-tectonic history of Eastern, Central and Southern Mexico as determined through integrated thermochronology, with implications for sediment delivery to the Gulf of Mexico

Topographic Map Analysis of Mountain Passes Crossing the Continental Divide Between Colorado River Headwaters and North and South Platte River Headwaters to Test a New Geomorphology Paradigm, Colorado, USA

Detailed topographic maps are used to identify and briefly describe named (and a few unnamed) mountain passes crossing high elevation east-west continental divide segments encircling south- and southwest-oriented Colorado River headwaters and linking the Colorado River drainage basin (draining to the Pacific Ocean) with the North and South Platte River drainage basins (draining to the Platte, Missouri, and Mississippi Rivers and Gulf of Mexico). Previous researchers following commonly accepted geomorphology paradigm rules have not explained how most, if any of these mountain passes originated. A recently proposed geomorphology paradigm requires all Missouri River drainage basin valleys to have eroded headward across massive south- and southeast-oriented floods, which implies south- and southeast-oriented floods flowed from what are today north-oriented North Platte River headwaters across the continental divide, the present-day south- and southwest-oriented Colorado River headwaters valley, and then across what is now the continental divide a second time to reach east- and southeast-oriented South Platte River headwaters. Paradigms are rules determining how a scientific discipline governs its research and by themselves are neither correct nor incorrect and are judged on their ability to explain observed evidence. From the new paradigm perspective, a stream eroded each of the passes into a rising mountain range until the uplift rate outpaced the erosion rate and forced a flow reversal in what would have been the upstream valley. The passes and the valleys leading in both directions from the continental divide are best explained if diverging and converging south- and southeast-oriented flood flow channels crossed rising mountain ranges. While explaining observed drainage patterns and erosional landforms such an interpretation requires a fundamentally different regional middle and late Cenozoic glacial and geologic history than what previous investigators using the accepted paradigm perspective have described.

Inversion of Dadu River Bedrock Channels for the Late Cenozoic Uplift History of the Eastern Tibetan Plateau

AbstractThe Dadu River in the eastern Tibetan Plateau has the potential to record transient variations of tectonic uplift since the Late Cenozoic. In this study, we extracted bedrock channels of the Dadu River drainage basin from the 30 m ASTER digital elevation model. The longitudinal river profiles were then analyzed, and three generations of knickpoints were recognized via the slope area method. By solving the analytical solution of the linear transient stream power incision model, we determined a Late Cenozoic history of regional tectonic uplift. The results reveal slow pre–middle Miocene uplift rates (<0.1 mm/a) and then increased gradually to 0.33 ± 0.03 mm/a since 12–15 Ma until present. This increase of uplift rate from bedrock channel inversion is consistent with the regional findings of low‐temperature themochronology, emphasizing the potential and significance to utilize channel profiles to infer the tectonic uplift history.

Use of Topographic Map Evidence From Drainage Divides Surrounding Wyoming’s Great Divide Basin to Compare Two Fundamentally Different Regional Geomorphology Paradigms

Divide crossings (or low points or gaps) notched into the North American east-west continental divide segments completely encircling Wyoming’s Great Divide Basin interior drainage region (as observed on detailed topographic maps) are used to compare the commonly accepted regional geomorphology paradigm with a fundamentally different and new regional geomorphology paradigm. Paradigms are sets of rules governing how a scientific discipline conducts its research and are judged on their ability to explain observed evidence. Published literature is used to contrast an accepted paradigm interpretation that east-oriented drainage previously flowed across what is now the Great Divide Basin with the new paradigm basic requirement that mountain range and continental divide uplift occurred while immense south-oriented floods flowed across them. Numerous divide crossings are notched into the continental divide segments now completely encircling the relatively flat-floored Great Divide Basin interior drainage area and divide crossings observed along each of the Great Divide Basin’s north, east, south, and west margins are described and interpreted first from the accepted paradigm perspective (using published literature interpretations to the extent possible) and second from the new paradigm perspective. The published literature does not mention most of the described divide crossings, much less provide explanations for their origins, perhaps because the accepted paradigm cannot satisfactorily explain those origins. In contrast the new paradigm successfully explains most if not all of the described (and observed, but undescribed) divide crossings, although the new paradigm requires a completely different middle and late Cenozoic regional geologic history than what most published regional geology literature describes.

Upper Miocene-Quaternary magnetostratigraphy and magnetic susceptibility from the Bohai Bay Basin (eastern China) and implications for regional volcanic and basinal subsidence history

The thick Cenozoic sequence of alluvial, lacustrine, volcaniclastic, and marine sediments in the Bohai Bay Basin (BBB) of eastern China is an important sedimentary archive for studying the regional Late Cenozoic history of volcanism, tectonism, and paleoclimate changes, as well as the evolution of the East Asian monsoon system. However, well-dated deep drillcores are sparse in this region, which has prevented a comprehensive analysis of these issues. Here, we present the results of a detailed magnetostratigraphic and magnetic susceptibility study of two deep drillcores (G2 and G3) from the Huanghua Depression, with the aims of (1) refining the upper Miocene-to-Recent chronostratigraphic framework and subsidence history of the BBB, and (2) investigating its relationship to regional volcanic and tectonic events. The observed pattern of paleomagnetic polarity zones in Core G3 can be correlated well to the geomagnetic polarity time scale (GPTS). Quaternary-age peaks in the magnetic susceptibility profiles of Cores G2 and G3 may record large volcanic eruptions―they can be matched to similar peaks in other BBB drillcores, demonstrating their potential utility as regional marker horizons. Increased sedimentation rates in the study cores at ~8.0–6.4 Ma and 3.6–3.0 Ma reflect late Miocene uplift of the Taihang and Lvliang Mountains and late Pliocene BBB subsidence, respectively. Integrated into a regional framework for the upper Miocene to Recent, our magnetostratigraphic data show that subsidence of the Huanghua Depression increased from southwest to northeast.

A New Approach to 40Ar/39Ar Dating of Combustion Events: A Case Study from the Late Pleistocene Coal Fires in Goose Lake Depression (Transbaikalia)

Based on the study results of combustion metamorphic (CM) rocks from the young (0.01–0.06 kyr) CM complex at the Goose Lake brown coal deposit, a new approach to 40Ar/39Ar dating of coal paleofires was substantiated. The results of 40Ar/39Ar dating of K–Na feldspars (0.10 ± 0.16 Ma) from fragments of quartz syenites (initial age 285–305 Ma), enclosed in paralavas and heated by fire (T ≥ 950°С) show that magmatic feldspars have lost all radiogenic argon during combustion event. As follows from the numerical modeling results, feldspars (diffusion domains of 100 μm in size) can lose all radiogenic argon under heating (T = 950°C) in five hours. The estimated data have proved that grains of detrital feldspars enclosed in sediments that were subject to heating must be completely degassed over the time of existence of large fire focus. It means that glassy (T ≥ 900°C) CM rocks with relics of K–Na feldspars are applicable for correct 40Ar/39Ar dating of combustion metamorphic paleoevents. The abundance of such rocks in the CM sections promotes opportunities for geochronological reconstructions of the Late Cenozoic history of sedimentary basins.

Deep Erosion by Continental Ice Sheets: A Northern Missouri River Drainage Basin Perspective: North America

While accepting some erosion by continental ice sheets most geologists reject a previously proposed deep erosion by continental ice sheets hypothesis, yet common sense logic suggests continental ice sheets should have eroded much more than they are usually given credit for. Such situations arise in scientific communities when an accepted paradigm cannot adequately explain significant observable evidence. A new and fundamentally different paradigm, constructed from detailed topographic map evidence, illustrates how deep erosion (and crustal warping) by at least one continental ice sheet explains previously unexplained northern Missouri River drainage basin erosional landform origins. The new paradigm requires at least one North American continental ice sheet to have created (by deep erosion and by ice sheet related crustal warping) a deep “hole” in which the ice sheet was located. Late during that ice sheet’s melt history north- and northeast-oriented valleys eroded headward from that deep “hole’s” southern end to capture immense southeast-oriented ice-marginal melt-water floods and to create what are today north- and northeast-oriented Missouri River headwaters and tributary drainage routes. While successfully explaining numerous previously unexplained erosional landforms the new paradigm challenges a number of commonly accepted middle and late Cenozoic geologic and glacial history interpretations.

Stable carbon and oxygen isotopic evidence for Late Cenozoic environmental change in Northern China

Stable carbon and oxygen isotope ratios of 311 enamel samples from a diverse group of herbivorous mammals including Equidae, Rhinocerotidae, Bovidae, Rodentia and Ochotonidaewere were analyzed in order to reconstruct the Late Cenozoic history of vegetation and environmental change in the Yushe Basin in North China. The δ13C values of bulk and serial enamel samples from large mammals show a wide range of variation from −13.3‰ to 1.4‰, with a mean of −7.4‰±3.5‰ (n=294). This indicates that large herbivorous mammals in the area had a variety of diets since 6.5Ma, ranging from pure C3 to mixed C3–C4 and pure C4 diets. In contrast, the δ13C values of small mammals vary from −11.9‰ to −7.6‰, with a mean of −9.7±1.1‰ (n=17), indicating that rodents and ochotonids were feeding mostly on C3 plants. Variations in δ13C values within and between species reflect the variations in the habitat and the vegetation consumed by the animals. In general, horses had higher amounts of C4 grasses in their diets than other contemporary taxa such as bovids, rhinos, rodents and deer, suggesting that horses exploited more open habitats such as grasslands while deer, rhinos and rodents may have preferred more C3 vegetation, which is more indicative of forested environments. The carbon isotope data show that C4 grasses have been an important component of horses' diets and of local ecosystems since ~6.5Ma, confirming that the “late Miocene C4 expansion” occurred in North China as it did in Africa, Indian subcontinent and the Americas. This supports a global factor as a main driver of the late Miocene C4 expansion. The combined carbon and oxygen isotope data reveal major shifts in climate to drier and/or warmer conditions after ~5.8, ~4.1, ~3.3, and ~2.5Ma, and significant shifts to relatively wetter and/or cooler conditions after ~6.4, ~5, ~3.5Ma. The shifts to drier and/or warmer climate after ~5.8Ma and ~2.5Ma coincide with two major fauna turnover events. Intra-tooth δ13C and δ18O values are negatively correlated within individual modern teeth and some fossil teeth, displaying the characteristic pattern of the summer monsoon regime and confirming a strong monsoon influence in the area since at least the early Pliocene. The data also suggest that the C4 abundance in the area has fluctuated over the past 6.5Ma in response to changes in climate, with more C4 grasses during warmer and/or drier periods and a reduced C4 component at cooler and/or wetter times.

Constraints on the tectonic and landscape evolution of the Bhutan Himalaya from thermochronometry

The observed geomorphology and calculated thermal histories of the Bhutan Himalaya provide an excellent platform to test ideas regarding the influence of tectonics and climate on the evolution of a convergentmountain range. However, little consensus has been reached regarding the late Cenozoic history of the Bhutan Himalaya. Some researchers have argued that observed geologic relationships show slowing deformation rates, such that the range is decaying from a geomorphic perspective, while others see the range as growing and steepening. We suggest that a better understanding is possible through the integrated interpretation of geomorphic and thermochronometric data from the comparison of predictions from models of landscape evolution and thermal-kinematic models of orogenic systems. New thermochronometric data throughout Bhutan aremost consistent with a significant decrease in erosion rates, from2 to 3 km/Ma down to 0.1–0.3 km/Ma, around 6–4Ma. We interpret this pattern as a decrease in rock uplift rates due to the activation of contractional structures of the Shillong Plateau, an uplifted region approximately 100 km south of Bhutan. However, low-relief, fluvial landscapes throughout the Bhutanese hinterland record a late pulse of surface uplift likely due to a recent increase in rock uplift rates. Constraints from our youngest thermochronometers suggest that this increase in rock uplift and surface uplift occurred within the last 1.75Ma. These results imply that the dynamics of the Bhutan Himalaya and Shillong Plateau have been linked during the late Cenozoic, with structural elements of both regions active in variable ways and times over that interval.

Geology of Unaweep Canyon and its role in the drainage evolution of the northern Colorado Plateau

Unaweep Canyon (Colorado, USA) is a large, Precambrian-cored gorge that bisects the Uncompahgre Plateau of the northeastern Colorado Plateau, but has no through-flowing axial stream; it is drained by two underfit creeks (East and West Creek) that head at a divide within the canyon. The history of the canyon and its role in drainage evolution of the Colorado River system remain controversial. New mapping of both bedrock and Quaternary units as well as analyses of Quaternary deposits in and near the canyon shed light on its late Cenozoic history, and call into question whether the canyon was incised by a Cenozoic river, or merely exhumed by one. Gravels near the western mouth of Unaweep Canyon (Gateway, Colorado) exhibit a distinctive intermediate volcanic provenance recording the presence of an ancestral Gunnison River; the youngest gravels are dated to 1.46 ± 0.33 Ma. Previously documented coring within the canyon reveals a thick (locally >330 m) fill that includes a lacustrine succession (∼140 m thick), dated to 1.4–1.3 Ma, overlain by stacked paleosols and a thick (∼160 m) conglomeratic unit emplaced between 1.3 Ma and the present, in addition to a basal unit of possible late Paleozoic age. Lake formation reflects catastrophic mass wasting in western Unaweep Canyon that blocked the ancestral Gunnison River, causing partial backfilling of the canyon, and forcing the river to seek a lower elevation exit eastward by breaching the Mesozoic rim at the northeast end of Cactus Park (Mesa County, Colorado). Ultimately, the ancestral Gunnison River joined the lower elevation Colorado River near Grand Junction by 1.3 Ma, incising the East Creek of Unaweep Canyon during the overspilling event. Thermochronological data from Precambrian basement within Unaweep Canyon and Permian strata at the western mouth of the canyon indicate onset of incision in latest Miocene time (ca. 6–5 Ma), at a time-averaged rate of ∼210–275 m/m.y. Onset of canyon occupation and rapid incision by the ancestral Gunnison River coincided with the timing of integration of the lower Colorado River system to the Gulf of California. The synchroneity of this incision across the Colorado Plateau supports the inference of an ultimate tectonic or epeirorogenic driver for this widespread incision and ultimate drainage integration. Several aspects of this data set support the previously published hypothesis that the ancestral Gunnison River exhumed a paleovalley. New mapping at the western mouth of the canyon documents a paleovalley filled with Permian strata that leads into the modern Precambrian-hosted gorge of Unaweep Canyon. In addition, the ancestral Gunnison River paralleled the Uncompahgre Plateau before making a 90° turn to bisect the structural axis in a manner that opposes both the northwestward plunge of the uplift and the northeastward dip of its northern flank. The rate of incision of Unaweep Canyon exceeds regional time-averaged incision rates, consistent with removal of sedimentary fill rather than incision of crystalline basement. This hypothesis implies that very ancient landforms can influence drainage evolution in even tectonically active landscapes.

Late Cenozoic History of the Genus Micromys (Mammalia, Rodentia) in Central Europe

Molecular phylogeography suggests that Micromys minutus, the sole extant species of the genus, colonized its extensive range quite recently, during the Late Pleistocene-Holocene period. Rich Pliocene and Pleistocene fossil records both from Europe and China suggest rather continuous and gradual in situ phenotype rearrangements from the Pliocene to the Recent periods. To elucidate the discrepancy we reexamined a considerable part of the European fossil record of the genus (14 sites from MN15 to Q3, 0.4–4.2 Ma, including the type series of M. preaminutus from MN15 Csarnóta 2), analyzed them with the aid of detailed morphometric comparisons, and concluded that: (a) The European Pliocene form, M. praeminutus, differs significantly from the extant species; (b) it exhibits a broad phenotypic variation covering the presumptive diagnostic characters of MN16 M. caesaris; (c) despite having smaller dimensions, the Early and Middle Pleistocene forms (MN17-Q3, 2.6–0.4 Ma) seem to be closer to M. praeminutus than to the extant species; (d) the extinction of M. praeminutus during Q3 and the re-occupation of its niche by the recent expansion of M. minutus from E-European – C Asiatic sources (suggested by phylogeographic hypotheses) cannot be excluded. Discussing interpretations of the phylogenetic past of the genus we emphasize the distinct history of the West Palearctic clade (Late Miocene-Early Pleistocene) terminating with M. praeminutus and the East Asiatic clade (chalceus, tedfordi, minutus), and the possible identity of the Western clade with the Late Miocene genus Parapodemus.

Quaternary biostratigraphy and biochronology of the West Siberian plain: trans-regional and trans-zonal correlations

Summarized information is given on the Upper Pliocene–Pleistocene deposits of the Southern Urals with data on the distribution of significant ostracod species, molluscs, large and small mammals and plant remains.The Late Cenozoic history of the Southern Urals is characterized by transgression of the Akchagylian Sea, which ingressed all river valleys of the Southern Fore-Urals during the Pliocene. The Pleistocene deposits in the area are of continental origin. The Pleistocene cover glaciations did not reach the Southern Urals; however, the Quaternary climatic fluctuations affected the history of the fauna, flora and human societies, as well as the geomorphological character of the area. The development of the territory was governed by a general activization of tectonic movements and a quick uplift of the surface. This event belongs to the most recent stage of the geological history of the Urals. According to recent fission-track data, the age of the relics of a peneplain preserved in the tops of the Ural Mountains is hardly older than the Cretaceous, which contradicts the traditional point of view. The period of formation of the modern Ural Mountains is probably also much shorter than is usually thought and corresponds mainly to Pliocene-Quaternary times.The Southern Urals is an important area for correlation between the European and Siberian/Asiatic stratigraphic schemes. To improve the correlation between these two areas and to expand our understanding of the complex geology of the area, future (bio)stratigraphical investigation of the Pliocene–Pleistocene deposits of the Southern Urals region is necessary.

Late Cenozoic history of deep water circulation in the western North Pacific: Evidence from Nd isotopes of ferromanganese crusts

Despite its importance in regulating the global climate, the past deep ocean circulation in the western North Pacific has still been poorly understood. Nd isotopes of ferromanganese crusts have been proven to be a good proxy to monitor paleoceanic circulation changes. In this study, late Cenozoic Nd isotopic records are recovered from two ferromanganese crusts located near Mariana arc but at different water depths (MKD13: 1530 m, MDD53: 2700 m), and their implications for paleocirculation change in this area are explored. From the early to late Miocene, Nd isotopic compositions of MDD53 remained stable, and they were also characterized by the least radiogenic signatures (ɛNd −4.0 to −5.0) compared to crusts of similar water depths in the Miocene North Pacific. Afterward, an abrupt increase in its ɛNd value occurred in the Pliocene. In contrast, Nd isotopes of MKD13 became more radiogenic with time in the Miocene and were almost invariable thereafter. The continual increase in ɛNd of shallower crust MKD13 is interpreted as reflecting progressive closure of Indonesian Seaway in the Miocene, while the deep western boundary current sourced from the Southern Pacific may have dominated Nd isotopes of deeper crust MDD53 during the same time interval. The lack of Nd isotopic variation of MKD13 in the Pliocene indicates that there were no changes in Nd sources in shallower waters and the final restriction between the Indian and Pacific may have only occurred since then. Therefore the observed large shift to more radiogenic Nd isotopes of MDD53 in the Pliocene should not be resulted from changes in vertical input from shallower to deeper water. Instead, a decreased ventilation of deep southern component current along the studied water depth range (∼2700 m) may have continued in the Pliocene.

Book review: Past environmental change in Latin America

ISSN 1948‐6596 It is exciting to see such dynamic develop‐ ment of new approaches to island biogeography; whether one studies metapopulation dynamics, conservation biogeography, or adaptive radiations on oceanic islands, the field of island biogeogra‐ phy continues to offer broad horizons. If it is true that the paradigm initiated by MacArthur and Wil‐ son is being supplanted in both ecological and evolutionary island biogeography, the new para‐ digms owe much of their development to the ro‐ bust research agenda laid out 40 years ago. References news and update MacArthur, R.H. & Wilson, E.O. (1967) The theory of island biogeography. Princeton University Press, Princeton. Lawrence R. Heaney Field Museum of Natural History, Chicago, IL, USA e‐mail: lheaney@fieldmuseum.org http://fm1.fieldmuseum.org/aa/ staff_page.cgi?staff=lheaney Edited by Markus Eichhorn and Joaquin Hortal MacArthur, R.H. & Wilson, E.O. (1963) An equilibrium theory of insular zoogeography. Evolution, 17, book review Past environmental change in Latin America Late Cretaceous and Cenozoic History of Latin America Vegetation and Terrestrial Environments, by Alan Graham Missouri Botanical Garden Press, Flora Mesoamericana Vol. 4(1), June 2010, 617 pp. ISBN: 978‐ Price: $95.00 (Hardback) http://www.mbgpress.info/ This authoritative text by Prof. Alan Graham of the Missouri Botanic Gardens is based upon nearly four decades of research in the Neotropics. The volume provides a comprehensive foundation for understanding the past environmental change that underlies the biogeographic patterns found in Latin America (defined as 32 o N to 55 o S), and is a companion volume to his earlier work which fo‐ cused upon North America (Graham, 1999), in ad‐ dition to another recent book on the pa‐ laeoecological history of the New World (Graham, 2010 1 ). The introductory note to the Latin America book states that the target level is advanced un‐ dergraduate and graduate students, and that the aim is to be appropriate for use within university courses and seminars. In my opinion this book achieves this goal by providing up‐to‐date infor‐ mation in a well organised, concise and interesting manner. The book is logically set out and written in an easily‐digestible style which should be under‐ stood by most undergraduate students. Divided into three sections (Background, Database and Synthesis) and eight chapters, there is a natural progression in the format, which means that the text could easily be utilised as a support for a seminar series or lecture course. The background section contains a wealth of basic information on the climate, geography, geology and vegetation, which provides the scene‐setting details which would be required for any undergraduate lecture series on the past environments of Latin America. The clear and consistent geographic organisation of chapters and subsections also lends itself to the teacher or student who wishes to extract informa‐ tion on a particular region of interest; Mexico, the Antilles, Central America or South America. A review of this book will appear in a future issue of Frontiers of Biogeography. frontiers of biogeography 2.4, 2011 — © 2011 the authors; journal compilation © 2011 The International Biogeography Society

Sedimentary cover and late Cenozoic history of the Okushiri Ridge (Sea of Japan)

A complex (petrographic, micropaleontological, and X-ray diffraction) investigation of the sedimentary cover on the northwestern slope of the Okushiri Ridge in the Sea of Japan revealed that its basal layers are of Oligocene age and composed of terrigenous silty-clayey sediments, which were deposited in coastalmarine environments with calm hydrodynamics and low sedimentation rates. The relative sea-level rise combined with regional tectonic processes at the early-middle Miocene transition resulted in widening and deepening of sea basins and accumulation of a thick diatomaceous-clayey sequence of middle-upper Miocene sediments. Tectonic activation in the Pliocene was responsible for development of the ridge and exhumation of rocks formerly occurring at depth of 500–1000 m.

Early Pleistocene vegetation change in upland south-eastern Australia

Aim This study aims to improve our understanding of the late Cenozoic history of Australian rain forest and sclerophyll biomes by presenting a detailed pollen record demonstrating the floristic composition and orbital-scale patterns of change in forest communities of upland south-eastern Australia, during the Early Pleistocene. The record is examined in order to shed light on the nature of the transition from rain forest-dominated ‘Tertiary’ Australian vegetation to open-canopied ‘Quaternary’ vegetation. Location Stony Creek Basin (144.13° E, 37.35° S, 550 m a.s.l), a small, infilled palaeolake in the western uplands of Victoria, Australia. Methods A c. 40-m-long sediment core was recovered from the infilled palaeolake. Palynology was used to produce a record of changing vegetation through time. Multivariate analyses provided a basis for interpreting the composition of rain forest and sclerophyll forest communities and for identifying changes in these communities over successive insolation cycles. Results Early Pleistocene upland south-eastern Australian vegetation was characterized by orbital-scale, cyclic alternation between rain forest and sclerophyll forests. Individual intervals of forest development underwent patterns of sequential taxon expansion that recurred in successive vegetation cycles. Diverse rain forests included a number of angiosperm and gymnosperm taxa now extinct regionally to globally. Sclerophyll forests were also diverse, and occurred under warm and wet climate conditions. Main conclusions The Stony Creek Basin record demonstrates that as recently as c. 1.5 Ma diverse rain forests persisted in southern Australia beyond the modern continental range of rain forest. The importance of conifers in these rain forests emphasizes that they have no modern Australian analogue. Alternation in dominance between these forests and diverse, sclerophyllous open canopied forests was apparently driven by changes in seasonality, and may have been promoted by fire.