Philip L. Gibbard

Are we now living in the Anthropocene

The term Anthropocene, proposed and increasingly employed to denote the current interval of anthropogenic global environmental change, may be discussed on stratigraphic grounds. A case can be made for its consideration as a formal epoch in that, since the start of the Industrial Revolution, Earth has endured changes sufficient to leave a global stratigraphic signature distinct from that of the Holocene or of previous Pleistocene interglacial phases, encompassing novel biotic, sedimentary, and geochemical change. These changes, although likely only in their initial phases, are sufficiently distinct and robustly established for suggestions of a Holocene–Anthropocene boundary in the recent historical past to be geologically reasonable. The boundary may be defined either via Global Stratigraphic Section and Point (“golden spike”) locations or by adopting a numerical date. Formal adoption of this term in the near future will largely depend on its utility, particularly to earth scientists working on late Holocene successions. This datum, from the perspective of the far future, will most probably approximate a distinctive stratigraphic boundary.

Glacial deposits in north-west Europe

Until now no overview of the Quaternary deposits of northeastern Europe has been available. This book fills the gap. It presents the state of research on Quaternary stratigraphy and geology, with emphasis on glacial deposits, discusses the general scientific ideas and gives an overview of the methods of investigation, some of which have rarely been applied elsewhere. It has become apparent that the region covered has many environmental problems, and a proper understanding of the Quaternary deposits is a basic requirement for dealing with them. The same is true for civil engineering. In the formerly glaciated areas almost all construction sites for roads and houses will encounter glacial deposits. This volume provides an authoritative and fascinating overview for anyone planning to venture into this field. In its 53 regional chapters the book covers Finland, Estonia, Latvia, Lithuania, Russia, Ukraine, Belarus, Poland, the Czech Republic and eastern Germany. From the text it becomes clear that not all the stratigraphical schemes are yet fully compatible or comprehensible. There can be no doubt, however, that the east was subjected to very extensive ice advances during the earlier Pleistocene. Also, in contrast to western Europe, there was a significant Early Weichselian ice advance, although not as extensive as the last, Late Weichselian event. The book is illustrated by 421 figures and 74 colour plates (mostly photographs). There are 23 tables, a detailed index and a list of over 1000 references, providing a unique collection of northeastern European geoscience literature, much of which has so far escaped the attention of western scientists. The volume, composed of contributions by 60 scientists, completes the trilogy on glacial deposits of northern Europe. Together with its two companion volumes, the Glacial deposits in North-West Europe and the Glacial Deposits in Great Britain and Ireland, it represents an invaluable source of information for the geoscientist, the advanced student or the amateur.

Early-Middle Pleistocene transitions: an overview and recommendation for the defining boundary

Abstract The Early-Middle Pleistocene transition (c. 1.2–0.5 Ma), sometimes known as the ‘mid-Pleistocene revolution’, represents a major episode in Earth history. Low-amplitude 41-ka obliquity-forced climate cycles of the earlier Pleistocene were replaced progressively in the later Pleistocene by high-amplitude 100-ka cycles. These later cycles are indicative of slow ice build-up and subsequent rapid melting, and imply a transition to a strongly non-linear forced climate system. Changes were accompanied by substantially increased global ice volume at 940 ka. These climate transformations, particularly the increasing severity and duration of cold stages, have had a profound effect on the biota and the physical landscape, especially in the northern hemisphere. This review assesses and integrates the marine and terrestrial evidence for change across this transition, based on the literature and especially the following 17 chapters in the present volume. Orbital and non-orbital climate forcing, palaeoceanography, stable isotopes, organic geochemistry, marine micropalaeontology, glacial history, loess-palaeosol sequences, pollen analysis, large and small mammal palaeoecology and stratigraphy, and human evolution and dispersal are all considered, and a series of discrete events is identified from Marine Isotope Stage (MIS) 36 (c. 1.2 Ma) to MIS 13 (c. 540–460 Ma). Of these, the cold MIS 22 (c. 880–870 ka) is perhaps the most profound. However, we here endorse earlier views that on practical grounds the Matuyama-Brunhes palaeomagnetic Chron boundary (mid-point at 773 ka, with an estimated duration of 7 ka) would serve as the best overall guide for establishing the Early-Middle Pleistocene Subseries boundary.

Stratigraphy of the Anthropocene

The Anthropocene, an informal term used to signal the impact of collective human activity on biological, physical and chemical processes on the Earth system, is assessed using stratigraphic criteria. It is complex in time, space and process, and may be considered in terms of the scale, relative timing, duration and novelty of its various phenomena. The lithostratigraphic signal includes both direct components, such as urban constructions and man-made deposits, and indirect ones, such as sediment flux changes. Already widespread, these are producing a significant ‘event layer’, locally with considerable long-term preservation potential. Chemostratigraphic signals include new organic compounds, but are likely to be dominated by the effects of CO2 release, particularly via acidification in the marine realm, and man-made radionuclides. The sequence stratigraphic signal is negligible to date, but may become geologically significant over centennial/millennial time scales. The rapidly growing biostratigraphic signal includes geologically novel aspects (the scale of globally transferred species) and geologically will have permanent effects.

Early and early Middle Pleistocene correlations in the Southern North Sea basin

Abstract On April 8, 1988 a discussion meeting took place at Norwich with the aim of establishing correlations of the Early and Middle Pleistocene stages across the southern North Sea. On the basis of faunal, floral, and palaeoclimatic data the following correlations were considered highly probable. The Pastonian Stage of East Anglia is correlated with the Late Tiglian (TC5) Stage of the Netherlands, and the Bramertonian with the Middle Tiglian (TC1-4b). The possibility that the British Antian and Bramertonian Stages may represent parts of a single climatic event is mentioned. The Ludhamian is probably of Early Tiglian age and the Pre-Ludhamian may equate in part with the Praetiglian Stage. Possible correlation of the Waltonian with part of the Pliocene Reuverian Stage is also suggested. In the later Middle Pleistocene, the Anglian Stage correlates with the continental Elsterian. The precise correlation of the British type Cromerian Stage with part of the ‘Cromerian Complex’ Stage in the Netherlands remains uncertain.

Pleistocene glacial limits in England, Scotland and Wales

This chapter reviews the evidence for glacial limits in England, Scotland, and Wales as understood at the beginning of 2002. Evidence for glaciation of England, Scotland, and Wales is primarily lithological with glacial episodes being identified by till and glaciofluvial sediments and glacial limits being determined by the extent of these deposits. Additionally, geomorphological evidence has played an important role in reconstructing the extent of ice masses in younger glaciations. Moraine ridges and ice-contact landforms, including patterns of glacio-isostatically deformed displaced shorelines, have played an important role in the determination of ice limits of these younger glacial events. Biological evidence has played a role in separating glacial events and in indicating a tendency toward climatic deterioration, or the existence of cold conditions that may be associated with glaciation. In the majority of cases, this biological evidence has taken the form of pollen, but molluska and plant macros have also been used to differentiate different stages of the Quaternary and insect faunas to provide direct evidence for the presence of glacial meltwater. Soil evidence, usually in the form of permafrost structures, has been used to indicate cold climate conditions that have been linked with the formation of glacier ice elsewhere in England, Wales, and Scotland.

The formation of the Strait of Dover

Abstract The Strait of Dover (Pas-de-Calais) is a narrow sea passage that links the North Sea and the English Channel between Britain and France. Much evidence suggests that the Dover Strait did not exist throughout most of the Pleistocene. Instead, a Chalk barrier was present, formed by the Weald-Artois anticline. Advance of the continental ice-sheet across the North Sea in the Middle Pleistocene Elsterian/Anglian Stage apparently dammed the southern part of the basin and water discharging into it was prevented from reaching the Atlantic to the north. The resulting lake apparently drained by spilling over the barrier and initiated the gap. This scenario is supported by sediments at Wissant, France. This theory contrasts with one, proposed by French geologists, that favours a structural origin. Overflow from the lake has been interpreted as having been catastrophic. This was invoked to explain the origin of the complex anastomosing system of valleys or channels that occurs on the floor of the Channel cut into bedrock, predominantly of Mesozoic age. These valleys are interlinked to form a drowned drainage system and can also be linked to present rivers that enter the Channel on both the British and French sides. However, it is highly probable that the drowned valley system is multigenetic, resulting from repeated fluvial and marine erosion and deposition rather than representing a single, short-lived event. The valley system probably originated in the late Early to early Middle Pleistocene as a consequence of uplift of the Weald-Artois region. Once the Dover Strait was formed, the rivers Thames and Scheldt were deflected through the gap and into the Channel River system during periods of low relative sea-level. Subsequently these rivers were probably joined by the Maas and Rhine, diverted by glaciation in the Drenthe Sub-stage (Saalian/Wolstonian Stage). The narrows seem to have been progressively enlarged by marine tidal scour and coastal erosion during high sea-level events.

The glacial history of the Pindus Mountains, Greece

Geomorphological evidence for Pleistocene glaciation has been mapped in the Pindus Mountains of northwest Greece, and the chronology of glaciation in this area has been established through soil profile analysis and U‐series dating of secondary carbonates (calcite) formed within glacial deposits. Three glacial stages are evident in the sedimentological and geomorphological records. The earliest and most extensive recorded glaciation predates 350,000 yr B.P. and was characterized by extensive valley glaciers and ice fields. A more recent glaciation occurred before the last interglacial and was characterized by glaciers that reached midvalley positions. The last phase of glaciation in Greece is recorded by small cirque glacier moraines and relict periglacial rock glaciers. The glacial and periglacial sequence on Mount Tymphi has been used in conjunction with a reference parastratotype, the long lacustrine sequence at Ioannina, to provide a chronostratigraphical framework for cold‐stage deposits in Greece. The three glacial stages are formally defined: the Skamnellian Stage, equivalent to the Elsterian Stage of northern Europe and marine isotope stage (MIS) 12; the Vlasian Stage, equivalent to the late Saalian Stage of northern Europe and MIS 6; and the Tymphian Stage, which is equivalent to the Weichselian/Würmian stages of northern Europe and the Alps, respectively, and MIS 5d‐2. This is the first formalized chronostratigraphical framework based on the glacial record to be established for cold stages in the Mediterranean and provides a new platform for paleoclimatological investigations in the region.

Periglacial fluvial systems in northwest Europe during marine isotope stages 4 and 3

Comparison of fluvial successions in river valleys dating from marine isotope (MI) Stages 4 and 3 in a west–east transect from Britain to Poland shows the spatial and temporal variation in palaeohydrological characteristics of northwest European river valleys during these stages. MI Stage 4 has been a period of deep fluvial incision. Following this erosion, most valleys were filled during MI Stage 3 with successions of gravelly river deposits (Britain) or sand/silt/peat successions (northwest European lowlands). The sedimentology of the deposits suggests strong discharge variations, caused by a nival discharge regime with pronounced spring snowmelt discharges. The MI Stage 3 climate oscillations generally cannot be traced in the fluvial record. An incision phase of Hengelo interstadial age has been found in the Netherlands, but similar incision phases related to other warming events have not been proved convincingly. The restricted reaction of the river systems is caused by the absence of geomorphologically effective vegetation changes and relatively minor variations in precipitation during MI Stage 3. Over longer time scales, silt and peat beds gradually decrease in the younger (post-Hengelo/Upton Warren) part of MI Stage 3, corresponding with evidence of aeolian activity and permafrost. This is related to the longer duration of the stadials in this part of MI Stage 3.

Extent and chronology of glaciations

Abstract The goal of the INQUA Commission on Glaciation Work Group 5 ‘Extent and Chronology of Glaciations’ was to assemble glacial chronologies from around the world to better understand ice sheet volumes and extents at various times, and to compile a GIS-supported database for past ice sheet extents. The project involved the contribution of over 200 scientists working in more than 80 countries and territories throughout the world. The resulting compilation represents the most complete survey of evidence of glaciation ever attempted. The results are published in the form of three volumes ‘Europe’, ‘North America’ and ‘South America, Asia, Africa, Australia, Antarctica’ (Quaternary Glaciations—Extent and Chronology, Part I: Europe, 2003a; Quaternary Glaciations—Extent and Chronology, Part II: North America, 2003b; Quaternary Glaciations—Extent and Chronology, Part III: South America, 2003c), each of which contain a series of maps in digital format accompanied by an explanatory text which includes discussion of the type and quality of data used.