Middle Holocene Deposits Research Articles

Multi-proxy paleoenvironmental data from Paulina Marsh inform human-environmental dynamics in the Northern Great Basin U.S.A.

Understanding the dynamics between climate change and human adaptive strategies is a longstanding question driving paleoecological and archaeological research in North America's Great Basin. We present multiproxy data from five sediment cores retrieved from Paulina Marsh in the Fort Rock Basin, Oregon, an area renowned for its archaeology but lacking the paleoenvironmental data needed to fully contextualize those records. Radiocarbon, pollen, particle size, elemental, and charcoal analyses of one core, and geochronological data from four additional cores, reveal fluctuating vegetation communities, hydrologic conditions, and fire histories during the Early and Late Holocene that are consistent with models proposed to explain changing settlement-subsistence patterns in the region. There was likely an emergent marsh or meadow and an absence of Juniperus at the core site during the Early Holocene. Middle Holocene deposits are not present due to a geologic unconformity, perhaps because of channel migration and climatic aridity. Late Holocene sediments record a more mesic meandering stream system between ∼3900 and 2200 years ago, followed by an increase in xeric-adapted vegetation in the last 2000 years. The lack of Juniperus pollen in the Early Holocene sediments inform ongoing debates about Juniperus spread in the Great Basin. These data represent the first Early Holocene pollen record from the Fort Rock Basin and are one of few lowland vegetation histories of this age in the region. This study contributes to our understanding of past ecology in semi-arid environments, provides new context for archaeological interpretations, and establishes a framework for future work in the region.

Earliest record of the spinose ear tick, Otobius megnini (Dugès) (Ixodida: Argasidae), from the Paisley Caves site (Oregon, USA), with implications for prehistoric human ectoparasitism

The discovery of five individual specimens of the spinose ear tick, Otobius megnini (Dugès), in late Pleistocene through middle Holocene deposits of the Paisley Caves site highlights an interesting aspect of prehistoric life not ordinarily visible through the analysis of traditional archaeological artifacts. A review of the literature provides ample evidence to postulate how the tick remains got into the cave deposits, and also implies the possibility of host-switching behavior in this tick and explores the manner by which ancient people dealt with ectoparasites. Furthermore, these remains mark the first record of the species in both archaeological and paleontological contexts.

Stelladinium bifurcatum n. sp., a distinctive extant thermophilic heterotrophic dinoflagellate cyst from the late Quaternary of the eastern Pacific and east equatorial Atlantic oceans

Stelladinium bifurcatum n. sp. is a large and distinctive brown heterotrophic dinoflagellate cyst recorded from Upper Pleistocene through modern sediments of the eastern Pacific, modern sediments of the western Bay of Bengal and sediment traps from the South China Sea, and Upper Pleistocene through Middle Holocene deposits of the east equatorial Atlantic. It is distinguished by prominent apical and antapical horns, numerous long processes distributed along the cingulum, tips of horns and processes that are characteristically solid or thickened and taper to points, a prominent flagellar scar, and an archeopyle formed by the second anterior intercalary plate with the operculum adnate along the right lateral margin. Stelladinium bifurcatum has been recorded in the literature under several names including “ Stelladinium reidii ” and the cyst of Protoperidinium stellatum from which it differs in having abundant cingular processes, at least one of which usually has a strongly divergent bifurcation. Re-examination of published records shows Stelladinium bifurcatum to have a tropical–subtropical neritic distribution in modern sediments of the eastern Pacific margin and to be associated with high biological productivity. Similarly in Pleistocene–Holocene sediments off west equatorial Africa, Stelladinium bifurcatum is linked to elevated sea-surface temperatures during the last deglaciation, and it serves as a marker of river discharge associated with an increase in monsoonal dynamics at this time. • The distinctive new dinoflagellate cyst Stelladinium bifurcatum n. sp. is described. • It has a tropical–subtropical modern neritic distribution associated with high biological productivity. • In Pleistocene–Holocene sediments off west equatorial Africa, Stelladinium bifurcatum serves as a marker of river discharge. • Stelladinium bifurcatum sp. nov. has a lowest known stratigraphic occurrence in the Upper Pleistocene.

Early- and middle-Holocene wood exploitation in the Fayum basin, Egypt

The early and middle Holocene of North Africa was a time of dramatic climatic and social change, including rapid shifts in vegetation communities and the introduction of domesticated plants and animals. Recent research from the Fayum basin of Egypt, which holds archaeological evidence for early use of domesticates, aims to place inhabitants of that region within their contemporary environmental setting. We present here results of wood charcoal analysis from three early- and middle-Holocene deposits on the north shore of the Fayum and reconstruct both contemporary woodland ecology and patterns of anthropogenic wood use. In total, three woodland communities likely existed in the area, but inhabitants of this region made heavy use of only the local lakeshore woodland, emphasizing tamarisk ( Tamarix sp.) for fuel. While seasonally watered wadi woodlands were not harvested for fuel, more arid locations on the landscape were, evidencing regional mobility between ecological zones. Results indicate that wood was locally abundant and that inhabitants were able to select only preferred species for fuel. This study provides further evidence for low-level food production in the Fayum that preserved critical ecosystem services, rather than dramatic niche construction to promote agriculture as seen elsewhere in middle-Holocene Southwest Asia.

Paleoenvironment in East Java during the last 25,000 years as inferred from bovid and cervid dental wear analyses

This paper reports the results of dental mesowear and microwear analyses of bovid and cervid specimens recovered from Late Pleistocene to Middle Holocene deposits of Braholo Cave and Song Terus in Eastern Java. The aim is to infer ungulate dietary traits from dental wear signatures and gain insights regarding the paleoenvironment of the region during the last 25,000years, a period of drastic climatic fluctuations. We considered three cervid (Rusa, Axis and Muntiacus muntjak) and two bovid (Bubalus and Bos javanicus) taxa in the analyses. Results from both cave sites suggest that the Pleistocene-Holocene transition was accompanied by expansion of rainforests as evidenced by the predominance of species that had a browsing or browse-dominated mixed diet. However some of the taxa examined exhibited strong grazing signatures indicative of the continued presence of patches of grasslands up to the Mid-Holocene. Dental wear signatures of specimens from layers dating to the Last Glacial Maximum (LGM) suggest a mosaic environment dominated by grasslands. In Braholo Cave, we observed discrepancies between the mesowear and microwear signatures in specimens dating to the LGM and we take this as evidence of seasonality during this period. The results of the study provide important information on the environments encountered by the hunter-gatherer communities that lived in East Java in periods of climatic change.

Late Pleistocene-Holocene amphibians from Okinawajima Island in the Ryukyu Archipelago, Japan: Reconfirmed faunal endemicity and the Holocene range collapse of forest-dwelling species

Amphibian fossils excavated from two Late Pleistocene-Holocene fissures in the southern part of Okinawajima Island in the Ryukyu Archipelago were identified through detailed comparisons with skeletal specimens of extant taxa. The identified species (eight frogs and two newts) were confined to extant elements on the island and were mostly endemic to either the island or the central part of the archipelago including it. Previous Late Pleistocene records of extralimital frogs (two mainland Japanese species [Glandirana rugosa and Rana tagoi] and one Southeast Asian frog currently naturalized in the Ryukyus [Polypedates leucomystax]) from one of the study sites (the Minatogawa Fissure) are therefore considered misidentifications. This may also be the case with Fejervarya kawamurai, a synanthropic frog currently widely distributed in East Asia, including the Central Ryukyus. Of the species obtained from the Late Pleistocene deposits at these sites, five frogs (Limnonectes namiyei, Babina holsti, Odorrana ishikawae, O. narina, and Rana ulma) are forest-dwellers currently confined to the northern forested area of Okinawajima. Additionally, none of these species were detected in the middle Holocene deposits from one of the sites, the Sashiki Fissure. Our findings indicate that the southern limestone area of Okinawajima in the Late Pleistocene harbored a dense and humid forest with diverse lotic habitats, similar to the northern forested area of the island at present, and that these environmental conditions were lost by the midpoint of the Holocene Period.

Stratigraphy and paleoenvironments of the early to middle Holocene Chipalamawamba Beds (Malawi Basin, Africa)

Abstract. We describe the Chipalamawamba Beds, early to middle Holocene deposits at the southern margin of long-lived Lake Malawi. The beds are exposed because of downcutting of the upper Shire River. The Chipalamawamba sediments are medium to coarse, yellow to brown sands deposited in lenses varying in horizontal extent from a few meters to several hundreds of meters. Four units are recognized; the first three mainly contain lacustrine sediments deposited during lake high stands about 10.6–9.7 cal ka BP (Unit 1), 7.6–6.5 cal ka BP (Unit 2) and 5.9–5.3 cal ka BP (Unit 3). Sediments of Unit 4 overlay Units 1 to 3, are coarser and display regular foresets and oblique-bedding, suggesting deposition in riverine environments after installation of the Shire River (~ 5.5–5.0 ka BP). Freshwater mollusk assemblages and bioturbation regularly occur in the lacustrine sediments, but are largely absent from Unit 4. Diverse and often contradicting hypotheses on the lake levels of Lake Malawi have been proposed for the early and middle Holocene. The Chipalamawamba Beds allow straightforward recognition of water levels and provide strong evidence for oscillating lake levels during this period, rather than continuous high or low levels. Sedimentation rates have been high and individual shell beds have typically been deposited during a few decades. Because the Chipalamawamba Beds contain a sequence of mollusk assemblages with intervals between subsequent shell beds ranging from a century to a few millennia, they enable paleontological analysis of the fauna with an unusually high temporal resolution. That some mollusk lineages inhabiting Lake Malawi are in the early stages of diversification and radiation increases the paleobiological relevance of these beds.

Stratigraphy and geochronology of upper Quaternary eolian sand on the Southern High Plains of Texas and New Mexico, United States

Eolian sand in dune fields and sand sheets cover >10 000 km 2 (∼10%) of the Southern High Plains of northwestern Texas and eastern New Mexico. These deposits are concentrated in three west-east–trending belts of dunes (the Muleshoe, Lea-Yoakum, and Andrews dune fields, from north to south) that appear to be eastern extensions of the Mescalero-Monahans dune system in the Pecos River valley, and in the Seminole sand sheet, a discontinuous accumulation of sheet sands between the Lea-Yoakum and Monahans-Andrews dunes. The most common landforms are parabolic dunes associated with blowouts, coppice dunes, and sand sheets, all typical of sandy, vegetated, semiarid landscapes, barchan dunes, in keeping with a relatively limited sand supply and an underlying surface that is relatively hard (Blackwater Draw Formation, Pleistocene), and fence-row dunes, historic dunes formed along field boundaries. These eolian deposits accumulated episodically in the late Pleistocene and Holocene and provide clues to the history of regional drought and aridity. The earliest phase of sedimentation occurred when sheet sands were deposited between 11 000 and 8000 14 C yr B.P., probably in several phases, based on archaeological data, as a result of episodic drought beginning between 11 000 and 10 000 yr B.P. Eolian deposits dating between 8000 and 3000 yr B.P. are rare, although eolian sediment 8000–4500 14 C yr B.P. is ubiquitous in the draws that cross the region, and paleoenvironmental indicators show that the region was subjected to aridity throughout middle Holocene time. The middle Holocene deposits most likely were remobilized in late Holocene time. Most of the deposits and landforms of the dune fields and sand sheets are late Holocene, dating before 4000 14 C yr B.P. and mostly before 1500 14 C yr B.P. The Muleshoe and Lea-Yoakum dunes and the Seminole sand sheet underwent substantial eastward expansion in late Holocene time. Buried soils and radiocarbon ages show that the eolian sand accumulated in several stages, probably in response to cyclic drought. The Muleshoe dunes accumulated after ca. 1300 cal yr B.P. (ca. 1400 14 C yr B.P.), after ca. 750–670 cal yr B.P. (ca. 850–750 14 C yr B.P.), just after ca. 500 cal yr B.P. (ca. 450 14 C yr B.P.), and during the nineteenth and twentieth centuries. The Lea-Yoakum dunes were active after ca. 3400 cal yr B.P. (ca. 3200 14 C yr B.P.) and historically. The Seminole sand sheet was active ca. 430–330 cal yr B.P. (ca. 360 14 C yr B.P.) and in the twentieth century. The Andrews dunes were subjected to at least two phases of eolian sedimentation after ca. 2320 cal yr B.P. (ca. 2320 14 C yr B.P.). Comparisons with eolian chronologies from other regions on the Great Plains suggest that dune mobilization was a regional phenomenon after ca. 2300 cal yr B.P. (ca. 2300 14 C yr B.P.); after ca. 1500–1400 cal yr B.P. (ca. 1650–1550 14 C yr B.P.); after ca. 700 cal yr B.P. (ca. 800 14 C yr B.P.); between 500 and 300 cal yr B.P. (ca. 450–300 14 C yr B.P.); and in the nineteenth century. The climatic fluctuations responsible for mobilizing the dunes probably were relatively minor, yet the landscape impacts were substantial, resulting in widespread wind erosion and dune construction.

Palaeoenvironmental research on diatoms in early and middle Holocene deposits in central North Holland (The Netherlands)

In the geological research of the Holocene coastal deposits of The Netherlands, diatoms are used to reconstruct the sedimentary facies, palaeo-tide levels and salinity gradients during the deposition of the sediments. In this paper, the results of diatom research from 4 borings, taken from the early and middle Holocene deposits of central North Holland are presented. The oldest marine influenced sediments in the area are the deposits of the ‘Velsen layer’, a clay layer rich in organic matter and deposited about 8000–700014C years before present (BP) at a depth of 20–12 m below present mean sea-level. This clay layer was formed in a shallow, permanently submerged environment with a limited tidal influence (lagoonal or pond-like conditions). The salinity changed from brackish/freshwater to marine/brackish. The younger sandy and clayey sediments, formed about 7000–4500 BP at a depth of 16–3 m below present mean sea-level, are classified as ‘tidal channel’ and ‘interchannel’ deposits. It is argued, on the base of both diatom and non-diatom criteria, that the lower and middle parts of the interchannel deposits in the central area of the palaeo-tidal basin of North Holland were formed in a subtidal environment. The upper part of the interchannel deposits and the deposits at the fringe of the North Holland tidal basin were formed in the intertidal zone or, at the fringe of the basin, even in the supratidal zone. The salinity in the North Holland tidal basin during the sedimentation of the tidal channel and interchannel deposits was marine/brackish to marine. This study indicates that diatoms, besides their palaeoecological applications, have chronostratigraphical significance (on a regional scale). The diatomsCymatosira belgica andActinoptychus splendens appear to be a useful (eco)stratigraphical marker in the Holocene coastal deposits of The Netherlands and Belgium.