Early Holocene Basinal Sediments of the Dakhleh Oasis Region, South Central Egypt

1989 ◽  
Vol 32 (2) ◽  
pp. 139-152 ◽  
Author(s):  
Ian A. Brookes
Keyword(s):  
Early Holocene ◽  
South Central ◽  
Sand Sheet ◽  
Record Variable ◽  
Ostrich Eggshell ◽  
Dakhleh Oasis

AbstractTwenty samples of artifactual ostrich eggshell and hearth charcoal, firmly to loosely associated with basinal lacustrine, playa, and sand sheet sediments in the Dakhleh Oasis region of south-central Egypt, yield radiocarbon ages between ca. 8800 and ca. 4700 yr B.P. The sediments record variable sedimentary responses to an early Holocene pluvial interval in this virtually rainless region. Differences of hydrogeology and morphometry among and within basin types complicate paleoclimatic interpretation.

scholarly journals Holocene biogeography of Tsuga mertensiana and other conifers in the Kenai Mountains and Prince William Sound, south-central Alaska

The Holocene ◽  
2016 ◽  
Vol 27 (4) ◽  
pp. 485-495 ◽  
Author(s):  
R Scott Anderson ◽  
Darrell S Kaufman ◽  
Edward Berg ◽  
Caleb Schiff ◽  
Thomas Daigle
Keyword(s):  
Climatic Factors ◽  
Tsuga Heterophylla ◽  
Picea Sitchensis ◽  
Early Holocene ◽  
Ice Age ◽  
Prince William Sound ◽  
Conifer Forest ◽  
The Holocene ◽  
South Central ◽  
Tsuga Mertensiana

Several important North American coastal conifers – having immigrated during the Holocene from the southeast – reach their northern and upper elevation limits in south-central Alaska. However, our understanding of the specific timing of migration has been incomplete. Here, we use two new pollen profiles from a coastal and a high-elevation site in the Eastern Kenai Peninsula–Prince William Sound region, along with other published pollen records, to investigate the Holocene biogeography and development history of the modern coastal Picea (spruce)– Tsuga (hemlock) forest. Tsuga mertensiana became established at Mica Lake (100 m elevation, near Prince William Sound) by 6000 cal. BP and at Goat Lake (550 m elevation in the Kenai Mountains) sometime after 3000 years ago. Tsuga heterophylla was the last major conifer to arrive in the region. Although driven partially by climate change, major vegetation changes during much of the Holocene are difficult to interpret exclusively in terms of climate, with periods of slow migration alternating with more rapid movement. T. mertensiana expanded slowly northeastward in the early Holocene, compared with Picea sitchensis or T. heterophylla. Difficulty of invading an already established conifer forest may account for this. We suggest that during the early Holocene, non-climatic factors as well as proximity to refugia, influenced rates of migration. Climate may have been more important after ~2600 cal. BP. Continued expansion of T. mertensiana at Goat Lake at the Medieval Climate Anomaly (MCA)–‘Little Ice Age’ (‘LIA’) transition suggests warm and wet winters. But expansion of T. mertensiana at both sites was arrested during the colder climate of the ‘LIA’. The decline was more extensive at Goat Lake, where climatic conditions may have been severe enough to reduce or eliminate the T. mertensiana population. T. mertensiana continued its expansion around Goat Lake after the ‘LIA’.

New excavations at the late Pleistocene site of Chinchihuapi I, Chile

2019 ◽  
Vol 92 (1) ◽  
pp. 70-80 ◽  
Author(s):  
Tom D. Dillehay ◽  
Carlos Ocampo ◽  
Jose Saavedra ◽  
Mario Pino ◽  
Linda Scott-Cummings ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Early Holocene ◽  
Occupied Site ◽  
Radiocarbon Dates ◽  
Central Chile ◽  
South Central ◽  
Cool Temperate ◽  
Human Use ◽  
Monte Verde ◽  
Point Type

AbstractThis paper presents new excavation data on the Chinchihuapi I (CH-I) locality within the Monte Verde site complex, located along Chinchihuapi Creek in the cool, temperate Valdivian rain forest of south-central Chile. The 2017 and 2018 archaeological excavations carried out in this open-air locality reveal further that CH-I is an intermittently occupied site dating from the Early Holocene (~10,000 cal yr BP) to the late Pleistocene (at least ~14,500 cal yr BP) and probably earlier. A new series of radiocarbon dates refines the chronology of human use of the site during this period. In this paper, we describe the archaeological and stratigraphic contexts of the recent excavations and analyze the recovered artifact assemblages. A fragmented Monte Verde II point type on an exotic quartz newly recovered from excavations at CH-I indicates that this biface design existed in at least two areas of the wider site complex ~14,500 cal yr BP. In addition, associated with the early Holocene component at CH-I are later Paijan-like points recovered with lithic tools and debris and other materials. We discuss the geographic distribution of diagnostic artifacts from the site and their probable relationship to other early sites in South America.

scholarly journals Soil Development as a Function of Time in the Rouge River Basin, South-Central Ontario

2007 ◽  
Vol 40 (2) ◽  
pp. 207-216 ◽  
Author(s):  
William C. Mahaney ◽  
Kalmia Sanmugadas
Keyword(s):  
River Basin ◽  
Soil Formation ◽  
Exchange Capacity ◽  
Early Holocene ◽  
Soil Thickness ◽  
South Central ◽  
Rouge River ◽  
Extractable Iron ◽  
Over Time ◽  
Changes In Soil Properties

ABSTRACT Three soils of postglacial age, representing a chronosequence in the Rouge River Basin of south-central Ontario, were studied to determine variations in morphological, physical, chemical, and mineralogical properties. These soils, forming in alluvium of mixed mineralogy represent the Late HoIocene (Entisol), Middle Holocene (lnceptisol),and Early Holocene (lnceptisol) surfaces. Horizon differentiation and soil thickness increase with greater age, while pH drops slightly in the sola of the older profiles. Cation exchange capacity (CEC) and organic matter in the surface horizons increases slightly with age, while, for the most part, CaCO3 and Ca/ Mg ratio decrease. Significant changes occur over time, especially with an increase of dithionite-extractable iron with age (from ~ 0.20 in the Late Holocene soil to ~ 0.70 in the Middle to Early Holocene profiles). Illite and illite-smectite tend to decrease with age, being replaced by small amounts of chlorite and vermiculite. In spite of some variability in parent materials due to stratification and preweathering, and minor changes in species composition, the changes in soil properties are attributed to processes of soil formation acting over time.

A Review of the Evidence for Early Holocene Turkeys in the Northern Great Basin

1977 ◽  
Vol 42 (1) ◽  
pp. 110-114 ◽  
Author(s):  
Donald K. Grayson
Keyword(s):  
Sexual Dimorphism ◽  
Great Basin ◽  
Significant Variation ◽  
Meleagris Gallopavo ◽  
Centrocercus Urophasianus ◽  
Early Holocene ◽  
Range Extension ◽  
Faunal Remains ◽  
Sage Grouse ◽  
South Central

Faunal remains recovered from the lower levels of the Connley Caves (south central Oregon) in the late 1960’s were attributed to turkey (Meleagris gallopavo), thus implying a major prehistoric range extension for this bird. Reanalysis of the Connley Caves avifauna demonstrates that this material should have been assigned to sage grouse (Centrocercus urophasianus), and that the original investigators erred by confusing sexual dimorphism with taxonomically significant variation.

The Upper Carboniferous Clifton Formation of northern New Brunswick: coal-bearing deposits of a semi-arid alluvial plain

1982 ◽  
Vol 19 (9) ◽  
pp. 1775-1785 ◽  
Author(s):  
Andrew S. Legun ◽  
Brian R. Rust
Keyword(s):  
New Brunswick ◽  
Central Africa ◽  
Plant Litter ◽  
Alluvial Plain ◽  
Common Source ◽  
Fine Grained ◽  
South Central ◽  
Okavango River ◽  
Sand Sheet ◽  
Semi Arid

Two contiguous successions within Member B of the Westphalian Clifton Formation are exposed on the coast of Chaleur Bay east of Bathurst, New Brunswick. The upper succession is dominated by sandstone, and the lower by shale, which encloses isolated channel and lenticular sandstone bodies. Distinctive features of the shale are thin coals, casts of tree trunks, calcareous paleosols, and deep desiccation cracks with calcareous coatings. Markov chain analysis of the shale-dominated succession defines a repetitive sequence of shale, rippled fine-grained sandstone, paleosol, and coal. This sequence is attributed to filling of flood basins followed by emergence and pedogenesis under semi-arid conditions, which prevented thick coal accumulation. The major sandstone bodies are interpreted as channels, associated with lenticular levee, crevasse-splay, or mouth-bar deposits of a semi-arid alluvial plain on which anastomosing channels dominated. The Okavango River of south-central Africa and Cooper's Creek in central Australia are proposed as modern analogues.The upper succession of Member B is characterized by sheet sandstones made up of top-truncated trough and planar cross-stratified units, with abundant plant litter and calcareous intraclasts. The rocks are interpreted as braided-fluvial sand sheet deposits that blanketed the lower succession floodplain. Petrographic and paleocurrent data suggest a common source for both successions. The progradation of the braided sand sheet may reflect a sedimentary response to climate change, tectonic rejuvenation, or a combination of both.

Palaeo-ecology and Pleistocene human occupation in south central Tasmania

Antiquity ◽  
1990 ◽  
Vol 64 (242) ◽  
pp. 59-78 ◽  
Author(s):  
Richard Cosgrove ◽  
Jim Allen ◽  
Brendan Marshall
Keyword(s):  
Late Pleistocene ◽  
Early Holocene ◽  
Human Settlement ◽  
Human Occupation ◽  
Faunal Assemblages ◽  
South Central

Evidence for the late-Pleistocene and early-Holocene settlement of Tasmania is now offered by a growing number of sites in a variety of landscapes; among the more remarkable finds are cave-sites with evidence for human settlement of periglacial uplands before 30,000 BP. Good faunal assemblages and environmental records allow the reconstruction of a subsistence system different in character from those modelled on a European Pleistocene prototype.

Biogeographic Implications of a Packrat Midden Sequence from the Sacramento Mountains, South-Central New Mexico

1984 ◽  
Vol 22 (3) ◽  
pp. 344-360 ◽  
Author(s):  
Thomas R. Van Devender ◽  
Julio L. Betancourt ◽  
Mark Wimberly
Keyword(s):  
New Mexico ◽  
Pinus Ponderosa ◽  
Late Holocene ◽  
Early Holocene ◽  
Desert Grassland ◽  
Creosote Bush ◽  
Oak Woodland ◽  
Middle Holocene ◽  
Sacramento Mountains ◽  
South Central

Thirteen packrat (Neotoma spp.) and two porcupine (Erethizon dorsatum) middens from 1555 to 1690 m elevation from the Sacramento Mountains, New Mexico, provide an 18,000-yr vegetation record in the northern Chiuahuan Desert. The vegetation sequence is a mesic, Wisconsin fullglacial (18,000–16,000 yr B.P.) pinyon-juniper-oak woodland; a xeric, early Holocene (ca. 11,000–8000 yr B.P.) juniper-oak woodland; a middle Holocene (ca. 8000-4000 yr B.P.) desert-grassland; and a late Holocene (ca. 4000 yr B.P. to present) Chihuahuan desertscrub. The frequency of spring freezes and summer droughts in the late Wisconsin probably set the northern limits of Pinus edulis and Juniperus monosperma at about 34°N, or 6° south of today's limit. Rising summer tempratures in the early Holocene eliminated pinyon and other mesic woodland plants from the desert lowlands and allowed the woodland to move upslope. At this time pinyon-juniper woodland and pine forest dominated by Pinus ponderosa probably began their spectacular Holocene expansions to the north. Continued warming in the middle Holocene led to very warm summers with strong monsoons, relatively dry, cold winters, and widespread desert-grasslands. Desertscrub communities in the northern Chihuahuan Desert did not develop until the late Holocene when the biseasonal rainfall shifted slightly back toward the winter, catastrophic winter freezes decreased, and droughts in all seasons increased. The creosote bush desertscrub corridor across the Continental Divide between the Chihuahuan and Sonoran deserts was probably connected for the first time since the last interglaciation.

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