Pollen Stratigraphy and Vegetation History, Sheguiandah Archaeological Site

2018 ◽  
pp. 179-194 ◽  
Author(s):  
T. W. Anderson
Keyword(s):  
Vegetation History ◽  
Archaeological Site ◽  
Pollen Stratigraphy

Vegetation history along the eastern, desert escarpment of the Sierra San Pedro Mártir, Baja California, Mexico

2011 ◽  
Vol 75 (3) ◽  
pp. 647-657 ◽  
Author(s):  
Camille A. Holmgren ◽  
Julio L. Betancourt ◽  
Kate A. Rylander
Keyword(s):  
Lake Sediments ◽  
Marine Sediments ◽  
Baja California ◽  
Vegetation History ◽  
Summer Rainfall ◽  
Plant Macrofossils ◽  
Eastern Desert ◽  
Pollen Stratigraphy ◽  
San Pedro ◽  
Sierra San Pedro Martir

AbstractPlant macrofossils from 38 packrat middens spanning the last ~ 33,000 cal yr BP record vegetation between ~ 650 and 900 m elevation along the eastern escarpment of the Sierra San Pedro Mártir, northern Baja California. The middens span most of the Holocene, with a gap between ~ 4600 and 1800 cal yr BP, but coverage in the Pleistocene is uneven with a larger hiatus between 23,100 and 14,400 cal yr BP. The midden flora is relatively stable from the Pleistocene to Holocene. Exceptions include Pinus californiarum, Juniperus californica and other chaparral elements that were most abundant > 23,100 cal yr BP and declined after 14,400 cal yr BP. Despite being near the chaparral/woodland-desertscrub ecotone during glacial times, the midden assemblages reflect none of the climatic reversals evident in the glacial or marine record, and this is corroborated by a nearby semi-continuous pollen stratigraphy from lake sediments. Regular appearance of C4 grasses and summer-flowering annuals since 13,600 cal yr BP indicates occurrence of summer rainfall equivalent to modern (JAS average of ~ 80–90 mm). This casts doubt on the claim, based on temperature proxies from marine sediments in the Guaymas Basin, that monsoonal development in the northern Gulf and Arizona was delayed until after 6200 cal yr BP.

The late-Quaternary vegetational history of the Western Interior of Canada

1976 ◽  
Vol 54 (15) ◽  
pp. 1793-1818 ◽  
Author(s):  
J. C. Ritchie
Keyword(s):  
Boreal Forest ◽  
Vegetation History ◽  
Deciduous Forest ◽  
Late Quaternary ◽  
The South ◽  
Southern Limit ◽  
Growing Seasons ◽  
Pollen Stratigraphy ◽  
Late Wisconsinan ◽  
Forest Boundary

The late-Wisconsinan pollen stratigraphy of the Western Interior of Canada is assembled and 16 representative sites provide a basis for establishing trends of vegetation history. Sites in the southern, prairie region show an early Picea–Artemisia assemblage (12 × 103 to 10 × 103) replaced by a zone dominated by herb pollen. Similarly, sites in the Aspen Parkland and Transitional zones all have the Picea–Artemisia zone from as early as 13.9 × 103 to 10 × 103, followed by a herb zone. It is replaced by an arboreal pollen zone at 4.5 × 103 to 3 × 103 B.P. While there is a broad trend common to all sites in the modern boreal forest, from an early spruce-dominated assemblage to a late postglacial spruce–pine–birch assemblage identical with modern spectra, there are differences in the details of stratigraphy. Two sites in central Alberta have a poplar zone preceding the early spruce zone. Sites near the modern southern forest boundary show a late development (3 × 103 B.P.) of the mixed boreal forest from prairie and hardwood deciduous forest communities. One site, at Flin Flon, Saskatchewan, provides clear evidence for a treeless episode (Artemisia–grass–sedge) preceding the spruce zone.As the late-Wisconsinan glacial ended, an early version of the boreal forest, dominated by spruce and lacking pine, spread from adjacent U.S. on to deglaciated surfaces and till over stagnant ice. It persisted in the southern part of the area until about 10 × 103 and until 6 × 103 in the northernmost portions. In the south the spruce forest was replaced directly by prairie, spreading from the southwest and extending farther north than its modern limit between 7.5 × 103 and 6 × 103. All remnants of ice sheets and glacial lakes had disappeared by about 7 × 103 and the northern part of the area was occupied by a boreal forest undergoing rapid changes in composition from the early spruce-dominated version to the mixed spruce–pine–birch–poplar mosaic prevalent today. Pine probably spread from western réfugia, at least into areas north and west of L. Winnipeg. At about 3 × 103 the southern limit of the forest extended to the south, apparently in response to a climate with cooler and (or) wetter growing seasons. The rapid replacement of the spruce-dominated boreal forest by grasslands in the early postglacial was probably a response to warmer and drier growing seasons.

23,000 yr of vegetation history of the Upper Lerma, a tropical high-altitude basin in Central Mexico

2005 ◽  
Vol 64 (1) ◽  
pp. 70-82 ◽  
Author(s):  
Socorro Lozano-GarcÍa ◽  
Susana Sosa-Nájera ◽  
Yoko Sugiura ◽  
Margarita Caballero
Keyword(s):  
Vegetation History ◽  
Population Expansion ◽  
Archaeological Site ◽  
Formative Period ◽  
Tree Cover ◽  
Central Mexico ◽  
Human Occupation ◽  
Arboreal Pollen ◽  
History Of ◽  
A Site

AbstractPollen analysis on a 9.54-m sediment core from lake Chignahuapan in the upper Lerma basin, the highest intermontane basin in Central Mexico (2570 m asl), documents vegetation and limnological changes over the past ∽23,000 14C yr. The core was drilled near the archaeological site of Santa Cruz Atizapán, a site with a long history of human occupation, abandoned at the end of the Epiclassic period (ca. 900 AD). Six radiocarbon AMS dates and two well-dated volcanic events, the Upper Toluca Pumice with an age of 11,600 14C yr B.P. and the Tres Cruces Tephra of 8500 14C yr B.P., provide the chronological framework for the lacustrine sequence. From ca. 23,000 14C yr B.P. to ca. 11,600 14C yr B.P. the plant communities were woodlands and grasslands based on the pollen data. The glacial advances MII-1 and MII-2 correlate with abundant non-arboreal pollen, mainly grasses, from ca. 21,000 to 16,000 14C yr B.P., and at ca. 12,600 14C yr B.P. During the late Pleistocene, lake Chignahuapan was a shallow freshwater lake with a phase of lower level between 19,000 and 16,000 14C yr B.P. After 10,000 14C yr B.P., tree cover in the area increased, and a more variable lake level is documented. Late Holocene (ca. 3100 14C yr B.P.) deforestation was concurrent with human population expansion at the beginning of the Formative period (1500 B.C.). Agriculture and manipulation of the lacustrine environment by human lakeshore populations appear at 1200 14C yr B.P. (550 A.D.) with the appearance of Zea mays pollen and abundant charcoal particles.

Biocultural Species Enhancement in the Archaeological Site of Tzintzuntzan, the “Place of Hummingbirds”

2019 ◽  
Vol 37 (3) ◽  
pp. 192-198
Author(s):  
Marina Barajas-Arroyo ◽  
Brenda Brown ◽  
José Luis Punzo ◽  
Jorge E. Schondube ◽  
Ian MacGregor-Fors ◽  
...  
Keyword(s):  
Archaeological Site

Mapping and Monitoring of the Land Use/Cover Changes in the Wider Area of ltanos, Crete, Using Very High Resolution EO Imagery With Specific Interest in Archaeological Sites

2019 ◽  
Author(s):  
Sawyer Reid stippa ◽  
George Petropoulos ◽  
Leonidas Toulios ◽  
Prashant K. Srivastava
Keyword(s):  
High Resolution ◽  
Spatial Resolution ◽  
Satellite Images ◽  
Archaeological Site ◽  
Digital Photography ◽  
Archaeological Sites ◽  
Large Area ◽  
High Resolution Imagery ◽  
Site Mapping ◽  
Rule Sets

Archaeological site mapping is important for both understanding the history as well as protecting them from excavation during the developmental activities. As archaeological sites generally spread over a large area, use of high spatial resolution remote sensing imagery is becoming increasingly applicable in the world. The main objective of this study was to map the land cover of the Itanos area of Crete and of its changes, with specific focus on the detection of the landscape’s archaeological features. Six satellite images were acquired from the Pleiades and WorldView-2 satellites over a period of 3 years. In addition, digital photography of two known archaeological sites was used for validation. An Object Based Image Analysis (OBIA) classification was subsequently developed using the five acquired satellite images. Two rule-sets were created, one using the standard four bands which both satellites have and another for the two WorldView-2 images their four extra bands included. Validation of the thematic maps produced from the classification scenarios confirmed a difference in accuracy amongst the five images. Comparing the results of a 4-band rule-set versus the 8-band showed a slight increase in classification accuracy using extra bands. The resultant classifications showed a good level of accuracy exceeding 70%. Yet, separating the archaeological sites from the open spaces with little or no vegetation proved challenging. This was mainly due to the high spectral similarity between rocks and the archaeological ruins. The satellite data spatial resolution allowed for the accuracy in defining larger archaeological sites, but still was a difficulty in distinguishing smaller areas of interest. The digital photography data provided a very good 3D representation for the archaeological sites, assisting as well in validating the satellite-derived classification maps. All in all, our study provided further evidence that use of high resolution imagery may allow for archaeological sites to be located, but only where they are of a suitable size archaeological features.

Sign in / Sign up

Export Citation Format

Share Document