ENVIRONMENT
1. Human animal is part of the ECOSYSTEM i.e. the
natural world
i)
Environment governs human life
determine
vegetation
determines
animal life
|
All of this
determines how and where Humans live |
ii)
Sites must be viewed in their context/landscape
Must try to determine:
·
Geomorphological processes -changes in appearance of the land
·
Biological processes - changes in the plants and animals
2. Reconstruction of the Environment
3 questions:
i)
When? Need to determine the chronology of human activity against world
climatic successions e.g. Ice Age?
ii)
Vegetation? What was the vegetation
cover, evidence from pollen and other plant remains. Gives further evidence for
the climate.
iii) Fauna? What are the animal remains, including
microfauna? Often indicators of the microenvironment and specific
conditions at the site. Sometimes influenced by human activity e.g. structures,
erected for human comfort and survival, attracting particular microfauna.
Samples recovered often poorly preserved, so have to rely on best approximation
available.
3. Sources of Evidence
a) Oceans and Ice
Sheets
Deep sea cores, evidence from the sediments, e.g.
microfossils called foraminifera.
b) Ancient Winds
Isotope studies of Oxygen 16 and 18
enable
description of wind circulation and, therefore, climate. Winds have big impact
on human activity
c) Climatic Cycles
e.g. El Nino effect
d) Ancient Coastlines
Affected by climate, because determines quantity of
land available; silting up of rivers gives more land (Ephesus), coastal erosion
removes land (E.Yorkshire)
Ice Ages open up land bridges, as sea level drops,
e.g. Beringia (Bering Strait) 100k plain N/S 18000 years ago at glacial
maximum.
Ancient coastlines also affected by:
i) Isostatic uplift – land rises when
weight of ice is reduced as temperature rises
ii) Tectonic movements
–
displacement of plates in earth’s crust
iii) Volcanic eruptions
–
e.g. Pompeii, Thera
What were the effects of changing climate on the terrain itself?
Must reconstruct the local area with reference to:
a)
terrain
b)
water - permanent or periodic availability
c)
groundwater conditions
d)
susceptibility to flooding
EVIDENCE: from
a)
glaciated landscapes
·
U-shaped valleys
·
Polished and striated rocks
·
Moraine deposits
·
Glacial erratics (i.e. foreign rock brought in by the ice advance)
b)
Varves
·
periglacial phenomena, useful for dating (thin/thick layers deposited on
lake beds, telling of past climates)
·
important for palaeoclimatic information
·
limited use outside Scandinavia (need deep lakes)
c)
Rivers
·
What is the effect of flowing water on the landscape?
·
Often the focus of human occupation
·
Areas of rapid change (erosion/deposition of sediments)
·
N.B. Nile floodplains – irrigation agriculture – urban civilisation
·
Can change course if they do not cut deep channels e.g. Indus in
Pakistan, flooding and alluvial deposits
·
Meanders and ox-bow lakes
d)
Cave Sites
·
Less important than outdoor
·
Open sites are where people have spent most of their time
e)
Sediments and Soils
1.
Sediment: material deposited on the earth’s surface
2.
Soil: life-supporting, biologically and physically weathered upper layers of
these sediments
3.
Soil matrix: gives wealth of information on weathering, soil
types and land use
Site analysis: importance of
4.
Geomorphology: the study
of the form and development of the landscape, producing detailed analysis of
the
i)
composition and texture of sediments (from freely draining gravel and sand
to water-retentive clay)
ii)
size of constituent particles (from pebbles to sand and silt
iii)
extent of consolidation (from loose to cemented)
iv)
orientation of pebbles (indicating direction of stream flow, of slope or
glacial deposits)
·
Method: block sample from known context, consolidated first with resin,
thin section taken from it: polarising microscope reveals sequence of soil
development.
“Humans have affected soils and sediments at
a microscopic level”
e.g.
deforestation and intensive agriculture and farming, overgrazing (p237
illustration)
N.B 3 kinds of cultural
deposits:
a) Primary – e.g. those which accumulate on the surface, ash layers, floors etc
b)
Secondary – i.e. primary deposits which have undergone
modification
c)
Tertiary – i.e. those removed from original context,
reused elsewhere
Many human activities can now be recognised from their
micromorphological signals in soils and sediments
· Laboratory required
· Basic assessment in the field? Rubbing soil between fingers, plasticity in wetting? etc
· Munsell Soil Colour Charts – standardised descriptions of soil colour
Texture of soil?
· Series of sieves from 2mm to 0,06mm mesh sizes and
· Hydrometer (for determining density of liquids) or
· Thin section techniques
· Provides information on soil type, land use potential, susceptibility to erosion
· “lacquer” or paint-on synthetic latex technique – produces a peel-off film of sediment stratigraphy . Film stored flat or rolled up….
6. Loess Sediments
Pedologist (soil specialist) can say how sediment was deposited: whether by
·
Water
·
Wind or
·
Human action
Loess – wind–blown sediment, yellowish dust, silt sized particles, covers about 10% of land surface
·
Important
indicator of ancient climate
·
esp. associated with first agricultural
settlements of the Neolithic, fertile, easily worked soils
·
only deposited
when relatively cold, dry climate, blown off steppe-like landscape, “rained”
down and held by warmer and wetter
areas (Sahara dust?)
7. Buried Land Surfaces
·
Preserved
intact by e.g. volcanic eruption. Pompeii, Herculaneum
