ENVIRONMENT

 

1.   Human animal is part of the ECOSYSTEM i.e. the natural world

 

i)      Environment governs human life

 

Latitude  Altitude  Climate

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

 


 

STUDYING THE LANDSCAPE

 

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)

 

5.    Soil micromorphology:  the use of microscopic techniques to study the nature and organisation of the components of soil.

·        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