Geoscience Reference
In-Depth Information
CHAPTER ONE
The physical
methods
The geology refers to the physical and chemical nature
of the solid rocks which underlie any part of Earth's
surface, together with associated structures such as faults
and folds. It includes also unconsolidated sediments at the
surface deposited by glaciers (till), rivers (alluvium) and
slope-processes (colluvium or head). The physiographic
evolution includes the present landforms of a region,
their morphology (i.e. shape and size) and the manner
in which they have been changed over time; the study
of physiographic evolution is thus both
spatial
(i.e. of
space) and
temporal
(i.e. of time). Climate and hydrology
include the pattern of climatic elements (e.g. insolation,
temperature, precipitation and wind) and the movement
of water on or in Earth's surface (i.e.
the hydrological
cycle
). Ecological and anthropogenic history donate two
influences of a biological nature; ecological
controls
focus
on soils, vegetation (
flora
)and animals (
fauna
), whilst
anthropogenic history includes the influences of human
beings on all parts of the physical landscape, both now and
in the past.
The geology plays a large part in forming this landscape
(
Figure 1.3
).
The rocks are horizontally bedded Upper
Palaeozoic Carboniferous limestones and sandstones
which have been deposited unconformably on Lower
Palaeozoic Ordovician and Silurian rocks, and on
Wensleydale Granite. The basal Carboniferous unit is
about 360 m thick and comprises a series of limestones,
the thickest being the Great Scar Limestone which
YORKSHIRE
Situated some 45 km north-west of the city of Leeds in
northern England lies the village of Grassington near the
river Wharfe. The Wharfe is one of a series of rivers rising
in the Pennine uplands of northern England and flowing
eastwards to the North Sea. Grassington forms a 'gateway'
to Upper Wharfedale, a 17 km steep-sided valley. Upper
Wharfedale has one prominent right-bank tributary, the
river Skirfare, occupying Littondale; other tributaries to the
river Wharfe are a series of short, steep-gradient streams
is one of the dales in the Yorkshire Dales National Park, and
is attractive to geographers and tourists alike (
Figure 1.1
).
The attraction of Upper Wharfedale for visitors, as in
all other dales in the National Park, lies in the unique
assemblage of environmental elements which interact
together to produce a landscape of great interest and
beauty.
Figure 1.2
shows how the four factors of (1)
geology, (2) physiographic evolution, (3) climate and
hydrology, and (4) ecological and anthropogenic history
work together in this dale. By the word
factor
is meant a
control
which produces an
effect
. In physical geography
it is recognized that these four controls act together in a
complex manner to produce the totality of the physical
environment. Another way of expressing this is to visualize
the four controls as
inputs
into the total landscape
system
.
