7 Sedimentation and tectonics at a mid-Ordovician to Silurian active margin

The document attached below includes the seventh section of Mountain building in Scotland. In this section, you will find the following subsections:

• 7.1 Introduction

• 7.2 Mid-Ordovician to Silurian sedimentation in the Midland Valley Terrane

  • 7.2.1 Ordivician sedimentation

  • 7.2.2 Silurian sedimentiation

  • 7.2.3 Summary of Section 7.2

• 7
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Learning outcomes

When you have studied this unit you should be able to:

• describe the geological history of the Scottish Highlands;

• give examples of igneous, metamorphic and structurally complex rocks.

11.5 Summary of sections 8 to 11

In these sections we have described some of the quantitative relationships between the physical dimensions of simple sounds and their subjective psychological dimensions. The physical dimension of intensity, or pressure amplitude, given in decibels (dB), directly affects loudness. Frequency of pressure changes, in hertz (Hz), mainly determines pitch.

The lowest threshold value and hence the maximal sensitivity for humans is in the region of 3000 Hz.

The quantitative relationship b
Author(s): The Open University

11.3 Frequency selectivity

In preceding sections we examined two ways in which the auditory system may code frequency information: the place theory and phase locking. In this section we will look at the psychophysical evidence for place coding on the basilar membrane by examining the ability of the auditory system to resolve the components of sinusoidal waves in a complex sound – a phenomenon known as frequency selectivity.

The perception of a sound depends not only on its own frequency and intensity but also o
Author(s): The Open University

9.1 Introduction

Psychophysics is the oldest field of the science of psychology. It stems from attempts in the nineteenth century to measure and quantify sensation. It attempts to quantify the relationship between a stimulus and the sensation it evokes, usually for the purpose of understanding the process of perception. Historically, psychophysics has centred around three general approaches. The first involves measuring the smallest value of some stimulus that a listener can detect – a measure of sensitivit
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7.2 Coding of information in the higher auditory centres

We have seen that in the cochlear nerve, information about sound intensity is coded for in two ways: the firing rates of neurons and the number of neurons active. These two mechanisms of coding signal intensity are found throughout the auditory pathway and are believed to be the neural correlates of perceived loudness. The tonotopic organisation of the auditory nerve is also preserved throughout the auditory pathway; there are tonotopic maps within each of the auditory nerve relay nuclei, the
Author(s): The Open University

3.5.2 Mechanical force directly opens and closes transduction channels

It is believed that tip links aid in causing ‘channels’ to open and close near the top of the hair cell (Figure 16). Tip links are filamentous connections between two stereocilia. Each tip link is a fine fibre obliquely joining the distal end of one stereocilium to the side of the longest adjacent process. It is thought that each l
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3.2 The anatomy of the cochlea

The cochlea has a spiral shape resembling the shell of a snail (Figure 4a). You can approximate the structure of the cochlea by wrapping a drinking straw 2.5 times around the tip of a sharpened pencil. The hollow tube, represented by the straw, has walls made of bone and the central pillar of the cochlea, represented by the pencil, is a conical
Author(s): The Open University

3.1 Introduction

The inner ear (Figure 3) can be divided into three parts: the semicircular canals, the vestibule and the cochlea, all of which are located in the temporal bone. The semicircular canals and the vestibule affect the sense of balance and are not concerned with hearing. However, the cochlea, and what goes on inside it, provides
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1 Sound reception: the ear

In order to hear a sound, the auditory system must accomplish three basic tasks. First it must deliver the acoustic stimulus to the receptors; second, it must transduce the stimulus from pressure changes into electrical signals; and third, it must process these electrical signals so that they can efficiently indicate the qualities of the sound source such as pitch, loudness and location. How the auditory system accomplishes these tasks is the subject of much of the rest of this block. We will
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2.5.1 Quantum mechanics and chance

The real quantum revolution dates from the formulation of quantum mechanics by Werner Heisenberg (1901–1976) and others in 1925, and its physical interpretation by Max Born (1882–1970) in 1926. However, before attempting even the most basic sketch of quantum mechanics let's take a small diversion into the realm of philosophy.

The basic working philosophy of most scientists, including those who say they have no philosophy, is a kind of realism. (Philosophers recognise m
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2.3.2 Equilibrium and irreversibility

As the science of thermodynamics developed beyond its industrial roots, two powerful ideas came to the fore – equilibrium and irreversibility. These ideas were already implicit in studies of heat. You have already seen that heat flow from a hot steak to a cold plate is an irreversible process. The effect of this process is to cool down the hot steak and warm up the cold plate, leading to a more uniform distribution of temperature. The heat transfer continues until a state of e
Author(s): The Open University

5.2.1 The GM Science Review

The review was undertaken by the GM Science Review Panel, chaired by the Government's Chief Scientific Adviser, Sir David King. Its role was to assess the evidence available in the peer-reviewed scientific literature. The panel produced two reports, the first in July 2003 and the second in January 2004. The main conclusions of these reports are listed below.

• The risk to human health is very low.

• There is little likelihood of such plan
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4.4 Incorporating substantial equivalence into national and international law

The concept of substantial equivalence very quickly became important in international trade law. The WTO aims to harmonise national food standards to meet international norms. Under its rules, a country could be penalised if it imposed food standards more stringent than those agreed internationally. In this context, international food standards are set by the Codex Alimentarius Commission (Table 1). In 1996, a report was issued within the Codex framework, which endorsed the principle of subst
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4.2 Scientific risk analysis

In the context of national and international legislation on the safety of food and animal feed, much of the thinking about assessing risk has come from the experience of developing legislation to cover potentially toxic chemicals. In this regard, the terms ‘risk’ and ‘hazard’ are particularly important. ENTRANSFOOD (European network safety assessment of genetically modified food crops) has defined the terms as follows:

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