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1、环境地质学Environmental Geology主讲人：主讲人：万新南万新南教授教授Prof. Wan xinnan环境地质学环境地质学环境地质学环境地质学 Environmental Geology2 2、时空中的地球、时空中的地球 Earth in Space and Time 1）早期的太阳系）早期的太阳系 The Early Solar System Billions of years ago, out of a swirling mass of gas and dust, evolved a system of varied planets hurtling around a n
2、uclear-powered star-our solar system. One of these planets, and one only, give rise to complex life forms. Over time, a tremendous diversity of life forms and ecological system developed, while the planet too evolved and changed, its interior churning搅拌, its landmasses shifting漂移, its surface consta
3、ntly being reshaped 环境地质学环境地质学环境地质学环境地质学 Environmental Geology2 2、时空中的地球、时空中的地球 Earth in Space and Time 1）、早期的太阳系）、早期的太阳系 The Early Solar System Billions of years ago, out of a swirling mass of gas and dust, evolved a system of varied planets hurtling around a nuclear-powered star-our solar system.
4、One of these planets, and one only, give rise to complex life forms. Over time, a tremendous diversity of life forms and ecological system developed, while the planet too evolved and changed, its interior churning搅拌, its landmasses shifting漂移, its surface constantly being reshaped 环境地质学环境地质学环境地质学环境地
5、质学 Environmental Geology2 2、时空中的地球、时空中的地球 Earth in Space and Time 2）九大行星的形成九大行星的形成The planets The compositions of the planets formed depended largely on how near they were to the hot sun. The planets formed nearest to the sun contained mainly high-temperature materials: metallic iron and a few miner
6、als with very high melting temperatures, with little water or gas. Somewhat farther out, where temperatures were lower, the developing planets incorporated much larger amounts of lower-temperature minerals, including some that contain water locked within their crystal structures. (This development l
7、ater made it possible for the earth to have liquid water at its surface.) Still farther from the sun, temperatures were so low that nearly all of the materials in the original gas cloud condensedeven materials like methane and ammonia, which are gases at normal earth surface temperatures and pressur
8、es. 环境地质学环境地质学环境地质学环境地质学 Environmental Geology2 2、时空中的地球、时空中的地球 Earth in Space and Time 3、地球与其它星体的比较环境地质学环境地质学环境地质学环境地质学 Environmental Geology2 2、时空中的地球、时空中的地球 Earth in Space and Time 4）、地球的结构与组成环境地质学环境地质学环境地质学环境地质学 Environmental Geology4 4）地球的构造与组成地球的构造与组成 2、时空中的地球时空中的地球 Earth in Space and Time环境地质
9、学环境地质学环境地质学环境地质学 Environmental Geology5 5）地球的演化地球的演化 Earth, then and now A、(地球的初始无序形态：无海洋、无大气）地球的初始无序形态：无海洋、无大气） The early earth was very different from what it is today, lacking the modern oceans and atmosphere and having a much different surface from its present one, probably more closely resembli
10、ng the barren, cratered surface of the moon. The planet was heated by several processes: the impact of the colliding dust particles and meteorites as they came together to form the earth, compression of the interior by gravity (that materials heat up when compressed can be demonstrated by pumping up
11、 a bicycle tire and then feeling the barrel of the pump), and energy release from decay of the small amounts of several naturally radioactive elements that the earth contains. 环境地质学环境地质学环境地质学环境地质学 Environmental Geology5 5）地球的演化地球的演化 Earth, then and now B、(地球的初始无序形态三类热源、使之熔化、分异）地球的初始无序形态三类热源、使之熔化、分异）
12、 These three heat sources combined to raise the earths internal temperature enough that parts of it, perhaps eventually most of it, melted, although it was probably never molten all at once. Dense materials, like metallic iron, would have tended to sink toward the middle of the earth. As cooling pro
13、gressed, lighter, low-density mineral crystallized and floated out toward the surface. The eventual result was an earth differentiated into several major compositional zones; the central core; the surrounding mantle; and a thin crust at the surface (fig1.1.1). The process was complete before 4 billi
14、on years ago.（四十亿年前） 环境地质学环境地质学环境地质学环境地质学 Environmental Geology5 5）地球的演化地球的演化 Earth, then and now C、早期大气层的形成（早期大气层的形成（The earths early atmosphereThe earths early atmosphere） quite different from the modern one, aside from the effects of modern pollution. （1）、（无大气层、缺氧）The first atmosphere had little
15、or no free oxygen in it. It probably consisted dominantly of nitrogen and carbon dioxide ( the gas most commonly released from volcanoes, aside from water) with minor amounts of such gases as methane, ammonia, and various sulfur gases. （2）、（人类不能生存）Humans could not have survived in this early atmosph
16、ere. （3）、（藻类造氧说）Oxygen-breathing life of any kind could not exist before the first simple plants-the single-celled blue-green algae藻-appeared in large numbers to modify the atmosphere. Their remains are found in rocks several billion years old. They manufacture food by photosynthesis, using sunlight
17、 for energy, consuming carbon dioxide, and releasing oxygen as a by-product. In time, enough oxygen accumulated that the atmosphere could support oxygen-breathing organisms. 环境地质学环境地质学环境地质学环境地质学 Environmental Geology5 5）地球的演化地球的演化 Earth, then and nowD D、地球与地球表面岩石年龄的确定、地球与地球表面岩石年龄的确定（1）、Arranging Eve
18、nts in Order （事件排序法）（2）、）、Correlation Fossils play a role in the determination or relative ages, too. The concept that fossils could be the remains of older life forms dates back at least to the ancient Greeks, but for some time it fell out of favor不再、失去. The idea was seriously revived复苏 in the 1700
19、s, and around the year 1800, William Smith put forth the Law of Faunal Succession（生物层序法）. (3)、Uniformitarianism Geologic processes were the focus of another early worker-the physician, farmer, and part-time geologist James Hutton. Hutton is widely credited with developing and popularizing the concep
20、t of uniformitarianism均变说. Uniformitarianism is sometimes described briefly by the phrase“the present is the key to the past.” （均变说）环境地质学环境地质学环境地质学环境地质学 Environmental Geology5 5）地球的演化地球的演化 Earth, then and nowD D、地球与地球表面岩石年龄的确定、地球与地球表面岩石年龄的确定（4）、 Radioactive Decay and DatingAs noted above, one key pr
21、operty of any particular radioisotope is that it decays at a constant, characteristic rate, with a distinct half-life, which can be determined in the laboratory. One can then, in principle, use the relative amounts of a decaying isotope (parent) and the product isotope into which it decays (daughter
22、) to find the age of the sample. Fig.A.7 illustrates the fundamental idea. Suppose that parent isotope A decays to daughter B with a half-life of 1 million years. （放射性测年）（放射性测年）（5）、Radiometric and Relative Ages Combined Radiometric dates放射性测年 (dates determined using radioisotopic methods) are someti
23、mes imprecisely called “absolute” ages to distinguish them from the relative ages determined as described earlier. For various reasons, accurate radiometric dates cannot be determined for many rocks and fossils, so “absolute” and relative dating methods are often used in conjunction. （放射性测年与相对年龄法结合）
24、（放射性测年与相对年龄法结合）环境地质学环境地质学环境地质学环境地质学 Environmental GeologyE、地质时代表、地质时代表 Geologic time 5）地球的演化地球的演化 Earth, then and now环境地质学环境地质学环境地质学环境地质学 Environmental Geology4 4）地球上的生物演化地球上的生物演化Earth, then and now 环境地质学环境地质学环境地质学环境地质学 Environmental Geology3、人口、人口Nature and Rate of Population Growth Growth Rates: C
25、auses and Consequences Growth Rate and Doubling Time 环境地质学环境地质学环境地质学环境地质学 Environmental Geology3、人口、人口Nature and Rate of Population Growth 世界总人口与人口分布 亚洲与中国人口环境地质学环境地质学环境地质学环境地质学 Environmental Geology3、人口、人口Nature and Rate of Population Growth 环境地质学环境地质学环境地质学环境地质学 Environmental Geology4、地球物质的化学组成Rock
26、 and Minerals in earth Atomic Structure All natural and most synthetic substances on earth are made from the ninety naturally occurring chemical elements. An atom is the smallest particle into which an element can be divided while still retaining the chemical characteristics of that element (fig 3.1
27、). The nucleus, at the center of the atom, contains one or more particles with a positive electrical charge (protons质子) and usually some particles of similar mass that have no charge (neutrons中子). Circling the nucleus核 are the negatively charged electrons.环境地质学环境地质学环境地质学环境地质学 Environmental Geology4、
28、地球物质的化学组成Rock and Minerals in earth 环境地质学环境地质学环境地质学环境地质学 Environmental Geology4、地球物质的化学组成Rock and Minerals in earth Elements and Isotopes4.With the exception of the simplest hydrogen atoms, all nuclei contain neutrons, and the number of neutrons is similar to or somewhat greater than the number of p
29、rotons. The number of neutrons in atoms of one element is not always the same. The sum of the number of protons and the number of neutrons in a nucleus is the atoms atomic mass number. Atoms of a given element with different atomic mass numbersin other words, with the same number of protons but diff
30、erent numbers of neutronsare distinct isotopes of that element. Some elements have only a single isotope, while others may have ten or more. (The 环境地质学环境地质学环境地质学环境地质学 Environmental Geology4、地球物质的化学组成Rock and Minerals in earth Chemical Symbols8. Each chemical element is denoted by a one-or two-letter
31、 symbol. Many of these symbols make sense in terms of the English name for the element-O for oxygen, He for helium, Si for silicon, and so on. Other symbols reflect the fact that, in earlier centuries, scientists were generally versed in Latin or Greek: The symbols Fe for iron and Pb for lead, for e
32、xample, and derived from ferrum and plumbum, respectively, the Latin names for these elements.环境地质学环境地质学环境地质学环境地质学 Environmental Geology4、地球物质的化学组成Rock and Minerals in earth Minerals Defined11. A mineral is naturally occurring, inorganic, solid element or compound with a definite chemical compositio
33、n and a regular internal crystal structure. Naturally occurring, as distinguished from synthetic, means that minerals do not include the thousands of chemical substances invented by humans. Inorganic means not produced solely by living organisms or by biological processes. That minerals must be soli
34、d means that the ice of a glacier is a mineral, but liquid water is not. Chemically, minerals may consist either of one element-like diamonds, which are pure carbon-or they may be compounds of two or more elements. Some mineral compositions are very complex, consisting of ten elements or more. Miner
35、als have a definite chemical composition or a compositional range within which they fall. The presence of certain elements in certain proportions is one of 环境地质学环境地质学环境地质学环境地质学 Environmental Geology4、地球物质的化学组成Rock and Minerals in earth Identifying Characteristics of Minerals12. The two fundamental c
36、haracteristics of a mineral that together distinguish it from all other minerals are its chemical composition and its crystal structure. No two minerals are identical in both respects, though they may be the same in one. For example, diamond and graphite (the “lead” in a lead pencil) are chemical th
37、e same-both are made up pure carbon. Their physical properties, however, are vastly different because of the differences in their internal crystalline structures. In a diamond, each carbon atom is firmly bonded to every adjacent carbon atom in every direction. In graphite石墨石墨, the carbon atoms are bonded strongly in two dimensions into sheets, but the sheets are only weakly held together in the third 环境地质学环境地质学环境地质学环境地质学 Environmental Geology
