Key+events

Law of superposition Principle of original horizontality Principle of lateral continuity Principle of lateral continuity || This is the corner-stone of chronology and of modern understanding of the rock cycle. Steno's observations led directly to the establishment of processes and ultimately to the uniformitarian assumption. By laying out the basic rulers of sedimentary processes, he set out a framework for understanding and codifying these processes, still at the heart of modern geological, and archaeological, research. || Uniformity of process Uniformity of rate Uniformity of state ||
 * Date || Event || Key people || Key texts || Context || Significance ||
 * 1660-1664 || Work concerning the age of the earth using biblical texts. || Archbishop Usher || //Annales veteris testamenti, a prima mundi origine deducti//, 1660. Follow up work: //Annalium pars postierior// 1654, in which he calculated the precise date and time of the creation. || Usher claimed that there were 4004 years from creation to Christ, based on a mathematical understanding of biblical ages. || Usher's proclamation was an early attempt to investigate the antiquity of the earth and human kind's place in this. Using the tools at his disposal, he attempted to discuss the origins of life on earth and how empirical evidence could allow researchers to ascertain the age of the earth, within his own framework. This paved the way for researchers to begin to experiment, using the tools at their disposal, and to discuss issues such as chronology in an evidence-based context. ||
 * 1669 || Discovery of the nature of sedimentation || Nicolaus Steno || //Dissertationis prodromus// 1669. || Used inductive reasoning based on empirical observation to forward the principles of stratigraphy:
 * 1778 || Publication of //Les epoques de la nature// and extensive experimentation || Georges-Louis Leclerc, Comte de Buffon || //Les epoques de la nature// 1778 || Buffon experimented by making a small iron model of the earth and, based on the cooling rate, forwarded an age of 75000 years as the age of the earth. || This move towards empirical deduction based on experimentation paves the way for the application of a hypothetico-deductive approach to the subject. Although not deductive reasoning in its purest form, the application of his understanding of thermodynamics and geological process moved towards a hypothetico-deductive approach. ||
 * 1785 || James Hutton's principle of uniformitarianism || James Hutton || //Theory of the Earth; or an Investigation of the Laws observable in the Composition, Dissolution, and Restoration of Land upon the Globe// read to the Royal Society of Edinburgh, April and July, 1785. //Concerning the System of the Earth, its Duration and Stability.// Abstract read to the Society, July 1785. || Hutton's work (later emphasisied by Lyell) establishing the principle of uniformitarianism. || This principle underlies all theory of chronology, geological process, geography, archaeology and quaternary science, stating that as things happen now, so this can be applied to the past. Initially this is applied to geological processes and processes such as sedimentation. the significance here is for chronology and time-depth, and the inference that the processes took place over the same time frames as are observed empirically in modern systems. ||
 * 1788 || Forwarding the principle of a rock cycle || James Hutton || Papers presented to the Royal Society of Edinburgh, 1788 || Hutton's work, later developed by John Tuzo Wilson || Hutton first proposed a rock cycle following research in Scotland, where he looked for evidence of uniformitarianism and the principles underlying his presentations to the Royal Society. His rock cycle was seen as having 'no vestige of a beginning, no prospect of an end'. The discovery of plate tectonics led to a revised cycle, primarily by John Tuzo Wilson. ||
 * 1794 || Publication incorporating all Hutton's research and opposing alternative theories. || James Hutton || //An Investigation of the Principles of Knowledge and of the Progress of Reason, from Sense to Science and Philosophy,// 1794 || A synthesis of the research described above, with alternative theories by Buffon, and Burnet. || An important synthesis of Hutton's research. ||
 * 1796-1811 || Publication of a monograph || Georges Cuvier || 1796 paper on fossil elephants presented to the National Institute of Sciences and Arts in Paris. 1811 Monograph, with Brongniart, on the stratigraphy of the Paris basin (final version, work begun in 1808). || A proponent of catastrophism, Cuvier also published on biology and classification of animals. His 1796 paper, on fossil elephants, made his position, as a proponent of catastrophism, clear. The publication in collaboration with Alexandre Brongniart, followed on from his earlier work (a paper in 1794) in which he first laid out his ideas. || Still discussed as a viable alternative to uniformitarianism, especially among faith groups, the theory of catastrophism still has relevance in the curriculum. Cuvier, is a prominent exponent of this theory. ||
 * 1815 || William ‘strata’ Smith’s geological map of Britain || William Smith || Geological map of Britain || A geological map, describing the geology of Britain, and in which Smith discussed fossil life forms as isochronous markers in sedimentary systems, and establishment of a temporal link between layers. || This was the link between fauna and strata, leading to modern principles of biostratigraphy ||
 * 1833 || Further development of Uniformitarianprinciples || Charles Lyell || //Principles of Geology//, 1830-1833 (three volumes) || Refining the principles of uniformitarianism || the establishment of four rules in uniformitarianism: Uniformity of Law
 * ~1847 || Discovery of human artifacts with extinct faunal forms || Jaques Boucher de Perthes || //Antiquites Celtiques Et Antediluviennes,// begun 1847 || Discussed the discovery of human artifacts with extinct faunal forms before the establishment of the antiquity of humankind and our place in geological time. || Although most significant for archaeology and specifically the study of humankind and its place in deep time, this discovery contributed to the principles biostratigraphy, later established and codified by William Smith and others. This allowed researchers to consider the relationship between artifacts and forms found in the same sedimentary contexts and how sedimentary layers could link forms together. ||
 * 1946-1955 || Development of radiocarbon dating || W. F. Libby, J. R. Arnold || Libby, W. F. 1946. Atmospheric Helium Three and Radiocarbon from Cosmic Radiation. //Physical Review// 69 (11-12): 671–672. First published description of concept, coined term "radiocarbon". Arnold, J. R. and Libby, W. F. 1951. Radiocarbon Dates. //Science// 113 (2927): 111. Libby, W. F., 1955. //Radiocarbon dating//, (2nd ed.), University of Chicago Press. || 1946. Allowed the principles of radiometric dating to be applied to stratigraphic contexts. 1947-1948 First 14C date: wood from tomb of Zoser (Djoser), 3rd Dynasty Egyptian king (July 12, 1948). Historic age: 4650±75 BP, Radiocarbon age: (C-1) 3979±350 BP [average of 3 determinations 3699±770, 4234±600, 3991±500.] 1949. First curve of knowns published. 6 data points (using seven samples) spanning AD 600 to 2700 BC. Half life used: 5720± 47 years. In this, artifacts of known calendar age were dated with radiocarbon, and a curve produced to calibrate the radiocarbon age, so that it equated to calendar time. || This technique can only be applied to organics, and, owing to its half-life, cannot be used beyond 40000 years. It must also be calibrated, which cannot be done with certainty beyond 26000 years. However, this allowed the application of absolute dating to the contents of different strata strengthening the link between strata and chronology and allowing it to be quantified. Later research showed that radiocarbon dating could be used for practical applications in archaeology and geography, although the need for calibration was not established until the publication of the first 'curve of knowns'. This was the first attempt at radiocarbon calibration, allowing radiocarbon time to be linked to calendar time, and comparative chronology. ||