Drift Gravels Research Articles

교과서에서 사용하는 퇴적물의 입도에 대한 한국어 용어의 검토

The Korean terms of sediment grain size demonstrated in the 30 textbooks of elementary, middle, and high schools and university levels are compared and reviewed, and the problems of its use and alternative terms are proposed. The Korean terms of sediment grain size shown in the most textbooks are the translated terms of the Udden-Wentworth grade scale, and the different terms have been used in these textbooks. In the case of gravels, granule, cobble, and boulder have commonly been translated as wangmorae (king sand), janjagal (fine gravel), wangjagal (king gravel), and pyoryeog (drift gravel) or georyeog (large gravel), respectively. However, it is regarded to be reasonable that they are termed as janjagal, jungjagal (medium gravel), keunjagal (large gravel), and wangjagal, respectively. Adjectives such as 'maeu goun' (very fine), 'goun' (fine), 'junggan' (medium), 'gulgeun' (coarse), and 'maeu gulgeun' (very coarse), attached with each sediment name seem to be suitable to terms for sediments smaller than gravels. Silt has been commonly termed as misa (fine sand) in many textbooks, but it may be appropriate that silt is expressed as silt. Finally, mud, which is a mixture of silt and clay, should be named ito (mud) as shown in several textbooks including Dictionary of Korean Earth Science, though mud has been frequently termed as jinheug (slush or watery soil) in the most of textbooks for elementary and middle school students, and some high school and university textbooks.

Tertiary-age diamondiferous fluid deposits of the lower Orange River valley, Southwest Africa

The Orange River, the principal conduit for transportation of diamonds from the southern African interior to the Atlantic coast, has within its lower valley two recognized suites of gravel terraces in which part of the passing diamond population has been trapped. Both suites lie on eroded bedrock and both are downstream thickening-and-fining coarse clastic wedges. The older and higher terrace suite, comprising the Arries Drift Gravel Formation, is early mid-Miocene in age (19-17 Ma) and is referred to locally as the Proto-Orange terrace. The lower and younger terrace suite, locally known as the Meso-Orange terrace, has not yet been dated but is considered to be Plio-Pleistocene in age. Middle to Late Proterozoic bedrock, underlying both suites of terrace deposits, was deeply eroded during the incision of the Orange River which began in Late Cretaceous times. The Proto-Orange terraces, richer in diamonds than the younger Mesozoic deposits, form low-grade but large-average, diamond-size, gem quality placers which are mainly discussed here. Diamonds are best concentrated in cobble-boulder basal gravels on or close to the rough bedrock contact in three main trapsite settings: scour pools hosting oversize (obstacle) clasts return grades of 10 to 40 carats per hundred ton (cpht); push bars, where the grades range from 10 to 55 cpht; and bedrock highs with their associated oversize clasts, yielding grades of 6 to 12 cpht, do not concentrate diamonds to the same extent as the two former trapsites, but occur over a wider area and thus potentially enrich a greater volume of gravel. The average diamond (stone) size in these three trapsites is also upgraded, ranging from 1.5 to 2.8 carats per stone (ct/stn). The key factors in concentrating diamonds at the bedrock-gravel interface are turbulence scale and intensity created by the rough boundary conditions and the presence of fixed bedrock sites of turbulence, which are stable enough to initiate and retain around them the slow and stable growth of gravel that hosts the concentrated diamonds. The upper, more mobile gravels have far lower concentrations of diamond than the basal gravels, with grades dropping to an average of 0.3 cpht and stone size decreasing to 1 to 1.3 ct/stn. Sites of higher concentration in the upper gravels of the Proto-terraces are bar platforms/riffles (1 to 3 cpht and average stone sizes of 1.1 to 1.3 ct/stn) and bar heads (0.7 to 1.5 cpht and average stone sizes of 1 to 1.3 ct/stn) while bar tails are practically barren. Although the vertical decline in diamond concentration may be attributed to a decrease in diamond supply during the aggradation of the Proto-Orange gravels, the younger, lower grade Mesozoic gravels also display a similar vertical profile. Hence, diamond concentration in the lower Orange River deposits is influenced positively by the occurrence and nature of the localized fixed bedrock trapsites. From an exploration point of view, these fixed trapsites are more difficult to locate, often requiring extensive drilling, whereas the areally extensive but low-grade upper gravels are relatively easy to delineate. During exploitation, the localized but higher grade fixed trapsites provide a reliable source of above average-sized diamonds in an otherwise low-grade.

Manganese cemented Quaternary gravels: birnessite, lithiophorite and quenselite from an example in Wigtownshire

There are at least eleven recorded examples of manganese oxides cementing drift gravels in Scotland (Table 1). However, the mineralogy of these deposits has been largely neglected, the only study being that of Jones and Milne (1956) in Aberdeenshire. These authors discovered the mineral birnessite [(Ca, Na)Mn7O14·3H2O)], which is now known to be a common manganese mineral in modern soil horizons (McKenzie 1980). Literature accounts (Table 1) indicated that the most extensive exposures of managanese cements occurred at the Poltalloch and Luce Bay localities. The former site is no longer exposed, but samples were collected from Luce Bay. In addition, specimens from the two Loch Fyne sites were available in the Hunterian Museum collection and these were also examined to further delineate the mineralogy of the manganese cements. X-ray diffraction techniques (described below) demonstrated that the Loch Fyne cements are composed only of amorphous “wad”. Emphasis was therefore placed on the more extensive cements at Luce Bay. Morphology. The black manganese cement and staining at Luce Bay occur in an 8 m (25 ft) raised beach deposit which extends from Auchenmaig \[NX 233 518] to the Craignarget Burn [NX 261 511\] (Geikie 1878). The beach is composed of well rounded, pebble-sized clasts which show imbrication in places. The manganese oxides (recorded by Paterson–Nesbet 1959 and Yates 1966) are exposed in the section of the raised beach cut by the Craignarget Burn [NX 261 511]. They appear as distinct dark patches, up to 2 m above the stream bed, covering . . .

Roads and National Welfare

IN NATURE of December 19, 1901 (p. 149) is given a criticism of a work, in which some essential points in the making and maintenance of roads are strongly insisted on. At p. 156 of the same number there appears an excellent commentary on Mr. Balfour's speech to the students of the Goldsmiths' Institute at New Cross on December 12. With your comments I am in thorough sympathy, and would beg leave to point out that the two subjects are far more closely connected than might at first appear. Excellence and superiority in manufactures and commerce depends on very many elements, as you know, one of the most important of which is the “item” “carriage or transport.” British superiority in many manufactures and markets has depended, and will henceforth largely depend, on that one item principally (take the case of iron ores), and to maintain superiority it must receive in the immediate future more careful attention and scientific treatment. Roads in their different forms enter largely as factors into the general question of “transport,” and if trade superiority is to be maintained they must be looked after and treated, all over these countries, in a more scientific and skilled manner than that now prevalent in the United Kingdom. For that end there must be attained, as soon as possible, uniformity of make, treatment and control, and the highest efficiency as regards care and maintenance, and to ensure these results they should be placed under the charge of a body of trained engineers, such as those of the “ponts et chaussées” of France. The question to a certain extent resembles that of the currency of the realm, and as there is a perfectly uniform coinage for every part of it, so should the make and use of the roads be of one standard all over the kingdom, in the best interests of all who travel or convey goods. The Board of Trade controls the railways, why not a Board or Department for the roads? and thus obviate the many absurd and scandalous practices which exist and are allowed to prevail, to the great discomfort and loss of the community. Allow me to give my experience of what is taking place in the township of Pembroke (Dublin). The road “metal” mostly in use is simply the coarser riddlings from the drift gravel so abundantly and cheaply worked in the neighbourhood of the Town Hall. The stones, perfectly rounded, incapable of taking bond and largely composed of entirely rotten elements, are loosely thrown here and there, where prominent holes appear. Mr. Beete Jukes, the former head of the Geological Survey of Ireland, remarked when he saw the material used, that boiled potatoes might as well be employed, and the rapid wear fully bears out the correctness of this judgment, and hence a large staff of scavengers and carts, discomfort for all classes of road-users, and steady increase of rates. In a southern county I have seen the road surface worn into the form of the section of an inverted arch, and was informed by a competent authority that the county surveyor, a Whitworth scholar, secured the place as the result of a Civil Service examination, the pay being about 800l. per annum, and thus secured, proceeded to develop a private practice as civil engineer, leaving the roads to attend to themselves. Many other examples of this nature might be given. As to the importance of good roads from a military point of view, it should be unnecessary for me to refer to it. I see from time to time the Dublin garrison companies and battalions out on marching exercise and notice the draggled appearance in which the men come home when the weather is in any way moist or rainy, and reasonably associate this condition with the bad state of the roads about Dublin. The Romans certainly knew better on this branch of military engineering, and might still be copied. As for agriculture, the Americans have gone thoroughly and systematically into the question, and are taking effective measures to put their road systems into a proper working state, and to have them kept up to it. I trust, Sir, that you will excuse these rather extended observations and that you will see your way to urging the pressing importance of a uniform and general system of road making and maintenance for the kingdom on the grounds of high State utility, commercial importance and agricultural necessity.

Note on Drift-gravels at West Wickham (Kent)

There are two deposits of Drift–gravel at West Wickham upon which I propose to offer a few remarks. The first occupies the bottom of a valley which winds round the southern and western sides of Hayes Common and thence to Bromley. This is shown on the Geological Survey map, but there it appears that the Drift–gravel terminates somewhat abruptly near Keston. The valley itself, however, runs much farther south, extending to the North Downs near Tatsfield and roughly coinciding with the direction of the boundary–line between Kent and Surrey, but following a course varying from 2 miles to ½ mile east of that boundary. A fairly good section of the gravel in the bottom of this valley may be found in a pit at Gates Green, a point near the junction of the three parishes of West Wickham, Hayes, and Keston. The beds exposed consist of rolled flints, fragments of Chalk, and bands of sand containing minute fragments of flint and portions of Chalk–fossils, including a large proportion of foraminifera. The beds also contain a few rolled fragments of ferruginous sandstone, probably derived from the Lower Greensand. The character of these beds is precisely what might be expected from the destruction of Chalkbeds. The fragments from the Lower Greensand also go to show that these gravels have a definite, although perhaps not direct, relation to the forces which excavated and denuded the Wealden area. The bands of sand indicate, I would submit, periods of comparative tranquillity

The Glacial Drift in Ireland

SINCE the publication of Prof. G. A. J. Cole's letter in NATURE (vol. xlvii. p. 464), in which he records the discovery of pebbles of the Ailsa Craig Riebeckite-eurite from the drift gravels on Killiney strand, numerous observers have noted its occurrence in several places along the east coast of Ireland, but hitherto, I believe, not further south than Greystones, Co. Wicklow. Owing to the special interest of this rock, both to glacial observers and petrographers, it may be worth mentioning that two weeks ago I found one small pebble (about 3 c.m. square) of the rock on the shore of Tramore Bay, Co. Water-ford, nearly 80 miles further south than the previously mentioned locality, and 230 miles from Ailsa Craig.

On Palaeolithic Implements from the Drift Gravels of the Singrauli Basin, South Mirzapore

On Palaeolithic Implements from the Drift Gravels of the Singrauli Basin, South Mirzapore

Primæval Man and Working-Men Students

UNDER the above heading you published a letter from me in NATURE, August 2, 1883, p. 320, giving the names of four thoughtful artisans, who, after studying the Pitt-Rivers collection of antiquities, and reading my notes in NATURE, had made finds of Palæolithic implements in Essex. Ten months have passed since that letter was published, and a fifth student, Mr. W. Swain, has now joined the original party of four. On Sunday, June 15, these admirable workers called upon me with their recent discoveries. They consisted of fifteen Palæolithic implements found in the drift gravels of Leyton, Wanstead, and Plaistow, with the usual complement of flakes. Some of the implements were of the older abraded class, others were as keen as knives, and from my “Palæolithic Floor,” traces of which, as I have pointed out, may be seen in Essex. Three nondescript tools were also lighted on, and four hammer-stones of quartzite with abraded ends, one from Nazing; five Neolithic instruments from Jordan's Wood, and a large collection of flakes.

Herbaceous Stem on a Palæolithic Implement

INSTANCES are so extremely rare where vegetable material (as old as the drift gravels) is found adherent to drift implements, that the following instance is probably worthy of note:— Amongst my collection of Palaeolithic implements from the neighbourhood of Bedford, I have one perfectly unabraded example—bright ochreous yellow in colour from its long deposition in the drift. Near the middle of the implement there are the remains of some herbaceous stem firmly fixed to the flint; the colour of the vegetable material is bright ochreous, and under the microscope the vegetable structure (especially the vessels) is most clearly seen; the patch is an inch long and about a quarter of an inch in average width; it has not the stellate cells of the rush. The material has been protected in a depression in one of the artificial facets of the implement, and in a second position somewhat nearer the butt, there is further trace of the same material. My opinion is that these grass stems (or whatever stems they may be) were possibly wrapped round the basal end of the implement as a protection for the hand against the asperities of the flint. The asperities are very noticeable in the instrument referred to, as it has a sharp cutting edge at the butt, with none of the original bark of the flint left for convenience of holding. The vegetable material is undoubtedly as old as the implement, and the unabraded condition of the stone may account for its position in the facets.

The Disputed Beads from the Drift

It is not improbable that, in the eager search for flint implements, some of us may underrate the importance of objects which might serve to throw light upon the interesting subject of the antiquity of the human race. Anxiety not to lose any evidence bearing upon this point will, doubtless, be accepted as a sufficient excuse for re-opening the question as to the perforated balls found in the Drift, displaying proofs of the workmanship of man. We have had conflicting opinions upon these objects, but I am not aware that anything decisive has been published. It is desirable, under such circumstances, to obtain as many facts as possible, and get the question settled. My first acquaintance with these objects occurred about fifteen years ago; for as I was uncovering some Anglo-Saxon remains in the Kempston Gravel-pit, near Bedford, I found several round stones perforated through ; and so strongly was I impressed at the time that they were the personal ornaments of the ancient chieftain just exhumed, that I actually presented them to the Archaeological Society as Saxon beads. Subsequent examinations of the Drift gravels, however, convinced me that the balls were of an earlier period than the Anglo-Saxon, whether works of art or natural productions. They are described by some naturalists to be specimens of the Chalk fossil named as the Coscinopora globularis; but the great question for consideration is, how did they become perforated? The theory put forth by some objectors is that they were bored by an insect or worm when they were in their soft, primitive condition; but it is difficult to understand how the most voracious insect could seize upon a perfectly round object and drill through it, most accurately, a thoroughly straight tunnel of uniform bore.