Older Period Research Articles

The strangest 0.05% of the geological history

The historical geological perspective is the main cause that much more is known about young rocks than about older ones. Most is therefore, obviously, known about Quaternary rocks, but this does not imply that the Quaternary is understood much better than the older periods. On the contrary, facies distributions — particularly in glacigenic successions — seem often so much more chaotic than in successions from other periods that the Quaternary could be considered as the strangest 0.05% in the geological history. It is most unlikely, however, that the Quaternary differs so much from other periods. It must therefore be concluded that many of the apparent discrepancies between Quaternary and older rocks either are due to different approaches followed during investigations, or reflect a geologically still immature situation, because destructive agents have had insufficient time to remove material or to obscure specific characteristics. In spite of these probably fundamental differences between Quaternary and older sediments — that will disappear with time — it is likely that the application of Quaternary investigation methods to older rocks — and that of hard-rock research methods to Quaternary successions — may contribute substantially to a better understanding of both the remote geological past and the nearby geological history.

Source and timing of gold and other mineralization in the Red Lake area, northwestern Ontario, based on lead-isotope investigations

The problems of the timing and source of gold mineralization and the sulfidation mechanism in the Red Lake area, north-western Ontario, have been addressed using more than 300 Pb-isotope analyses of more than 250 samples of sulfides, oxides, gold, and potential source rocks. Base metals and some gold from the Campbell and Dickenson mines are interpreted to have been mainly derived from the mafic–intermediate and felsic volcanic rocks of the lower sequence at ca. 2865 Ma, the model age calculated for samples of gold, chalcopyrite, pyrite, and galena. Other samples of gold are considered to have formed at younger ages, perhaps at ca. 2700 Ma. Differences in isotopic patterns for deposits in possibly different deformation zones but hosted by rocks of the same age and composition, e.g., Campbell–Dickenson, McFinley, Cochenour Willans, are interpreted to mean that some of the deposits formed at different times or from different sources or both (i.e., by multistage processes). The older period of gold mineralization is supported by a 2865 ± 10 Ma Pb–Pb isochron age (mean square of weighted deviates (MSWD) 2.9) for Cu–Ni and Fe sulfides and a similar model age for pyrite from the Bridget Lake prospect in the western sector. Younger mineralization at ca. 2700 Ma is represented by, for example, disseminated sulfides in the Dome stock, Balmer Lake arsenopyrite, the Red Summit mine in the Red Crest stock, sulfides and gold from the McFinley mine, and the model age for the Abino galena. A well-constrained Pb–Pb line for magnetites, mainly from 2700–2730 Ma felsic intrusions, gives an apparent age of 2660 ± 10 Ma (MSWD 3.7). This event may represent late-stage hydrothermal activity. Analyses of gold grains yield very complex isotopic patterns possibly because of remobilization and the very low contents of Pb in the gold grains. In environments such as Red Lake, Pb-isotope analyses of gold appear to give unreliable estimates of genesis and timing.

Responsibilities in Syntax

ABSTRACTSyntax has received major attention in recent linguistic study, with many efforts at formalization. Publications have taken datalargelyfrom earlier treatments characterized as traditional. In spite of claims for theoretical advances, no treatments of syntax have been produced to replace the earlier, supposedly outmoded treatments. Rather, theoretical claims, such as those advanced on the advantages of a generative approach and formah'sm, have been dismissed by leading figures in the field. More recent grammars, like Mitchell's for Old English and Engel's for modern German, generally observe the traditional approach. Among problems, those for older periods lack the historical approach, as of expression for reflexivization. Investigations into these and other syntactic categories are needed. Further, outstanding works of the past, such as those by Delbruck, should be made available. In addition, specific handbooks, as on Old High German syntax, should be undertaken; in preparation, some texts of the time require reediting.

Beitra¨ge zur allgemeinen geomorphologie der tropen und subtropen Geomorphodynamik und vegetation klimazyklische sedimentation panplain/pediplain-pediment-terrassen-treppen

Beitra¨ge zur allgemeinen geomorphologie der tropen und subtropen Geomorphodynamik und vegetation klimazyklische sedimentation panplain/pediplain-pediment-terrassen-treppen

On the origin of recent vertical movements of the east Asiatic continent island systems

Recent slow vertical movements in Sakhalin, Japan and Kamchatka are mainly the continuation of modern movements that began in the Quaternary and older periods. In many cases positive and negative Recent vertical movements coincide spatially with uplifts and troughs, respectively. In some cases Recent movements are not stable in their sign, but are influenced by short-period “pulsations”; their total meanings for long periods of time according to their sign correlate on the whole with modern structure forms, being expressed as a relief. Spatial distribution and configuration and also conjunction of the uplift and trough areas, accompanied by variations of gravity anomalies, are strongly similar with the character of rapid vertical movements, connected with Recent volcanic activity and earthquakes. This circumstance allows us to assume their common origin also, connected with supply of sialic material into the Earth's crust. Cross-sectional sizes of uplifts and wave lengths of vertical movements allow us to determine the depth of foci (zones), where concentrations of supplied sialic material occur. For the most part of structures with sizes up to 60–70 km these foci are distributed at the depths of 10–15 km. There are also structures with longer wave length, which are connected with the formation of zones of partial melting near the Moho discontinuity or in the upper mantle. The occurrence of such foci is confirmed in many cases by the presence of zones of increased electric conductivity and decrease of the elastic wave velocities in the Earth's crust and upper mantle. The vertical movements mentioned above, which are apparently associated with a step-like rise of magmas of different composition, formation and evolution of partial melting zones on different levels, are supposed to be a widely spread phenomenon.

Criteria and problems in estimating global lateritic nickel resources

Although two-thirds of the present nickel production is derived from nickel sulfides, lateritic nickel reserves are estimated to be around three times as large as those of sulfides. This discrepancy is largely caused by the mineralogical complexity of lateritic nickel which precludes low-cost beneficiation by conventional physical methods. Nevertheless, lateritic nickel reserves are bound to become increasingly important because of expected metallurgical advances. Lateritic nickel deposits were formed from peridotitic rocks on peneplaned surfaces during a tropical or subtropical climate. The most important deposits were formed during the Tertiary and the lateritization process still continues in deposits situated in the present tropical or subtropical belts. Other deposits, like those in East Europe and Greece, were formed during much older periods (Palaeogene-Cretaceous). The various types of lateritic nickel deposits, covered or uncovered,in situ or transported, are listed and their characteristics briefly mentioned. Large differences exist in depth, grade, specific gravity, and mineralogical composition—the latter especially in the nickel silicate section as opposed to the overlying limonitic section. These large differences exist even within one individual mining area. Because of the mineralogical complexities and highly irregular boundaries of lateritic nickel deposits (especially the upper and lower boundaries of the nickel silicate section), thorough studies are required to determine the mineralogical composition and ratios of the components. Only then may it be possible to specify with confidence the most suitable metallurgical process which has a strong bearing on the cost and consequently the viability of the deposit. This condition makes the exploitability rating in the McKelvey classification diagram relatively more difficult. Because of the quickly changing geological attributes of deposits even within limited areas, it seems necessary to develop various deposit models for many, if not most, individual metallogenic regions. It does not seens justified or practical to use estimation methodologies based on straight extrapolation. This is especially the case when dealing with the young uncovered type of deposit which constitutes the bulk of global resources. Consequently methodologies no. I (areal value estimation. Cargill, Meyer, Picklyk, Urquidi, 1977) and no. 2 (volumetric estimation) are not considered suitable. It is thought that methodology no. 3 (abundance estimation) in conjunction with no. 5 (Delphi estimation) would work satisfactorily but, as could be expected, the most meaningful results should come from a combination of methodologies nos. 4 (deposit modeling), 5 (Delphi estimation), and 6 (integrated synthesis). A classification of leteritic nickel deposit types is proposed.

Late Quaternary paleosols in the western and central Cordillera of Colombia

More or less well preserved paleosols were studied in the submontane and montane zone of the Western and Central Cordillera, Departamento del Valle, Colombia. Their Pleniglacial age was ascertained by radiocarbon analysis of charcoal which was, in several sections, found associated with the basis of volcanic ash deposits. The two ash periods which provided the bulk of the volcanic parent material seem to have occurred about 30 000 and 10 000 yr. B.P. The paleosols developed before and immediately after the older period (Middle Pleniglacial). The characteristic morphological traits — a uniform grey horizon of low humus content and with a basal iron pan — indicates a cold humid environment of low evapotranspiration and low organic turnover. Such soils do not form today but were characteristic for the Middle Pleniglacial soil cover from altitudes of 1500 to 3500 m. Increasing stable humus content in paleosols after 30 000 yr. B.P. apparently indicate a turn towards drier conditions, i.e. a growing influence of Gramineae after a predominance of wooded vegetation, quite in agreement with the pollen-based paleoclimatic concept of Van der Hammen. This paper demonstrates the distribution of truncated and transported paleosols relicts as a result of the great degradational phase which reshaped the soil mantle probably between 20 000 and 10 000 yr. B.P. The type of paleopedological soil formation process is discussed in some detail.

The Early Stage of the Burmese-Malayan Geosyncline

The history of thi s geosyncline is divided into three stages: (1) Devonian and older ; (2) late Devonian to middle Triassic; and (3) la ter Mesozoic period. The so­ called Pre-Cambrian metamorphic rocks require a further confirmation of their ages Upper Cambrian is the oldest dated sediment of th e geosyncline. Three facies named Shihtien, Naungkangyi, and Thungson, can be distinguished in the Ordovician formation. In the later Palaeozoic sequence carbonate-rich and carbonate-poor facies altern ate twice or more with intercalations of graptolites and tentaculites facies and other clastic facies . Broadly speaking, the early stage was the age of epirogenic undulations, whil e the second stage was the age of embryonic foldings by which the geosyncline was partly modified, and at length it was wholly deformed and consolidated by Mesozoic orogenies. In the Thai-Malayan Peninsula a Carboniferous fauna was first described from Phattalung by Reed (1920), but for a long time little was known of the older history (Alexander, 1956). In the last 15 years, however, all of the Palaeozoic Systems were documented by fossil evidence in the southern area of this zone. Therefore, the "Sino-Burmese-Thailand-Malayan geosyncline" was abbreviated to the "Burmese­ Malayan geosyncline" (Kobayashi, 1964). In my opinion it is relevant to divide the history of its development into three stages. Main events in the early stage were wide and gentle movements of the geo­ syncline, causing oscillations of shore line in the Devonian and older periods as revealed in the gradual variations of sedimentation and local discordances. In the middle stage, from late Devonian to middle Triassic, local crustal disturbances and igneous activities took place, but they were not strong enough to change the principal outline of the geosyncline. During the Mesozoic Era, however, the geosyncline suffered strong orogenic activity accompanied by the emplacement of granites through which the whole geosyncline has become emergent and consolidated. CAMBRIAN SEDIMENTS AND THE SO-CALLED PRECAMBRIAN ROCKS Upper Cambrian trilobites occur in shales at Paoshan and Mangshih, west Yunnan, in the north, and in the Tarutao sandstone at Tarutao island just to the north of the Thailand-Malaysian boundary (Sun, 1939, Kobayashi, 1957, Lu, 1964). In the Langkawi Islands to the south of the boundary the thick "Machinchang

Geology of Thailand and her Surroundings

This is a critical review of the geology of the region. The stratigraphy is discussed in dividing the terrain into three tectonic units as shown in fig. 1, and schematized as indicated in the table on page 6. The best Palaeozoic sequence can be seen in the west zone. There however, the Devonian system is unknown, but present in the east flank of the Pak Lay anticline in the median zone.The Khorat series in the Khorat plateau in the east which contains dicotyledonous plants must be Cretaceous, instead of Jurasso-Triassic. It is quite probable for it to extend easterly into the Indosinias supérieures of South Laos which yielded Senonian Reptiles and non-marine Trigonicides faunule and southerly into Grès continentales of Cambodia which is also Upper Cretaceous, if not Palaeogene. Thus it is certain at the least that marine Jurassic and Triassic formations should be eliminated out of the continental Khorat series.The Triassic formation in the median zone is accompanied by eruptive rocks, like the Pahang volcanic series, but it is known paralic in North Laos. In the west zone there are Triassic and Jurassic formations devoid of volcanics. They are strongly folded, while the Cretaceous (?) red sandstone of Tenasserim is gently monoclinal.It is probable that the old Cimmerian folding in the median zone has confined the flooding of the Jurassic sea to the west zone and that crustal movements have taken place in the still older periods on the west side of the Indosinian massif. Nevertheless it is quite warranted that the folded mountains through the middle-west of Thailand has not been established by the Cretaceous period. Older rocks are intruded by granitic rocks, but not the Khorat series as well as the Tenasserim sandstone. They are both continental, and slightly undulated or simply inclined with low angles. Thus the vast terrain turned out land in the Palaeogene. The influence of the Himalayan orogeny was weak in this part of Asia.

Carboniferous Stratigraphy and Structural Geology of New Brunswick, Canada

The Carboniferous stratigraphy of New Brunswick is described in some detail and the structure is discussed and illustrated by geological maps and cross sections. An attempt is made to record many of the data accumulated by geological surface mapping and by seismic, gravimeter, and magnetometer surveys, and to interpret them in the light of recent wildcat drilling and other subsurface geological information. Particular emphasis is placed on the use of seismic surveying in rationalizing the complex structure of the area and in interpreting the attitude of faults in depth. It is felt that sufficient information is now at hand to provide a clearer geological picture of the area. A new subdivision of the Pennsylvanian strata of New Brunswick is presented. The time break between the Mississippian and Pennsylvanian is pre-Enrage, coinciding with a major period of deformation. A still older period of deformation is now recognized within the Moncton group; this marks the close of Horton time. Due to lack of subsurface control in the greater part of the Moncton basin and the absence of lithological or paleontological horizon markers generally, it is usually impossible to subdivide the Upper Red Bed series which is mapped as the Moncton group. Accordingly, although the Hillsborough formation is still shown as belonging to the Moncton group, it is definitely recognized as being post-Horton in age and as such is more closely related to the Windsor in time. Abundant evidences of oil exist and large structures in which oil could accumulate are known to occur; however, wildcat drilling to date has failed to find suitable permeability.

DEVELOPMENT OF SELF AND HYBRID DATURA EMBRYOS IN ARTIFICIAL CULTURE

DATURA INVESTIGATIONS in recent years have included growth of numerous interspecific hybrid embryos in artificial culture. Results obtained with embryos from different species combinations indicated that such embryos were unlike in their response to the nutrient solutions used. The following experiments were une MIcLean, 1946). Seitz-filtered malt extract added to the culture medium was found to promote embryo growth and was substituted for cocoanut milk. MATERIALS AND METHODS.-Seed development of the embryos used in the present investigations has been previously described (Sanders, 1948). They are self embryos of Datura discolor, D. inoxia, D. metel and D. stramonium; hybrid embryos from the compatible cross D. stramonium X D. discolor; and hybrid embryos from five incompatible crosses in which relatively numerous arrested embryos are formed. The incompatible crosses are D. discolor X D. stramonium, D. inoxia X D. discolor, D. inoxia X D. metel, D. inoxia X D. stramonium, and D. metel X D. inoxia. Self embryos of these species grow well in culture when dissected at stages of development ranging from the late heart stage to the mature embryo. Proembryos 0.1 mm. in diameter occasionally grow in culture but as a rule they do not. Embryos for these experiments were, therefore, taken at approximately the early heart stage when there is a real possibility that the embryo will grow and also that it will be more susceptible to changes in the nutrient than at older periods of developmient. At 1 Received for publication June 16, 1949. Contributions from the Department of Botany, Smitlh College, New Series No. 36. The article is taken from a thesis written under the direction of Dr. A. F. Blakeslee and submitted to the faculty of Smith College in partial fulfillment of the requirements for the degree of Doctor of Philosophy. this stage the top of the proembryo has flattened out, cotyledon primordia are just beginning to appear, and the longitudinal axis is about 0.2 mm. Slightly larger embryos were occasionally used because of the difficulty in obtaining the exact stage desired. Degree of embryo development at the time of dissection must be considered since it has been found that growth of embryos in culture varies with the stage of the embryos. Hybrid embryos from the compatible cross (D. stramonium X D. discolor) were also dissected at approximately the early heart stage though in some cases cotyledon differentiation was not evident. Embryos in this cross do not always differentiate normally so that such cases were probably examples either of the lack of normal differentiation or of the delay of differentiation. Hybrid embryos from incompatible crosses, due to the difficulty of obtaining a sufficient number for the experiments, were dissected at the age when the most embryos could be found, old enough for developing embryos to be seen, and young enough for the embryos to be still viable. This age varied with the cross (Sanders, 1948). Embryos were dissected out of the seeds under sterile conditions with the aid of a dissecting microscope and introduced into cotton-plugged vials containing culture media which had been sterilized by autoclaving at 15 lbs. pressure for 20 min. When malt was used in the nutrient, it was sterilized by Seitz-filtering and added to the vials after autoclaving. All nutrients to be compared were used in the same experiment to keep environmental factors affecting growth the same for all. Embryos were introduced into the vials along rows at right angles to the rows representing different nutrients in order to distribute embryos from the same capsule and to balance differences in size and vigor of the embryos among the nutrients. Vials were kept in an incubator at a constant temperature of 26?C. Growth has been expressed as the number of times the embryos increased in size during their days in culture. Size was determined by measuring the longitudinal axis of the embryo or of the largest outgrowth in the cases where multiple growth occurred. Measurements were made the dav of dissection and again after the prescribed number of days in culture. The growth value used is-final average size/original average size. Results are expressed as growth values or as the average of growth values from several experiments. Each experiment was done twice, occasionally three times, with ten embryos per nutrient so that the results are based on at least twenty vials per treatment. Data from individual experiments which were averaged together to obtain the growth values

Jericho

PROF. JOHN GARSTANG'S survey of the results of his excavations at Jericho in his article in the Times of December 6, following on his lecture at the University of Liverpool on November 17, affords a consecutive story of the history of the city which it is possible to accept with assurance in the light of the excavations of last season. Among the more interesting features are the evidence of Babylonian influence in the Early Bronze Age and the conspicuous rarity of Cretan and Mycenaean motives under the eighteenth dynasty when they might be expected. Four separate and distinct defensive systems have been differentiated, of which the earliest, belonging to the Early Bronze Age (c. 2500-2100 B.C.) rested on deposits of a still older period. The period of the city's greatest expansion was in the third phase (Middle Bronze Age II), which is marked by a cultural change. Under the Hyksos at that time, the city walls were much extended; and the character of the Palace and other buildings suggests that Jericho, as the residence of a Hyksos governor, had become a city of more than local importance. This phase comes to an end at about 1600 B.C. when the city was destroyed, presumably by the Pharaohs. It was rebuilt, but restricted within the bounds of the earlier area of occupation. From that time onward its history can be traced by means of scarabs and painted pottery having a range of dates between 1600 and 1400 B.C. At the latter date under Ameno-phis III the normal life of the city ceases abruptly. All the buildings of the Palace area and the few houses against the city wall bear witness to a great catastrophe-the indications are an earthquake- followed by an intense fire while the rooms were in occupation. Thenceforward until about 900 B.C. the site was practically deserted.

Notes on the editions of the Arabic Poets 'Abid ibn al-Abras, 'Amir ibn at Tufail, and 'Amr ibn Qami'a published by Sir Charles J. Lyall

Since the publication of these three important collections of ancient Arabic poetry, I have had access to two valuable old works dealing with the older period of Arabic poetry, viz. the second volume of Ibn Qutaiba's Kitāb al-Ma'ānī (India Office, No. 1155) and the Ḥamāsa of Hibat Allāh Ibn ash-Shaǧarī (Paris: Arabe No. 6018), the latter in photographs belonging to Mr. Storey.

Color in Old English Poetry

It is a somewhat singular fact that although students of our language and literature have been carefully gleaning their chosen fields and leaving scarcely any entirely new theme for investigation, there should remain practically untouched a subject of high interest and æsthetic importance,— I mean the use of color in poetry. To some extent the matter has attracted attention in the study of other literatures than ours. Critics often remark upon the brilliant color-sense of the Celtic poets and of the writers of the Old Norse sagas and poems. Gladstone devoted a long section of his Homeric Studies to the color-epithets in the Iliad and the Odyssey; and a German scholar, with characteristic thoroughness, has made an exhaustive study of the color-words in the entire body of the Latin and Greek classics. But an adequate investigation of the development of the color-sense in English poetry is yet to be written. I know of but one paper that treats the matter in any detail, and that paper is confessedly tentative and leaves the older periods untouched. As for color in Old English poetry, a few words by Professor March and a few more in a very rare paper by Dr. Sweet exhaust about all that has been said on the subject.