A Road Section near Guy's Hill, Jamaica

1942 ◽  
Vol 79 (4) ◽  
pp. 241-252 ◽  
Author(s):  
C. A. Matley ◽  
Frank Raw
Keyword(s):  
Sedimentary Rocks ◽  
Plutonic Rock ◽  
Igneous Rocks ◽  
The Road ◽  
Road Section ◽  
Igneous Intrusions ◽  
Microscope Slides

The rocks exposed along the road between Linstead and Guy's Hill, Jamaica, were described by Dr. C. T. Trechmann in this magazine in 1936 (pp. 259–260). The chief object of his account was to prove that the igneous rocks there were intrusions later than the associated Cretaceous and Tertiary limestones, which, according to him, had been metamorphosed into hornfelses, some of which, he stated later (1937, p. 561), he knew to have an “igneous” appearance under the microscope, “which tends to support my contention that in Jamaica we have sedimentaries altered in situ into rocks that would ordinarily be classified as igneous.” Dissent from his descriptions and interpretations was expressed by C. A. M. (Matley, 1937, pp. 501–3), the criticisms being mainly based on an examination of Trechmann's own microscope slides by F. R. A visit to Jamaica by C. A. M. in 1939 allowed him to study this road and to collect a suite of rocks for petrological examination. The results show that Trechmann's interpretation cannot be sustained. There is no granodiorite or other plutonic rock present, no metamorphism hornfelsing the sedimentary rocks, and no igneous intrusions into the Tertiary limestones.

Two for the price of one: Doris Livesey Reynolds (1899–1985)

2020 ◽  
pp. SP506-2019-162 ◽  
Author(s):  
Cherry L. E. Lewis
Keyword(s):  
Royal Society ◽  
Sedimentary Rocks ◽  
Igneous Rocks ◽  
Chemical Changes ◽  
Geological Society ◽  
Igneous Complex ◽  
Igneous Intrusions

AbstractDoris Reynolds, known less commonly by her married name Doris Holmes, was an English geologist and petrologist. She is best known for her role in the Granite Controversy that started in the late 1930s and continued throughout the 1940s and 1950s, and particularly for her contribution to the concept of ‘granitization’ in the formation of granites. She was greatly influenced by Catherine Raisin, who introduced her to petrology at Bedford College for Women where Reynolds studied for her first degree. Throughout her career Reynolds worked on igneous intrusions and their associated metamorphism, with particular emphasis on the Newry Igneous Complex in Ireland. In her papers she detailed the sequences of chemical changes that led to granitization which she postulated occurred as a series of ‘fronts’. She argued that these fronts altered the sedimentary rocks through which they passed, eventually turning the sediments into granites or other igneous rocks, depending on the ions carried by the front. In 1939, she married Arthur Holmes; in 1949, she was among the first five women to be elected a Fellow of the Royal Society of Edinburgh, and in 1960 she was awarded the Lyell Medal by the Geological Society of London for her research, her original mind and her refusal to be cowed by the Establishment.

Bridge River tephra: revised distribution and significance for detecting old carbon errors in radiocarbon dates of limnic sediments in southern British Columbia

1980 ◽  
Vol 17 (11) ◽  
pp. 1454-1461 ◽  
Author(s):  
Rolf W. Mathewes ◽  
John A. Westgate
Keyword(s):  
British Columbia ◽  
Sedimentary Rocks ◽  
Lacustrine Sediments ◽  
Igneous Rocks ◽  
The South ◽  
Radiocarbon Dates ◽  
Carbon Contamination ◽  
Horseshoe Lake ◽  
Tephra Beds

Ash-grade Bridge River tephra, identified as such on the basis of shard habit, modal mineralogy, and composition of ilmenite, occurs in sedimentary cores from three lakes located to the south of the previously documented plume and necessitates a significant enlargement of the fallout area of that tephra in southwestern British Columbia.These new, more southerly occurrences are probably equivalent to the ~2350 year old Bridge River tephra, although it can be argued from the evidence at hand that the 14C dates and biotite-rich nature support relationship to a slightly earlier Bridge River event.Large differences exist in the 14C age of sediments immediately adjacent to the Bridge River tephra at these three lake sites; maximum ages of 3950 ± 170 years BP (GX-5549) and 3750 ± 210 years BP (I-10041) were obtained at Phair and Fishblue lakes, respectively, whereas the corresponding age at Horseshoe Lake is only 2685 ± 180 years BP (GX-5757). The two older dates are considered to be significantly affected by old carbon contamination for the bedrock locally consists of calcareous sedimentary rocks and the lacustrine sediments are very calcareous. The 14C date from Horseshoe Lake, which occurs in an area of igneous rocks, appears to be only slightly too old relative to the ~2350 year old Bridge River tephra.Well-dated tephra beds, therefore, can be very useful in assessing the magnitude of old carbon errors associated with radiocarbon dates based on limnic sediments. Calcareous gyttja deposits beneath Bridge River tephra within the study area exhibit old carbon errors of the order of 1350–1550 years.

Interpretation of Pb isotope compositions of galenas from the Midland Valley of Scotland and adjacent regions

1984 ◽  
Vol 75 (2) ◽  
pp. 85-96 ◽  
Author(s):  
John Parnell ◽  
Ian Swainbank
Keyword(s):  
Lower Devonian ◽  
Lead Isotope ◽  
Sedimentary Rocks ◽  
Isotope Ratios ◽  
Igneous Rocks ◽  
Pb Isotope ◽  
Lower Carboniferous ◽  
Granite Magma ◽  
Lower Palaeozoic ◽  
Caledonian Granite

ABSTRACTThe lead isotope compositions of 61 galenas from central and southern Scotland vary markedly between different regions. Most galenas from the southern Grampian Highlands yield isotope ratios (206Pb/204Pb 17·77 ± 0·25, 207Pb/204Pb 15·47 ± 0·05, 208Pb/204Pb 37·63 ± 0·26) less radiogenic than those from Midland Valley galenas (18·22 ± 0·12, 15·55 ± 0·05, 38·13 ± 0·14) whilst galena lead from the Southern Uplands (18·28 ± 0·12, 15·56 ± 0·03, 38·21 ± 0·18) is more radiogenic than that from the southern Midland Valley (18·12 ± 0·06, 15·52 ± 0·02, 38·06 ±0·10). The change in isotopie composition across the Highland Boundary fault reflects the presence or absence of Dalradian rocks which included a magmatic component of lead. Galenas from the Dalradian sequence in Islay, where igneous rocks are lacking, have a composition (18·14±0·04, 15·51±0·01, 37·90±0·02) more like Midland Valley galenas. In the Southern Uplands, galenas yield lead isotope ratios similar to those of feldspars from Caledonian granite (18·30 ± 0·14, 15·57 ± 0·04, 37·96 ± 0·15) analysed by Blaxland et al. (1979). The similar ratios reflect the incorporation of Lower Palaeozoic sedimentary rocks into the granite magma, rather than a granitic source for the mineralisation. The granites were then thermal-structural foci for later mineralising fluids which leached metals from the surrounding rocks. Within the Midland Valley, galenas hosted in Lower Devonian-Lower Carboniferous lavas are notably more radiogenic (18·31 ±0·12, 15·58 ± 0·06, 38·20 ± 0·16) than sediment-hosted galenas (18·14 ± 0·07, 15·52 ± 0·02, 38·08 ± 0·10). The Devonian lavas at least may have inherited lead from subducted (? Lower Palaeozoic) rock incorporated in the primary magma.

Late Mesozoic—Cenozoic clay mineral successions of southern Iran and their palaeoclimatic implications

Clay Minerals ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 191-203 ◽  
Author(s):  
F. Khormali ◽  
A. Abtahi ◽  
H. R. Owliaie
Keyword(s):  
Electron Microscopy ◽  
Upper Cretaceous ◽  
Sedimentary Rocks ◽  
X Ray Diffraction ◽  
Humid Climate ◽  
X Ray ◽  
Late Mesozoic ◽  
Southern Iran ◽  
Transmission Electron

AbstractClay minerals of calcareous sedimentary rocks of southern Iran, part of the old Tethys area, were investigated in order to determine their origin and distribution, and to reconstruct the palaeoclimate of the area. Chemical analysis, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and thin-section studies were performed on the 16 major sedimentary rocks of the Fars and Kuhgiluyeh Boyerahmad Provinces.Kaolinite, smectite, chlorite, illite, palygorskite and illite-smectite interstratified minerals were detected in the rocks studied. The results revealed that detrital input is possibly the main source of kaolinite, smectite, chlorite and illite, whilein situneoformation during the Tertiary shallow saline and alkaline environment could be the dominant cause of palygorskite occurrences in the sedimentary rocks.The presence of a large amount of kaolinite in the Lower Cretaceous sediments and the absence or rare occurrence of chlorite, smectite, palygorskite and illite are in accordance with the warm and humid climate of that period. Smaller amounts of kaolinite and the occurrence of smectite in Upper Cretaceous sediments indicate the gradual shift from warm and humid to more seasonal climate. The occurrence of palygorskite and smectite and the disappearance of kaolinite in the late Palaeocene sediments indicate the increase in aridity which has probably continued to the present time.

ANALYSIS OF LANDSLIDE PROCESSES ON THE ROADS OF KHAKASSIA BEFORE THE BRIDGES OVER THE YENISEI RIVER FROM THE PERSPECTIVE OF ALL STAGES OF THE LIFE CYCLE OF STRUCTURES

2020 ◽  
Author(s):  
Олег Закирович Халимов
Keyword(s):  
Life Cycle ◽  
Design Stage ◽  
Yenisei River ◽  
The Road ◽  
Road Section ◽  
Hydrogeological Conditions ◽  
First Case ◽  
Landslide Processes ◽  
The Yenisei River ◽  
Hydrogeological Studies

В статье проанализированы трудности в процессе строительства автомобильной дороги от Братского моста через Енисей в сторону Абакана, связанные с отсутствием учета на стадии проектирования осложнившихся гидрогеологических условий, влияющих на опускание моста и дороги. Оползневые процессы, созданные искусственно при сооружении выемки дна автомобильной дороги от Братского моста более 40 лет развиваются на участке дороги Абакан-Подсинее перед железным и автодорожным мостом через Енисей. Как и в первом случае на стадии проектирования не выполнены гидро-геологические исследования. The article analyzes the difficulties in the process of construction of the highway from the Bratsk bridge over the Yenisei river to Abakan, associated with not taking into account the complicated hydrogeological conditions at the design stage, associated with the lowering of the bridge and road. Landslide processes created artificially during the construction of the dredging of the road bottom from the Bratsk bridge have been developing for more than 40 years on the Abakan-Podsinee road section in front of the railway and road bridge over the Yenisei. As in the first case, hydrogeological studies were not performed at the design stage.

Triassic and Pleistocene Surfaces on some Leicestershire Igneous Rocks

1934 ◽  
Vol 71 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Frank Raw
Keyword(s):  
Sedimentary Rocks ◽  
Igneous Rocks ◽  
Glacial Deposits ◽  
Small Areas ◽  
South West

The ancient rocks of Leicestershire may be taken to comprise the pre-Cambrian volcanic and sedimentary rocks of Charnwood Forest, and the igneous rocks intrusive into them, viz. the dacite-porphyrites of Bardon Hill, Peldar, and High Sharpley, etc., the granophyric diorites and porphyrites within and south-west of the Forest and in South Leicestershire, and the Mountsorrel granite or granodiorite. There is reason to believe that all except the last are pre-Cambrian in age: for the last a post-Silurian age seems most probable. These ancient rocks are now exposed through the removal of the Keuper Marl, whichhad largely if not completely buried them. In glacial times, however, small areas have been reburied under glacial deposits.

scholarly journals PENGARUH KEMACETAN DI SIMPANG SABILILLAH TERHADAP IMPLEMENTASI CITRA LALU LINTAS DI SIMPANG PROGRESIF

2015 ◽  
Vol 9 (2) ◽  
pp. 114
Author(s):  
Supiyono, Dwi Ratnaningsih, Rudy Ariyanto
Keyword(s):  
Road Traffic ◽  
Flame Length ◽  
Traffic Volume ◽  
Signalized Intersections ◽  
Degree Of Saturation ◽  
The Road ◽  
Road Section ◽  
On The Road ◽  
High Traffic Volume

Progress of a country in line with the progress of traffic (transport). Fluency in traffic is determined by the smoothness of traffic on the road. Problems often arise on the highway is congestion at the intersection. Neither was signalized intersections and signalized intersections. Problems at the intersection is less accuracy green flame at the intersection with the number of vehicles in a segment. A road with high traffic volume vehicle green flame low while other road traffic volume small green flame length. So in a long queue roads, while other roads are deserted while still green flame.     This study aims to minimize the occurrence of conflic at the intersection of green flame. Research will make iterations in the intersection, where a road section which will be nominated densely green flame, the flame of the green according to the volume of traffic on these roads. Each road will be a green flame in accordance with the volume of traffic, without having to change any program there is a change in traffic volume.The degree of saturation of the calculation obtained by ....Keywords: roads, hight traffic, progressive intersection, degree saturation

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