Magmatic and Hydrothermal Controls on the Mineralogy of the Basal Zone, Nechalacho REE-Nb-Zr Deposit, Canada☼

2017 ◽  
Vol 112 (8) ◽  
pp. 1823-1856 ◽  
Author(s):  
Volker Möller ◽  
Anthony E. Williams-Jones
Keyword(s):  
Basal Zone

scholarly journals Preliminary results of tritium analyses in basal ice, Matanuska Glacier, Alaska, U.S.A.: evidence for subglacial ice accretion

1996 ◽  
Vol 22 ◽  
pp. 126-133 ◽  
Author(s):  
Jeffrey C. Strasser ◽  
Daniel E. Lawson ◽  
Grahame J. Larson ◽  
Edward B. Evenson ◽  
Richard B. Alley
Keyword(s):  
Drainage System ◽  
Supercooled Water ◽  
Ice Formation ◽  
Flowing Water ◽  
Ice Accretion ◽  
Preliminary Results ◽  
Basal Ice ◽  
Basal Zone ◽  
Matanuska Glacier ◽  
Initial Results

The stratified-facies ice of the basal zone of Matanuska Glacier, Alaska. U.S.A., contains significant concentrations of anthropogenic tritium, whereas unaltered englacial-zone ice is devoid of tritium. Supercooled water flowing through subglacial conduits during the melt season likewise contains tritium, as does frazil and other platy ice that nucleates and grows within this subglacially flowing water. These initial results demonstrate net accretion of more than 1.4 m of stratified basal-zone ice since initiation of above-ground, thermonuclear bomb testing in 1952. Furthermore, these results support a theory of basal ice formation by ice accretion and debris entrainment from supercooled water within a distributed subglacial drainage system.

scholarly journals Activation of rape (Brassica napus L.) embryo during seed germination. V. The first zones of ultrastructural changes and their expansion

2014 ◽  
Vol 56 (1) ◽  
pp. 77-91 ◽  
Author(s):  
Mieczysław Karaś
Keyword(s):  
Brassica Napus ◽  
Seed Germination ◽  
Seed Coat ◽  
Basal Part ◽  
Ultrastructural Changes ◽  
Embryo Axis ◽  
Brassica Napus L ◽  
Root Cells ◽  
Basal Zone

In the germinating rape embryo the columella and basal part of hypocotyl undergo earliest activation. Its first ultrastructural symptom is the appearance of numerous ER vesicles after 3-6 h of seed swelling. Their number is the highest in the external layers of the columella and decreases in basipetal direction. Dermatogen cells in the basal zone of the hypocotyl contain the greatest amount of ER structures, whereas decreasing amounts are found in both directions along the embryo axis and centripetally. Further changes in the ER spread in a similar order. The vesicles merge and form a tubular and plate-like ER. Then, they disappear and are replaced by tubular and vesicular forms. The changes in the ER are gradually followed by ultrastructural symptoms of activation of mitochondria, plastids and dictyosomes. The highest number of ER structures and other organelles accumulate in root cells shortly before piercing of the seed coat. After germination their amount decreases and remains almost stable.

Genesis of carbonate till in the lee sides of Precambrian Shield uplands, Hemlo area, Ontario

1987 ◽  
Vol 24 (10) ◽  
pp. 2004-2015 ◽  
Author(s):  
Stephen R. Hicock
Keyword(s):  
Ice Sheet ◽  
Glacial Maximum ◽  
Laurentide Ice Sheet ◽  
The South ◽  
Precambrian Shield ◽  
Basal Zone ◽  
Compressive Flow ◽  
Late Wisconsinan ◽  
Basal Till

Near Hemlo, Ontario, highly calcareous till is confined to areas located downglacier from Precambrian uplands, at least 150 km from the Paleozoic–Precambrian boundary. It comprises subglacial meltout till between lodgment tills, and the calcareous package overlies noncalcareous basal till (not studied) and underlies noncalcareous supraglacial meltout till. The tills can be distinguished by textural, carbonate, and clast compositions. Glaciotectonic deformations, stone fabrics and striae, and stone provenance from the tills, as well as erosional and depositional landforms, indicate that ice advanced to the south–southwest across bedrock contacts and over Precambrian uplands.Deposition of all five tills can be explained with one glacial event. As the Late Wisconsinan margin of the Laurentide ice sheet advanced against uplands about 20 km northeast of Hemlo it experienced compressive flow while depositing the non calcareous basal till. Upshearing of stoss-side local debris high into the ice also occurred as englacial ice overrode the slowed basal zone. Once over the upland, englacial ice assumed extending flow, and downshearing of distal debris, which was deposited as calcareous lodgment till on the lee sides of uplands. After the glacial maximum, the glacier ceased internal movement and subglacial meltout till was laid down. A late reactivation of the ice deposited the upper lodgment till and final stagnation formed the supraglacial meltout till.

scholarly journals Preliminary results of tritium analyses in basal ice, Matanuska Glacier, Alaska, U.S.A.: evidence for subglacial ice accretion

1996 ◽  
Vol 22 ◽  
pp. 126-133 ◽  
Author(s):  
Jeffrey C. Strasser ◽  
Daniel E. Lawson ◽  
Grahame J. Larson ◽  
Edward B. Evenson ◽  
Richard B. Alley
Keyword(s):  
Drainage System ◽  
Supercooled Water ◽  
Ice Formation ◽  
Flowing Water ◽  
Ice Accretion ◽  
Preliminary Results ◽  
Basal Ice ◽  
Basal Zone ◽  
Matanuska Glacier ◽  
Initial Results

The stratified-facies ice of the basal zone of Matanuska Glacier, Alaska. U.S.A., contains significant concentrations of anthropogenic tritium, whereas unaltered englacial-zone ice is devoid of tritium. Supercooled water flowing through subglacial conduits during the melt season likewise contains tritium, as does frazil and other platy ice that nucleates and grows within this subglacially flowing water. These initial results demonstrate net accretion of more than 1.4 m of stratified basal-zone ice since initiation of above-ground, thermonuclear bomb testing in 1952. Furthermore, these results support a theory of basal ice formation by ice accretion and debris entrainment from supercooled water within a distributed subglacial drainage system.

Interpretation d'une succession interessant la limite oligo-miocene dans le sud du Bordelais

1963 ◽  
Vol S7-V (6) ◽  
pp. 980-988
Author(s):  
Michelle Caralp ◽  
Jean Moyes ◽  
Chantal Puechmaille ◽  
Michel Vigneaux
Keyword(s):  
Intermediate Zone ◽  
Basal Zone ◽  
Ostracod Species

Abstract A core drilled at Salles, southwest of Bordeaux (France), yielded a section of strata which embraces the Oligocene-Miocene boundary. The beds are principally limestones with a predominance of carbonates in opposition to small amounts of detrital elements. On the basis of the frequency of the fauna included in the limestones three sedimentary zones are distinguished. The basal zone contains allochemical components suggesting calm sedimentation and includes nummulites and abundant melobesiids. The intermediate zone has faunal and lithologic characteristics of both the underlying and overlying zones. In the upper zone Miogypsinoides fades out and glauconite and pyrite appear. Examination of the foraminifera and ostracod microfaunas reveals three biozones which correspond to the sedimentary zones. Two tables give the distribution of the principal foraminifera and ostracod species. The type of sediments and the distribution of the microfaunas indicate that the basal zone is Oligocene, the upper zone is Miocene and the intermediate zone marks the top of the Oligocene.

Inner ear pathology in osteogenesis imperfecta congenita

1980 ◽  
Vol 94 (7) ◽  
pp. 697-705 ◽  
Author(s):  
Makoto Igarashi ◽  
Austin I. King ◽  
C. Willy Schwenzfeier ◽  
Tsuneo Watanabe ◽  
Bobby R. Alford
Keyword(s):  
Osteogenesis Imperfecta ◽  
Inner Ear ◽  
Temporal Bone ◽  
Middle Ear ◽  
Stria Vascularis ◽  
Bony Labyrinth ◽  
Congenital Form ◽  
Basal Zone ◽  
Ear Ossicles ◽  
Osteogenesis Imperfecta Congenita

AbstractThis temporal bone report describes the inner ear deformities which were found in addition to the bony pathology in a case of osteogenesis imperfecta congenita. The labyrinthine pathology includes anomalously positioned and enlarged vestibular spaces, the existence of a scala communis (on one side) and the existence of hematoxylin dark-stained material in the basal zone of the stria vascularis.The appearance of temporal bone reports of osteogenesis imperfecta congenita is sporadic. Friedmann (1974)described changes in the bony capsule in one case of osteogenesis imperfecta congenita Zajtchul and Lindsay(1975)reported three cases of the congenital form of osteogenesis imperfecta with their temporal bone findings. Within recent years, Altmann reported three cases in 1962, Bretlau and Jorgensen reported one case in 1969, Bergstrom and others reported one case in 1972, and Bergstrom described the temporal bone findings in four infants in 1977. The pathologic description of the temporal bone in osteogenesis imperfecta congenita has been focused more or less on the structures of the bony labyrinth and the middle ear ossicles, with a brief description of the inner ear. In this report, we describe anomalous inner ear structures in osteogenesis imperfecta congenita.

scholarly journals The gynoecium structure in Dracaena fragrans (L.) Ker Gawl., Sansevieria parva N.E. Brown and S. trifasciata Prain (Asparagaceae) with special emphasis on the structure of the septal nectary

2014 ◽  
Vol 66 (4) ◽  
pp. 55-64 ◽  
Author(s):  
Anastasiya Odintsova ◽  
Oksana Fishchuk ◽  
Aneta Sulborska
Keyword(s):  
Basal Zone ◽  
Septal Nectary ◽  
The Common ◽  
Vertical Zonality

In the gynoecium of <em>Dracaena fragrans</em>, <em>Sansevieria</em> <em>parva </em>and <em>S. trifasciata</em>, the vertical zonality of the ovary, the structural zonality of the gynoecium following Leinfellner, and the zonality of the septal nectary were studied. The ovary structure is characterised by a high parenchymatous ovary base and ovary roof as well as a long septal nectary that can be extended in both of them and opens with secretory nectary splits. The gynoecium of these species has a short synascidiate zone, a fertile hemisynascidiate zone with a median ovule attached, a hemisymlicate zone (only in <em>D. fragrans</em>) and an asymplicate zone (with postgenitally fused carpels) that comprises the ovary roof, common style and stigma. In the septal nectary, we detected three vertical zones: the basal zone of the distinct nectary in the ovary base or/and the synascidiate zone, the zone of the common nectary (in the hemisynascidiate and hemisymlicate zones) and the zone of the external nectary (the nectary splits in the asymplicate zone). The gynoecium structure in the studied species shows differences in the length of the gynoecium and septal nectary zones and also in the interrelationships of all these three types of vertical zonality.

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