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direction of coiling

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Journal Article
Published: 01 October 1957
Micropaleontology (1957) 3 (4): 393-397.
...Yedatore Nagappa Abstract "Changes in the direction of coiling noted throughout the time-range of certain pelagic foraminifera can be used in stratigraphic correlation. Such changes have also been noted in a species of Globorotalia occurring commonly in west Pakistan, in which an abrupt change from...
Journal Article
Published: 01 November 2003
Journal of Micropalaeontology (2003) 22 (2): 141-146.
... variations (as inferred from stable isotope analyses of foraminifer shells). Accordingly, coiling direction was proportional or biased to sinistral. 14 5 2002 10 5 2003 © 2003 The Micropalaeontological Society 2003 The percentage of Globigerina bulloides sinistral ranges from...
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Journal Article
Journal: Geology
Published: 01 May 1976
Geology (1976) 4 (5): 305-309.
...Tsunemasa Saito Abstract Systematic changes with time in the coiling direction of the planktonic fora-miniferal genus Pulleniatina provide useful datum levels for interregional correlation of Pliocene-Quaternary marine sediments. The pattern of coiling-direction changes was concordant throughout...
Journal Article
Journal: AAPG Bulletin
Published: 01 October 1965
AAPG Bulletin (1965) 49 (10): 1760.
...Betty J. Enbysk ABSTRACT Coiling direction ratios of Globigerina pachyderma (Ehrenberg) plotted for sediment surface samples from the northeastern Pacific north of 40°N. did not show the consistent relationship which would recommend them as reliable guides for deep-sea core analysis in this region...
Journal Article
Published: 01 July 1960
Journal of Paleontology (1960) 34 (4): 671-681.
...Orville Lee Bandy Abstract Studies of Recent populations of the planktonic foraminifer, Globigerina pachyderma (Ehrenberg), show that more than 98% of Arctic and Antarctic specimens coil in a counter-clockwise direction (sinistral), whereas populations in temperate and tropical regions are mostly...
Journal Article
Journal: Paleobiology
Published: 01 January 2001
Paleobiology (2001) 27 (2): 327-347.
... ). There are several cases where the details of phylogeny do matter primarily because they represent instances where there may have been a change in coiling direction at the evolution of a new group. The origins of dextral “ Morozovella ” spinulosa and its descendants are commonly assumed to lie in sinistral...
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Journal Article
Journal: Paleobiology
Published: 01 January 2000
Paleobiology (2000) 26 (2): 238-257.
... existence remains controversial ( Okamoto 1988 ; Ackerly 1989a , b ; Illert 1989 ; Savazzi 1990 ). Despite this, it is the implicit reference of “fixed axis” models. At present there is no single method to locate the coiling axis. It can be roughly estimated, in some cases, by the columella direction...
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Series: GCSSEPM
Published: 01 December 2012
DOI: 10.5724/gcs.12.32.0133
EISBN: 978-0-9836097-8-0
... pinch-outs. This methodology utilizes standard biostratigraphic information (i.e. regional extinction events, paleoecology, and abundance/diversity profiles) coupled with coiling direction reversals ( i.e., G. menardii, G. humerosa ), size changes ( i.e., G. menardii ), individual abundance increases...
Journal Article
Journal: Geophysics
Published: 26 March 2019
Geophysics (2019) 84 (3): E143-E154.
... winding directions on the TX coil plane. This arrangement avoids the loss of the transmission magnetic moment, and it does not cancel out the magnetic linkage of the secondary field. More importantly, the proposed crossing-loop coil design provides better near-surface exploration performance as a small...
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Image
<b>Coiling</b> <b>direction</b> of  Globigerina bulloides  in ( a ) the Gliwice 19 and ( ...
Published: 01 November 2003
Fig. 2. Coiling direction of Globigerina bulloides in ( a ) the Gliwice 19 and ( b ) Gliwice 24 sections.
Journal Article
Journal: Geophysics
Published: 18 July 2018
Geophysics (2018) 83 (5): D165-D171.
... logging-while-drilling (LWD) tool for geosteering applications. The directional LWD tool is equipped with a joint-coil antenna composed of an axially polarized coil Rz connected in series with two transversely polarized coils Rx. During a revolution around the axis of the tool, the voltage of the axial...
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Image
Figure  10. Counts of <b>coiling</b> <b>directions</b> in 8 early Danian and 14 upper Maa...
Published: 01 January 2001
Figure 10. Counts of coiling directions in 8 early Danian and 14 upper Maastrichtian species. Counts of dextral individuals shown in solid columns, those for sinistral individuals in open columns. Danian species (both trochospiral and microperforate) display approximately proportionate coiling
Journal Article
Journal: Geophysics
Published: 22 January 2007
Geophysics (2007) 72 (2): F45-F56.
... sensitivity footprint is defined, based on the at-surface behavior of the sensitivity distribution, simply as the area where the sensitivity is at least 10% of its maximum value. For the vertical coaxial (VCA) coil configuration, the size of the sensitivity footprint in the y -direction (perpendicular...
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Journal Article
Journal: Geophysics
Published: 28 September 2018
Geophysics (2018) 83 (6): E371-E383.
... (SQUID)-based magnetic-field receivers used for TEM have quantitative advantages and higher sensitivity compared with commonly used induction coils. Special applications are deep soundings with target depths > 1 km and settings with conductive overburden. However, SQUIDs have rarely been applied...
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Journal Article
Published: 01 May 2010
Journal of Paleontology (2010) 84 (3): 444-465.
... viewed from the exterior and is much larger than the RV ( Skelton and Smith, 2000 ; Gourrat et al., 2003 ). This coiling direction is opposite to the opisthogyrate counter-clockwise LV-AV of oysters such as Exogyra , which has been noted by many rudist specialists (see Malchus, 1995 ). Two end...
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Journal Article
Journal: Geophysics
Published: 01 January 2002
Geophysics (2002) 67 (3): 739-745.
... HTS SQUIDs have been developed and tested in numerous field trials. In this paper, the reliability of SQUID TEM data is investigated by comparison with commonly used induction-coil data. Generally, a good agreement between SQUID and coil TEM data was found. However, two effects were observed...
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Series: Society of Exploration Geophysicists Geophysical References Series
Published: 01 January 1989
EISBN: 9781560802662
... Abstract The current development and direction of the airborne electromagnetic (AEM) method in China are briefly reviewed. Experience in developing the frequency-domain airborne electromagnetic systems (FAEM) is introduced. Technical problems encountered in developing FAEM systems...
Image
Figure  1. Method of determining the orientation of the <b>coiling</b> axis in a s...
Published: 01 January 2003
Figure 1. Method of determining the orientation of the coiling axis in a specimen. The commissure of the shell was set on the x - y plane with the beak on the origin of the coordinate system and with the hinge line along the x -axis (A). The directions of the normal unit vectors
Image
Figure  1. Examples of ammonites with zigzag <b>coiling</b>. A,  Catacoeloceras  s...
Published: 01 January 2002
displacement, the whorl coiled with a zigzag periodicity of some three-quarters of a whorl; ribs are initially slightly oblique to the growth direction and gradually revert to perpendicular. J, Strajevskia sp., PA8212; the specimen displays extreme rightward deviation (epizoan now absent) and a zigzag cycle
Journal Article
Journal: Geology
Published: 01 October 1978
Geology (1978) 6 (10): 630-634.
... Pliocene biogeographic events: (1) great abundance of sinistral coiling Neogloboquadrina pachyderma at 4.3 m.y. ago at site 157 and 0.7 m.y. later at site 154A, and (2) a sinistral-to-dextral change in the coiling-direction preference in Pulleniatina 3.5 m.y. ago at both locations. Identification...