PLATE TECTONICS IN PORTUGUESE AND SPANISH SCIENCE TEXTBOOKS: FROM THE 1960s TO THE 1980s

2021 ◽  
Vol 40 (2) ◽  
pp. 538-565
Author(s):  
BENTO CAVADAS
Keyword(s):  
Plate Tectonics ◽  
Magnetic Anomalies ◽  
Seafloor Spreading ◽  
Transform Faults ◽  
Science Textbooks ◽  
Didactic Transposition ◽  
Basaltic Rocks ◽  
Spanish Science ◽  
The 1960S ◽  
Seafloor Sediments

Plate tectonics caused a revolution within earth sciences which then was transposed into science textbooks. The main objective of this paper is to explore how plate tectonics influenced Portuguese and Spanish science textbooks published from the 1960s through the 1980s. For this purpose, a qualitative method based on the concept of didactic transposition is used. The didactic transposition of seafloor spreading evidence such as ridges, rifts and trenches, transform faults, seafloor sediments, the age of seafloor basaltic rocks, the magnetic anomalies on the seafloor, the Benioff zones and the subduction process, and also the didactic transposition of the formation of mountains ranges and island arcs, convection currents, plate tectonics concepts, boundaries and motion, and plate tectonics acceptance are studied in a comprehensive sample of science textbooks. The analysis of textbooks shows that the didactic transposition of seafloor spreading, and plate tectonics started mainly in 1970s Portuguese and Spanish textbooks and had a strong development in 1980s textbooks. No major differences were found between the approaches to plate tectonics in similar age Portuguese and Spanish textbooks. At the beginning of the 1970s, textbooks presented partial evidence for seafloor spreading, such as magnetic anomalies and the characteristics of ridges, rifts and trenches. They also addressed convection currents but only those that were related to geosynclines. In the mid 1970s and in the 1980s, textbooks presented more comprehensive evidence of seafloor spreading, by adding didactical transpositions of transform faults, seafloor sediments and the age of seafloor rocks. They also presented in more detail topics such as magnetic anomalies, the Benioff zones, orogenic processes and the tectonic significance of ridges, rifts and trenches. Plate tectonic theory was presented in major textbooks as widely accepted, and discussions about speculative facts or processes were rare.

scholarly journals Initiation of a Proto-transform Fault Prior to Seafloor Spreading

2020 ◽  
Author(s):  
Finnigan Illsley-Kemp ◽  
JM Bull ◽  
D Keir ◽  
T Gerya ◽  
C Pagli ◽  
...  
Keyword(s):  
Plate Tectonics ◽  
Seafloor Spreading ◽  
Continental Rift ◽  
Formation Mechanisms ◽  
Transform Fault ◽  
Transform Faults ◽  
Local Seismicity ◽  
Ocean Ridges ◽  
Rifted Margins ◽  
Direct Observations

©2018. The Authors. Transform faults are a fundamental tenet of plate tectonics, connecting offset extensional segments of mid-ocean ridges in ocean basins worldwide. The current consensus is that oceanic transform faults initiate after the onset of seafloor spreading. However, this inference has been difficult to test given the lack of direct observations of transform fault formation. Here we integrate evidence from surface faults, geodetic measurements, local seismicity, and numerical modeling of the subaerial Afar continental rift and show that a proto-transform fault is initiating during the final stages of continental breakup. This is the first direct observation of proto-transform fault initiation in a continental rift and sheds unprecedented light on their formation mechanisms. We demonstrate that they can initiate during late-stage continental rifting, earlier in the rifting cycle than previously thought. Future studies of volcanic rifted margins cannot assume that oceanic transform faults initiated after the onset of seafloor spreading.

FROM THE CONTRACTING EARTH TO CONTINENTAL DRIFT: WEGENER'S INFLUENCE ON PORTUGUESE AND SPANISH SCIENCE TEXTBOOKS THROUGH THE TWENTIETH CENTURY

2019 ◽  
Vol 38 (1) ◽  
pp. 74-93
Author(s):  
BENTO CAVADAS
Keyword(s):  
Twentieth Century ◽  
Qualitative Method ◽  
Gravitational Force ◽  
Continental Drift ◽  
Historical Research ◽  
The Moon ◽  
Science Textbooks ◽  
Didactic Transposition ◽  
The Earth ◽  
Spanish Science

ABSTRACT Alfred Wegener's work on continental drift profoundly influenced the development of geology during the twentieth century. The main objective of this historical research is to explore how Wegener's hypothesis about the origin of continents and oceans influenced Portuguese and Spanish science textbooks published in the twentieth century. For this purpose, a qualitative method based on the Chevallard's concept of didactic transposition was used. The didactic transposition of the fundamentals of continental drift, including displacements forces and geographical, geophysical, geological, paleontological, biological, and paleoclimatic arguments used by Wegener to support this hypothesis, was studied in a comprehensive sample of twenty science textbooks published after the publication of Die Entstehung der Kontinente und Ozeane (Wegener 1915). The analysis of textbooks shows that the didactic transposition of continental drift was commonly present in Portuguese and Spanish textbooks beginning in the 1930s, although, with different degrees of development. Science textbooks since the 1950s presented the displacement forces of sial continental blocks proposed by Wegener, namely the centrifugal force of Earth's rotation and the attractive gravitational force that results from the interaction of the earth with the moon and sun. The geographical, geological, paleontological and biological arguments supporting continental drift were commonly addressed in many science textbooks, followed by the paleoclimatic arguments. The geophysical arguments were briefly addressed in only two textbooks. Many Portuguese and Spanish textbooks also presented critiques of Wegener's work, mainly focused on the lack of explanation for the origin and nature of forces that could move continents at the Earth's surface.

scholarly journals Initiation of a Proto-transform Fault Prior to Seafloor Spreading

2020 ◽  
Author(s):  
Finnigan Illsley-Kemp ◽  
JM Bull ◽  
D Keir ◽  
T Gerya ◽  
C Pagli ◽  
...  
Keyword(s):  
Plate Tectonics ◽  
Seafloor Spreading ◽  
Continental Rift ◽  
Formation Mechanisms ◽  
Transform Fault ◽  
Transform Faults ◽  
Local Seismicity ◽  
Ocean Ridges ◽  
Rifted Margins ◽  
Direct Observations

©2018. The Authors. Transform faults are a fundamental tenet of plate tectonics, connecting offset extensional segments of mid-ocean ridges in ocean basins worldwide. The current consensus is that oceanic transform faults initiate after the onset of seafloor spreading. However, this inference has been difficult to test given the lack of direct observations of transform fault formation. Here we integrate evidence from surface faults, geodetic measurements, local seismicity, and numerical modeling of the subaerial Afar continental rift and show that a proto-transform fault is initiating during the final stages of continental breakup. This is the first direct observation of proto-transform fault initiation in a continental rift and sheds unprecedented light on their formation mechanisms. We demonstrate that they can initiate during late-stage continental rifting, earlier in the rifting cycle than previously thought. Future studies of volcanic rifted margins cannot assume that oceanic transform faults initiated after the onset of seafloor spreading.

Marie Tharp: Seafloor mapping and ocean plate tectonics

2020 ◽  
Author(s):  
Mathilde Cannat ◽  
Deborah Smith ◽  
Daniel Fornari ◽  
Vicki Ferrini ◽  
Javier Escartin
Keyword(s):  
Plate Tectonics ◽  
Essential Element ◽  
Central Valley ◽  
Fracture Zones ◽  
Transform Faults ◽  
Seafloor Mapping ◽  
Mid Ocean Ridge ◽  
The 1960S ◽  
Ocean Ridge ◽  
Central Atlantic

<p><span>The pioneering seafloor mapping by Marie Tharp played a key role in the acceptance of the plate tectonic theory. Her physiographic maps,  published with Bruce Heezen,  covered the Earth’s oceans and revealed with astonishing accuracy the submarine landscape. She exposed the full extent of the global mid-ocean ridge system, documented features such as seamounts and volcanic chains, trenches, and transform faults. Marie Tharp co-authored the first papers describing the major fracture zones in the Central Atlantic (Chain, Romanche, Vema). In 1952, she also discovered that the Atlantic ridge has a central valley (the axial valley), and convinced her colleague Bruce Heezen that it, which corresponds to sustained seismicity (highlighted by other researchers at the same time thanks to the worldwide networking of seismological stations), is a rift that separates the eastern and western provinces of the Atlantic Ocean. Tharp and Heezen were not yet talking about plate tectonics at this time. But when, at the beginning of the 1960s, the first magnetic anomaly maps showed that the oceans were "young", and that the age of the seabed increased with the distance from the ridges, their physiographic map became an essential element in understanding the role that these ridges play, as well as the distribution of the main current terrestrial plates. In this poster, we present original maps and sketches that document this key contribution to the understanding of the Earth's tectonics.</span></p>

The Paving Stone Theory of World Tectonics

2018 ◽  
Author(s):  
Roy Livermore
Keyword(s):  
Indian Ocean ◽  
Plate Tectonics ◽  
Earth Science ◽  
Transform Faults ◽  
Plate Motions ◽  
Euler’S Theorem ◽  
History Of ◽  
New Ideas ◽  
Entire History ◽  
The Indian Ocean

Tuzo Wilson introduces the concept of transform faults, which has the effect of transforming Earth Science forever. Resistance to the new ideas is finally overcome in the late 1960s, as the theory of moving plates is established. Two scientists play a major role in quantifying the embryonic theory that is eventually dubbed ‘plate tectonics’. Dan McKenzie applies Euler’s theorem, used previously by Teddy Bullard to reconstruct the continents around the Atlantic, to the problem of plate rotations on a sphere and uses it to unravel the entire history of the Indian Ocean. Jason Morgan also wraps plate tectonics around a sphere. Tuzo Wilson introduces the idea of a fixed hotspot beneath Hawaii, an idea taken up by Jason Morgan to create an absolute reference frame for plate motions.

Seafloor spreading magnetic anomalies in the southeastern Arabian Sea

1995 ◽  
Vol 128 (1-2) ◽  
pp. 105-114 ◽  
Author(s):  
A.K. Chaubey ◽  
G.C. Bhattacharya ◽  
D.Gopala Rao
Keyword(s):  
Arabian Sea ◽  
Magnetic Anomalies ◽  
Seafloor Spreading ◽  
Southeastern Arabian Sea

Oceanic plateau formation by seafloor spreading implied by Tamu Massif magnetic anomalies

2019 ◽  
Vol 12 (8) ◽  
pp. 661-666 ◽  
Author(s):  
William W. Sager ◽  
Yanming Huang ◽  
Masako Tominaga ◽  
John A. Greene ◽  
Masao Nakanishi ◽  
...  
Keyword(s):  
Magnetic Anomalies ◽  
Seafloor Spreading ◽  
Oceanic Plateau ◽  
Tamu Massif

Drummond Hoyle Matthews. 5 February 1931 — 20 July 1997

1999 ◽  
Vol 45 ◽  
pp. 275-294
Author(s):  
Robert S. White
Keyword(s):  
Graduate Student ◽  
Plate Tectonics ◽  
Seafloor Spreading ◽  
Marine Geophysics ◽  
Scientific Legacy ◽  
The World ◽  
Work Done

Drummond (Drum) Matthews was a leader who gave himself selflessly for the good of his students and science. He is best known for his work with Fred Vine (F.R.S. 1974), then his graduate student, on the seafloor spreading hypothesis, which underpinned the plate tectonics revolution, and for the work done under his leadership by the Cambridge marine geophysics group and the British Institutions' Reflection Profiling Syndicate (BIRPS). But perhaps his most enduring scientific legacy lies in his many former students, now in positions of leadership and responsibility around the world, who continue to make significant contributions to the health of science.

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