Geologists must be able to “read” a geological map. That means interpreting the vertical dimension through the 2D view represented on the map and at different scales. The main objective of this book is to help students during this difficult learning process. Based on an abundant iconography (field photos, maps, cross-sections) and on basics in mathematics and mechanics, the book dissects the geometry of emblematic geological structures and objects in order to build 3 D models, printable in 3D. The book is dedicated to structural geology with a particular emphasis on kinematics of faulting and folding and on salt tectonics (chapters III, IV and V). The origin of continental great unconformities and oceanic break-up unconformities is also discussed (chapter II).
The audience of the book is broad and includes (under)graduate students in Earth Sciences, professors of Natural Sciences, and professional or amateur geologists.
Table of Contents
1 Geology, a story of layers
1.1 The globe and the various layers that make it up
1.2 Strike and dip of a layer
1.3 Geometric relationships between dip and topography using the three points method
1.4 3D models of layers intersecting a topography
Information box: valley morphology
2 When strata cross and overlie each other: the concept of unconformity
2.1 Definition and historical importance of the concept of unconformity
Information box: geological time and philosophy
2.2 Overview of unconformities, the concept of basement and cover, great regional unconformities
2.3 Great ocean unconformities, the concept of a "break-up unconformity"
2.4 Dating an unconformity
2.5 Dating the duration of an event
2.6 Unconformity model for 3D printing
3 When strata fracture: faults
3.1 Fracture theory (Mohr’s circle and envelope)
Information box: triaxial stress condition
Information box: when rocks fracture in other ways
3.2 The main categories of faults
3.3 The consequences of movement on faults
3.4 Elemental structures resulting from combinations of faults
3.5 Printable 3D models of faults and associations of faults
4 When strata fold without breaking too much: detachment folds
4.1 Theory of folding
4.2 Some basic concepts relating to folds 56 Information box: relationships between folds and cleavage
4.3 Horizontal shortening, excess surface area and detachment depth: toward the kinematics of detachment folds
4.4 3D models of detachment folds
4.5 The role of the basement: "thin-skinned" tectonics and "thick-skinned" tectonics
5 When folds and faults interact: fault-related folds and fold-and-thrust belts
5.1 The concept of fault-bend folding
5.2 Kinematics of fault-bend folding
5.3 Fault-propagation folding: geometry and kinematics
5.4 Variations and limits of kinematic models of fault-bend folds
5.5 3D models of fault-bend folds 88 Information box: folding of strata and analog models
5.6 Interaction of individual structures in fold-and-thrust belts
6 When the salt plays the major role: the effects of salt activity and the concept of salt tectonics
6.1 Deposition of salt and geodynamics
6.2 Definition of the different types of salt-related structures
6.3 Causes of salt mobility
6.4 Printable 3D models of salt-related structures
Practical tips for designing and printing 3D objects
Toward 3D models representing real examples
Other applications in the field of earth sciences
Dominique Frizon de Lamotte, emeritus professor, is the founder (in 1991) of the Department of Geosciences and Environment at the University of Cergy-Pontoise (now CY Cergy Paris Université). As a structural geologist, his field of expertise is the sedimentary basins from their formation to their integration in mountain belts, with a particular emphasis on the question of the tectonic/thermal inheritance. He handled different methodologies, including geological mapping, structural analysis and kinematic modelling of fold-thrust structures. This approach recently includes mechanical validation of kinematic models in collaboration with Pauline Souloumiac. His regional knowledge comprises the geology of North Africa, the Arabian Plate and the Mediterranean area. Dominique is the author or coauthor of more than 150 papers in scientific journals and 2 continental tectonic maps (Africa and Arabia together with Pascale Leturmy). He considers that long distance correlations are useful tools to defend a global approach in geology.
Pascale Leturmy is associated-professor at CY Cergy Paris Université since 1999 in the department of Geosciences and Environment. She is specialized in structural geology and worked on several fold-and-thrust belts like the front of Himalaya (PhD thesis in 1997), the subandean zone, the Zagros or the North African belts. She uses several methodologies like field analysis, mapping (the continental map of Arabia and surrounding areas published with Dominique Frizon de Lamotte), balanced cross section or numerical modeling to explore interactions between tectonic and sedimentation. More recently, in collaboration with Pauline Souloumiac, she involves mechanical analysis to explore fold-and-thrust belts evolution.
Pauline Souloumiac is associated-professor at CY Cergy Paris Université since 2011 in the department of Geosciences and Environment. Her research field focus on the development of new methods of numerical simulations to treat the deformation of frictional sediments of the upper crust. In parallel, she works out an analogue modelling laboratory dedicated to the validation of numerical simulations. The main objective of her research is to introduce mechanical concepts in the understanding of geological structures like fold-and-thrust belts or accretionary wedges. This methodology named tectono-mechanics is conducted in close collaboration with structural geologists like Pascale Leturmy and Dominique Frizon de Lamotte.
Adrien Frizon de Lamotte is draughtsman at at CY Cergy Paris Université. After two years as student in an Architecture School in Paris, he became metalworker in a family company. A serious health problem led him to a professional reorientation toward computer assisted conception and computer assisted [...] draughtsmanship (CAC-CAD). Since 2018, he is in charge of CAC-CAD and 3D printing for the U-Maker project developing 3D models and prints for the pedagogy in Earth Sciences.