Study of mantle structure in southeast Canada and the northeast US offers an excellent opportunity to address this issue because the region spans 3 billion years of Earth history, including Archean formation of the Superior craton and younger accretion of terranes to eastern Laurentia during the Proterozoic Grenville and Phanerozoic Appalachian orogenies. The unique physical and chemical properties of cratonic lithosphere are thought to be key to its long-term survival and its resistance to pervasive modification by tectonic processes. Similarly, plates with large portions of continental or cratonic area with RMS velocities exceeding ∼15 cm/yr for more than ∼10 Myr should be considered as potential artefacts requiring further justification of plate driving forces in such scenarios. Based on the post-Pangea plate motions, one principle that can be applied to pre-Pangea times is that plates with less than ∼50% continental area can reach RMS velocities of ∼20cm/yr, while plates with more than 50% continental fraction do not exceed RMS velocities of ∼10cm/yr. By evaluating factors influencing plate speeds over the Mesozoic and Cenozoic, our temporal analysis reveals simple principles that can guide the construction and evaluation of absolute plate motion models for times before the Cretaceous in the absence of hotspot tracks and seafloor spreading histories. We also find that short-lived (up to ∼10Myr) rapid accelerations of Africa (∼100 and 65Ma), North America (∼100 and 55Ma) and India (∼130, 80 and 65Ma) appear to be correlated with plume head arrivals as recorded by large igneous province (LIPs) emplacement. The slower motion of continental plates is compatible with deep keels impinging on asthenospheric flow and increasing shear traction, thus anchoring the plate in the more viscous mantle transition zone. More generally, oceanic plates tend to move 2–3 times faster than continental plates, consistent with predictions of numerical models of mantle convection. The fastest plates (∼8.5cm/yrRMS speed) have little continental fraction and tend to be bounded by subduction zones, while the slowest plates (∼2.6–2.8cm/yrRMS speed) have large continental fractions and usually have little to no subducting part of plate perimeter. Plates with any cratonic portion have a median RMS velocity of ∼5.8cm/yr, while plates with more than 25% of cratonic area have a median RMS speed of ∼2.8cm/yr. Linking tectonothermal ages of continental lithosphere to the RMS plate velocity analysis, we find that the increasing portions of plate area composed of continental and/or cratonic lithosphere significantly reduces plate speeds. To address this shortcoming, we use a plate tectonic reconstruction approach to extract time-dependent plate velocities and geometries from which root mean square (RMS) velocities are computed, resulting in a median RMS plate speed of ∼4cm/yr over 200Myr. However, present-day velocities do not capture plate behaviour over geologically representative periods of time. Present-day plate velocities provide a snapshot of this ongoing process, and have been used to infer controlling factors on the speeds of plates and continents. #Kinemac 1.9 for mac os x#Kinemac is for Mac OS X only.The motion of plates and continents on the planet’s surface are a manifestation of long-term mantle convection and plate tectonics. Also it has been said to be 'awesome' to illustrate concepts through 3D animations at conferences, schools and universities. Kinemac uses the latest technologies like the OpenGL engine, QuickTime and the Cocoa frameworks, making it the ideal application to create advertising for TV, trailers for movies, video-clips, instant scrolling messaging to put 'on air' in real time, video content for CD, DVD, web sites. #Kinemac 1.9 movie#The result is a professional and smooth animation which you can play in real-time/full-screen or export to a QuickTime movie file. Also, it lets you quickly create 3D Text and 2D scrolling text (RTF and RTFD) with any kind of font, color, size, shadows, embedded images.Ī powerful animation control system based on Bezier curves allows you to carefully control any aspect of the movement such as translations, rotations, resizing, fading, speed, acceleration and deceleration of any object on the stage. which you can easily animate by setting key frames. Kinemac allows you to apply images and movies onto the ready–to-use objects like cubes, cylinders, spheres, tubes, pies, rectangles, disks. Just drag your images, texts, movies and songs onto the Kinemac stage to get them into your animation. Kinemac is a real time, 3D animation and presentation program that allows you to create your own professional 3D animations with the simplicity of a 2D presentation tool.
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