Oceanic transform faults (OTFs) are prominent linear features in the ocean-basins, offsetting mid-ocean ridges by tens to several hundreds of kilometers and hence juxtaposing oceanic lithosphere of contrasting age (Fox & Gallo, 1984 Wilson, 1965). Our observation evidences extensional tectonics at OTFs. Comparison of correlations suggests that age-offset scales better with the morphological parameters, along with scatters mostly at small age-offsets, indicating small-age-offset OTFs are unstable due to their weak lithospheric strength. We find that correlations between morphological features and spreading rate are rather weak. Moreover, correlations between these morphological parameters and related tectonic factors (e.g., spreading rate, age-offset) were investigated in this study. Using the most complete and advanced compilation of bathymetric data from ultraslow- to intermediate-spreading ridges, we parameterized the morphological characteristics of OTFs and extracted length, width and depth for each transform fault from the compiled bathymetric data. Block diagram and map view for Question 7.In the past 5 decades, studies on oceanic transform faults (OTFs) have revealed significant complexity in their morphology, which calls for detailed quantitative analysis to study the processes controlling the morphology of OTFs. Right Lateral Transform Fault.ģD interactive model of Figure 17: Figure 18. This is true no matter which block you are standing on, because it is relative motion! Sometimes, transform faults will be marked with the relative motion directions on either side of the fault (Figures 17 and 18). In a right-lateral transform fault, your friend on the opposite block moves towards your right. In a left-lateral transform fault, your friend on the opposite block moves towards your left. Imagine you are standing on one side of a transform fault looking across the fault to a friend on the other side. The fault plane can be vertical or at an angle ( Figures 17 and 18). In transform or strike-slip faults, one block moves laterally relative to the other block – it does not matter which one is the hanging wall or footwall. Thrust Fault.ģD interactive model of Figure 16: Transform or Strike-slip Faults Reverse Fault.Ī reverse fault that has a shallowly dipping fault plane (perhaps less than about 45 degrees) is called a thrust fault (Figure 16). In map view, the hanging wall rocks will be older than the footwall rocks, due to erosion of the uplifted side ( Figure 15). This motion can be determined by tracing the offset of the beds in a vertical motion in a block diagram. In reverse faults, the hanging wall moves upwards relative to the footwall. Normal Fault.ģD interactive model of Figure 14: Reverse Faults In map view, the hanging wall rocks will be younger than the footwall rocks, due to erosion of the uplifted side. In normal faults, the hanging wall moves downward relative to the footwall ( Figure 13 and Figure 14). There are three main types of faults: normal faults, reverse faults, and transform or strike-slip faults. A good way to remember this is to imagine a mine tunnel running along a fault the hanging wall would be where a miner would hang a lantern and the footwall would be at the miner’s feet.įigure 13 (Click on link): Hanging wall, footwall, and scarp of a normal fault. In a dip-slip system, the footwallis below the fault plane and the hanging wall is above the fault plane. Dip-slip motion consists of relative up-and-down movement along a dipping fault between two blocks, the hanging wall and footwall. Normal and reverse faults display vertical, also known as dip-slip, motion. If it is visible at the surface, it is called a fault scarp (Figure 13). The plane along which motion occurs is called the fault plane. Faults are the places in the crust where brittle deformation occurs as two blocks of rocks move relative to one another.
0 Comments
Leave a Reply. |