Not an answer, but I've thought the same thing! Valles Marineris is usually described as being a rift valley caused by the crust splitting. But for the most part it is very straight - with parallel straight valleys - and resembles a deep "scratch" as if some body or bodies have hit it at a very oblique angle, ploughed a furrow, before either leaving Mars or breaking up.
Is this possible?
The Mariana Trench was formed by the Pacific Plate subducting beneath the Mariana Plate. This subduction process created the deep trench in the western Pacific Ocean.
When two tectonic plates collide, several natural landforms can be created, primarily mountain ranges and deep ocean trenches. For instance, the collision of continental plates often leads to the uplift of mountain ranges, such as the Himalayas formed by the collision of the Indian and Eurasian plates. In contrast, when an oceanic plate collides with a continental plate, it can create deep ocean trenches and volcanic arcs, like the Mariana Trench and the Andes Mountains, respectively.
Trenches such as the Peru-Chile trench are found at destructive (also known as convergent) subductive plate margins where the denser oceanic plate is being subducted beneath the lighter continental plate. Trenches are common at subduction zones.
When one tectonic plate moves under another, a trench is created. This process, known as subduction, occurs at convergent plate boundaries where an oceanic plate is forced beneath a continental or another oceanic plate. The subduction zone forms a deep oceanic trench, which is often associated with geological activity such as earthquakes and volcanic eruptions. The mantle beneath the plates may also be affected, but the direct result of this interaction at the surface is the formation of a trench.
Mars has the tallest known mountain in the solar system, Olympus Mons, which is nearly 22 km tall. Mauna Kea, the largest mountain on earth (measured from base to peak, not from sea-level) is only 10 km by comparison. Everest, the tallest mountain on Earth, only clocks in at a measly 4 km. Mars also has one of the deepest known valleys, Valles Marinaris, which can reach depths of 7 km in some places. However, Earth takes the lead with the Romanche Trench, a section of the Atlantic ocean that drops to a crushing 7.8 km deep. Of course, very little is known about the outer planets, and given the sheer scale of Jupiter and Saturn, we could make some assumptions about what lies beneath the thick gas layers.
trench
The Trench was created in 1999-05.
Tim Trench was created in 1968.
Sylvia Trench was created in 1962.
Turtle Trench was created on 2012-01-27.
The Trench - film - was created on 1999-09-17.
Ever After - Marianas Trench album - was created in 604.
Beside You - Marianas Trench song - was created in 2020-09.
Marianas Trench Marine National Monument was created in 2009.
Trenches are formed by divergent plates, Whereas Ridges are formed by plate in collision.
Cross My Heart - Marianas Trench song - was created in 2008-12.
Trenches are formed by divergent plates, Whereas Ridges are formed by plate in collision.