How would tectonics behave on a two continent planet?

Question

I am working on constructing a world which is basically (from the northern pole to the southern pole):

• smallish frozen over ocean
• huge land mass encompassing the northern hemisphere
• tremendous ocean forming an effective 'belt' dividing the planet in two halves
• slightly smaller land mass than the northern hemisphere (about 2/3 to 3/4 of it), encompassing the southern hemisphere

The planet itself will have about 1.1 times the size of earth and slightly more landmass (about 35% landmass to 65% waters), it will have 3 moons/satellites orbiting it:

Tectonic movement of plates moves from the equator to the poles, the north continent consists of roughly 3 or 4 big plates, the southern continent of about twice that amount.

The only invented material on the whole world will be a sort of crystal/compound which produces a gas when in contact with sulfuric hot water. Said gas will provide a high lifting capacity about roughly 4 to 5 times that of helium or hydrogen.

• biggest moon, about the size of earth's moon (maybe a trifle bigger) will orbit the planet along its equator
• the two smaller moons will orbit the planet at about a 60° and 70° degree inclination relative to the plane of the biggest moon (both having a mass of roughly one third of the big moon)

---

I'm neither a geologist nor biologist nor anything fancy myself sadly. So my questions are (This question originally involved a set of 5 questions, all but question 4 were removed to be asked in other questions; see related questions):

4. Is it a fair assumption for me to have most big mountain ranges positioned roughly parallel to the equator?

Answer 1

I'm going to attempt to answer question 4 as I'm neither a biologist nor an expert on tides. I have however studied geology and physics.

Firstly though, rachet freak is very correct in saying that you can't have a gas with more lifting power than hydrogen, unless magic is involved, you would have to increase the density of the atmosphere. This effect in it self might make air a more likely travel option than the land or the ocean but it's unlikely. The main issue with making airships is the material needed to construct them. A civilization would need large amounts of a strong, lightweight substance. I'll leave you to think about that one.

As for mountains, one very important factor is used to decide where mountains form: tectonics. Tectonic plates cause immense land warping forces that are capable of forming mountains such as Mount Everest. This happens either when one plate moves under another (often making volcanoes) or when two plates move towards each other and buckle.

To get the ocean ring around the centre of your planet it is likely that there is a fault line splitting two tectonic plates running around the equator of the planet. The northern and southern plates could be moving apart much like how the Americas and the Eastern continents are moving apart. If these northern and southern plates are in turn moving under further norther and southern plates there could be two rings of large mountains and volcanoes parallel to the equator.

I would suggest making a plate tectonics map of your planet to decide how oceans and mountains are being formed.

EDIT

A note going back to your question on plants, a possible idea would be to have a mountain+volcano range on one continent and not the other, leading to more fertile ground on that continent and therefore differing or more abundant plant life.

Answer 2

If you have control of the tectonic plates then you control the mountain ranges

As mountains are an emergent feature from the shape, position and motion of tectonic plates, you, the author, are free to set up the mountains ranges however you please.

Without a specific map describing the tectonic plates, their shape and motion, we can't offer specific verifications. However, it's plausible to setup tectonics to create arbitrary mountain ranges.