Whether or not something is in a geographical region is uniquely determined by its associated longitude and latitude coordinates relative to the surface of the earth (assuming it's near the surface; not too far below or above, and plate tectonics or other phenomena have not significantly altered the shape of the land masses on earth). Similarly, whether or not something is in a time period is uniquely determined the its related date(s) (or projected date if it was prior to human history).
In other words we have the following analogy: "Geographical coordinates" is to "Region" as "Time coordinates" is to "???"
I can think of the following single-word substitutions in that analogy (you can find the referenced definitions on dictionary.com; this website didn't like my lack of reputation in combination with the links I was providing):
- era: "the period of time to which anything belongs or is to be assigned:"
- epoch: "a particular period of time marked by distinctive features, events, etc."
- period: "any specified division or portion of time"
- age: "a particular period of history, as distinguished from others; a historical epoch"
The problem with those words is they are nouns and you are looking for an adjective, I think, so I'm not sure if they help.
That being said, "Wiltshire" -> "county in South West England", "Brittany" -> "north-west of France", "Moray -> council areas of Scotland", so I would describe those as "geographically western European" as their main related trait, not "geographical" in the general sense. You would need to have varied locations (including up to continents) and varied sizes of boundaries and types (i.e. unless you wanted me to think "officially sanctioned political boundaries" as a commonality, you would need to include some geographical regions that aren't sanctioned by political boundaries and some smaller ones, lest I think of macro-only).
In the same way, I came to a different main related trait for your first example. When I look at the set of "nuclear weapon use", "data storage format wars" and "major crusades" I think of competing factions of humans (without the "data storage" one, I would have thought "physically violent", as well), not things that are primarily associated with an agreed upon significant historical time period. "Nuclear weapon use", for one, (without specifying something else to make it World War II) could span many, many years/time periods - even ones that that haven't happened yet. There are some things that are strongly associated with a time period, usually something significant that happened politically, scientifically, religiously, etc. to cause a change to warrant a new label by historians.
I say that not to argue with your association to say you're wrong - more to say I don't see where you're coming from - I start with anything I can quickly think of that the semantics of the words have in common and cross of everything from that list that doesn't have a counter-example, which the length of that minimum list can be a lot to hone in on a specific concept. Now if you added a requirement like "what single word best describes what this set has in common", I might choose the most simple "significant" pattern, but in the first one I would have picked "European". Anyway if you can help clear up my misunderstanding I might be able to help find an adjective that meets your needs if the nouns I supplied (or other answers) didn't help you to your satisfaction.