Relative dating of rocks ppt
I believe a solution that has been completely overlooked for far too long is Visual Paradigm.
It's closed source, but it has a free community edition (non-commercial use) and is very stable and polished. Many of the suggestions in other answers are good stand-ins for Visio for general diagramming.
It's also available to download here if you just want the OO/Lib O extension.
Edit: Now also added to extensions.and extensions.I also like y Ed very much: it has a straightforward approach to creating diagrams and lets you work efficiently after a very short while.
Output can (depending on input) look as professional as necessary. It has the option to "Make connector avoid selected objects".
However, y Ed requires an Oracle Sun Java VM, which is not standard e.g. There are some online alternatives but most of them have paid subscriptions.
The country's different volcano and lava types originate from different tectonic settings and types of volcanic eruptions, ranging from passive lava eruptions to violent explosive eruptions.
Canada has a rich record of very large volumes of magmatic rock called large igneous provinces.
Like other Hawaiian eruptions, the relative volume of ejected pyroclastic material is less than that of all other eruption types.
The main phenomenons during Hawaiian eruptions is steady lava fountaining and the production of thin lava flows that eventually build up into large, broad shield volcanoes.