Radio carbon dating can not be used on "older rocks" i can't remember the exact age but anything older than a couple of Ma is not possible. the only methods u could use would be to a) get a rough evolutionary age from any insects etc trapped in the amber or b) dating the surrounding sediment in which the amber is found either by magnetostratigraphy or biostratigraphy... 
err.. whats a flat iron? like an iron for ironing clothes?!  they're Los Mallos de Riglos near Huesca in north Spain. They're alluvial fan deposits sourced from the Pyrenees - really beautiful and the view from the top is stunning with beautiful eagles and vultures... 
ok.. well, i find them interesting! the first one is a subterranean social wasp nest found within a palaeosol in overbank deposits (Late Oligocene-Miocene, Ebro Basin) and the second is a subterranean termite nest, note the coalesced chambers, in alluvial fan deposits (!) of Miocene sediments (again ebro basin)
yes, where continents collide you get mountain chains, for example the collision of Africa with Europe that is ongoing has resulted in the Alps and the Pyrenees; the northward movement of the India into Asia has resulted in the Himalayas. However, rifting (the breaking apart of crust)forces the continents apart e.g. the increasing separation of Africa/Europe from the Americas along the mid Atlantic ridge, or the breakup of east Africa along the great rift. Currently the overall trend is for continents to break up, but they will eventually come back together. not quite sure what you mean by "other stuff"! :-)
for example the island of Surtsey off the south coast of iceland formed between 1963 and 1967 from a series of volcanic eruptions. The island is the size of 1.4 km2 already diminished from around 2.7 km2 at the time of formation.. so islands- even fairly large ones can come and go pretty rapidly!
yes, what you say is correct, however, the sediment load can vary significantly seasonally. Are you after the river that can carry the maximum possible sediment load at any one time? or the river that carries the highest mean sediment load for say a year? I have asked around if anyone knows the answer (we're academic geologists of one type or another! ). There is a suggestion that a river in a glaciated area may carry the highest sed load seasonally but that a river such as the Bramahputra may carry the average highest sed load..