Care to provide a single example of a dinosaur fossil that was dated and verified by multiple independent dating methods?
Look up the Hell Creek Formation.
This formation referred to strata relating to the very late stage of the Cretaceous period in Montana, in both North and South Dakota, and even in Wyoming.
Hell Creek Formation is pretty famous because of the abundance of fossils found in these region, including large quantities of dinosaur fossils dated to Maastrichtian age, the youngest age of the Late Cretaceous epoch.
As I have told you dating rocks, minerals or fossils often used a number of dating methods, other than radiometric dating (measuring specific radioactive isotopes, eg lead, potassium, uranium, carbon, etc), which include various luminescence dating techniques, and stratigraphy.
Before the discovery of application of radiometric methods, the usual method was using stratigraphy, which studying layers of rock formation, be these rock be igneous (rocks formed from volcanic activities) or sedimentary rocks (rocks that formed from sediments of weathering of igneous rocks that have been deposited and hardened over time.
You would find fossils in sedimentary rocks, not igneous, because lava tends to destroy bones from heat and pressure.
Anyway there are numbers of specific techniques used in stratigraphy, including the studying changes in magnetic fields, from one layer to other layers. This technique is called magnetostratigraphy. It was used in Hell Creek Formation.
Because the Maastrichtian age was the last age before the Cretaceous-Paleogene Extinction Event (KPg), evidence show a thin layer of iridium deposit that marked the boundary between the lower Cretaceous stratum and the upper Paleogene stratum.
A question that you might ask me: “Why is iridium deposit is important?”
It is important because we can date when massive extinction event occurred (66 million years ago), and it provide validity that the extinction was caused, when the Earth was hit by either a large comet or asteroid.
Iridium are very rare metal to find naturally on Earth, and they are more abundantly found in comets and asteroids. The impact would have spread debris of iridium in wide regions.
This impact occurred in the Gulf of Mexico, a large crater called Chicxulub crater. This KPg boundary with the layer of iridium would be buried under sedimentary deposits of the Paleocene epoch (the first epoch of the Paleogene period).
Since all dinosaurs of the Mesozoic era (Triassic, Jurassic and Cretaceous) are found below the KPg line, then fossils found of any dinosaurs would be older than 66 million years old.
I think I am giving you too info for you to process, but if you want to talk about dinosaurs, then there is no possible way that I can keep it brief.
Also you need to understand that, not only I am not a biologist, I am also not a paleontologist or geologist. I did study one semester of geology, but it was for civil engineering, not for stratigraphy or paleontology. They didn’t teach me radiometric dating or what to do with fossils, because it was part of my subject and course.
Anyway, I would suggest you ask someone else, or to look up Hell Creek Formation, because of discovery of the rich fossils of dinosaurs and other animals.