Most of the oil we use today was formed from plankton and algae. Hint: Dinosaurs aren't considered to be a type of either plankton or algae!
And how do you explain human remains found more than six thousand years ago? The oldest fossil of anatomically modern humans have been found in Africa and dated as around 195,000 years old. The earliest human art appears about 75,000 years ago. We've found jewelry made from ostrich eggs dated to 50,000 years ago. We have sculptures and cave paintings that are around 40,000 years old. Human beings first reached Australia and New Guinea around 35,000 years ago. Human beings probably arrived in the Americas about 14,500 years old (although some postulate human beings arrived earlier). We know that human beings first discovered agriculture in Mesopotamia around 10,000 BC. People first began domesticating plants and animals around 8500 BC in Southeast Asia, around 7500 BC in China, around 7000 BC in the Indus valley and around 6000 BC in Egypt. Farming began in Europe around 5000 BC. The Copper Age started in Mesopotamia around 6000 BC. We have Sumerian pottery dating to around 6000 BC. We've found temples made around 5100 BC in southern Mesopotamia.
And you, you think that mankind was created only 6000 years ago? I'm sorry, but we have evidence of human art, culture, and civilization that goes back beyond 4000 BC. How do you deal with this evidence? Do you just dismiss the dating methods as flawed? But we use radio-carbon dating for much of this. And radiocarbon dating is a form of radiometric dating. And it's radiometric dating that allows us to know that the dinosaurs existed millions of years ago. Why not dismiss that too? This is completely inconsistent. Young Earth Creationists are at least more consistent when it comes to bloody stupid denialism.
(The sources I used for dates come from Wikipedia and from Guns, Germs, and Steel. I consider the latter a very reliable source, but I also realize that there may have been new developments since its publication. As for Wikipedia, I tried to make sure that there was a reliable source cited for any given date before I copied it down. However, I could have made a mistake, misunderstood something, made a mistake about the reliability of a certain citation, etc. So if I have made any mistakes in this comment, I'd be grateful for any corrections.)