Oil prices jumped over 7% to well over $100 per barrel when markets opened Sunday evening.Why it matters: The latest surge shows that traders don't see last week's ceasefire deal reviving large-scale tanker transit through the Strait of Hormuz — and it undoes a large amount of the price drop that followed the pause in hostilities.Continued high prices will delay major relief at U.S. gasoline pumps, where regular gasoline prices dipped slightly in recent days and currently average $4.13-per-gallon, per AAA.The latest: The global benchmark Brent crude is up by over $7 per barrel to $102.29, while WTI, the main U.S. price, is up by roughly $8 to $104.56.Catch up quick: President Trump on Sunday morning said the U.S. will impose a naval blockade on Iran and the Strait of Hormuz, several hours after peace talks in Pakistan ended in failure.Iran has effectively held the strait hostage, imposing a toll and limiting oil exports.Trump's blockade aims to flip that dynamic by denying Iran the leverage it's using as a bargaining chip and preventing it from exporting its oil, Axios' Barak Ravid reports.Data: Financial Modeling Prep; Chart: Ben Geman/AxiosWhat they're saying: "Given the continued threat of Iranian attack against any ships that don't pay the toll, the US blockade announcement will further discourage shipping through the strait, keeping volumes below 10% of the prewar level and putting continued pressure on oil prices," analysts with the Eurasia Group, a political risk analysis and consultancy, said in a note Sunday.The intrigue: "In pursuing this strategy, President Trump may be calculating that China will become more active in negotiations if it faces a cutoff of Iranian cargoes to its refineries," RBC Capital Markets Helima Croft said in a note Sunday before markets opened.What we're watching: Tehran may increase attacks on regional energy facilities if Trump backs up his blockade threat with action, writes Croft, who analyzes markets for an arm of the Royal Bank of Canada.