MEXICO CITY — Two Carrollton women vacationing in Mexico fell to their deaths Sunday in a parasailing accident after the rope tying their parachute to a boat broke, authorities said.

The women, identified as Margaret Beaman, 49, and Lisa Smith, were killed when the parachute they shared was blown into a rocky area on shore where the two were pummeled by rocks and palm trees, authorities said Monday. The cause of death was head and body trauma. Ms. Smith's age was not immediately available.

The accident occurred near the Mayan ruins of Tulum, in an area known as the Riviera Maya south of Cancún.

There were contradictory reports about a third woman in the group, identified as Sally Uhrig.

The director of civil protection in Tulum, Lucio Salvador Arguea, said some witnesses indicated that a third woman, presumably Ms. Uhrig, was also parasailing and may have fallen into the ocean and was saved by the parasailing boat.

But a higher-ranking investigator, speaking on condition of anonymity, said Ms. Uhrig was on board the parasailing boat from the beginning of the outing and was a relative of one of the women in the parachute above her.

The news service Noticaribe said that Ms. Uhrig had planned to parasail with the other two women but that their combined weight exceeded regulations, so she stayed on shore.

A clerk at the Grand Palladium Kantenah hotel said the three women arrived together on Saturday and planned to stay for a week. Ms. Uhrig checked out Monday, the clerk said.

Mr. Arguea said the captain of the boat and others were clearly negligent. Authorities had closed the area to all boats because of turbulent waters and unpredictable winds, he said.

“The boat pulling the parachute did not take any security measures since every day we have been informing people that all navigation was closed,” he said.

Once the women’s parachute broke from the boat, it quickly headed toward shore, where the two victims crashed.

“It seems they hit the water in a rocky area, and then they were elevated again and became trapped in a palm tree,” Mr. Arguea said.

The captain of the boat ordered his assistant off the boat after the parachute broke loose and left the scene, Mr. Arguea said. He said police had detained the parasailing service providers as part of their investigation.

In another Mexico boating accident this year, Lisa Chung, 18, of Grand Prairie died after she and her high school friends were forced to jump into the sea near Cancún when their snorkeling vessel began to sink.

Ms. Chung was apparently trapped underwater by a rescue boat and suffered heart and lung failure. She died three days later in a Dallas hospital.

Staff writer Marissa Alanis in Dallas and news assistant Javier García in Mexico City contributed to this report.