The northbound lanes of I-75 in Henry County were blocked until mid-afternoon Thursday while authorities investigated a late-morning fatal wreck involving a motorcycle and a tractor-trailer.

The wreck happened about a mile south of I-675. The lanes reopened around 3 p.m.

The wreck occurred when a southbound truck crossed the median and collided with a northbound motorcycle, killing the motorcyclist. The name of the victim had not been released. Police were attempting to notify the next of kin, said Sgt. Joey Smith of the Henry County police.

The cause of the wreck is under investigation.

The state Department of Transportation reported shortly after noon that northbound traffic was backed up seven miles, while southbound traffic was jammed for three miles approaching the wreck site.