The first quarter of 2017 included an impairment in our Alaska segment of $174 million for the associated PP&E carrying value of our small interest in a nonoperated producing property.

The first quarter of 2016 included impairments in our Europe and North Africa segment of $127 million, primarily as a result of lower natural gas prices in the United Kingdom.

The charges discussed below are included in the “Exploration expenses” line on our consolidated income statement and are not reflected in the table above.

In the first quarter of 2017, we recorded a before-tax impairment of $51 million for the associated carrying value of capitalized undeveloped leasehold costs of Shenandoah in deepwater Gulf of Mexico following the suspension of appraisal activity by the operator.

In the first quarter of 2016, due to lack of commerciality of a drilled well, we recorded a before-tax impairment of $95 million for the associated carrying value of capitalized undeveloped leasehold costs of the Melmar prospect in deepwater Gulf of Mexico. Additionally, following the completion of an initial marketing effort in the Gulf of Mexico, we recorded a before-tax impairment of $73 million, primarily due to changes in the estimated market value.