An Atlanta Journal-Constitution poll shows Gov. Nathan Deal opening up a small lead over Democrat Jason Carter , while fellow Republican David Perdue has an advantage within the margin of error over Democrat Michelle Nunn in the U.S. Senate race.

The poll, conducted by Abt SRBI of New York of 1,170 Georgians from Oct. 16-23, shows no candidate in Georgia's top two races approaching 50 percent of likely voters. With Libertarian candidates pulling away a small but significant chunk of voters, runoffs loom for both races. The toplines:

For governor:

-- Deal, 46 percent;

-- Carter, 41 percent;

-- Libertarian Andrew Hunt, 5 percent;

For U.S. Senate:

-- Perdue, 44 percent;

-- Nunn, 42 percent;

-- Libertarian Amanda Swafford 6 percent

The much-discussed proportion of the African-American vote is 29 percent in the AJC survey -- between the 2010 and 2012 turnout numbers for this group. Women measure in at just under 50 percent. Female voters represented 55 percent of the 2010 general election balloting.

The poll, a "gold standard" live caller survey of 1,170 Georgians this week, is of a mix of cell phone and land-line users. Its margin of error for likely voters is +/- 3.6 percentage points.

An interactive look at all of the crosstabs and methodology for the AJC poll can be found here.

CNN/ORC is out with another live-caller survey this morning showing the Democrats slightly ahead, though its sample size is half as large as the AJC poll. Channel 2 Action News is set to release an automated poll with Landmark Communications later today.

While there has been some variation in the polls of late, there has been movement in Deal's direction in the governor's race and Nunn's way in the Senate race, while both remain tight and no one has hit 50 percent yet.

For a more detailed look at the AJC ‘s polling, check out our coverage this weekend in the paper and on MyAJC.com.