Terrestrial (Int Cal04) and Marine (Marine04) radiocarbon calibration curves for the past 26,000 cal yr BP. Calibrated ages are shown for 1σ and 2σ (68.2% and 95.4% confidence levels, respectively).
Details Calibration of a radiocarbon age of 6550 ± 40 BP of a terrestrial sample from the Northern Hemisphere, using Int Cal04 calibration curve and Ox Cal program version 3.10.
1) with a known value of regional offset from the global marine model age for that sample, defined as R and R of a location are usually assumed constant through time.
In addition, are there any locally or regionally available marine reservoir corrections? Be sure to incorporate these adjustments into your calibrations, if necessary, and provide a list of the offset that you used.
Alternatively, you may choose to use another calibration program such as Ox Cal to calibrate and/or report your dates.
A benefit of using Ox Cal is that the graphs are easier to interpret and to use in presentations, although as far as your instructor is concerned, the software itself is not as intuitive to use as CALIB.
Ox Cal 3.9v Let's use Ox Cal v.3.9 to calibrate a sample from Trinidad (OS-49084) using the terrestrial (intcal98.14c) dataset option. File: Analysis Options Choose your "Reporting" option (e.g., BP or BC/AD) Choose your sigma "Range" Click "Browse" and select the appropriate Radiocarbon Calibration Curve (e.g., intcal98.14C for terrestrial samples or marine98.14C for marine samples).
When presenting your results, be sure to round off to the nearest "10". Be sure to consider the following: The CALIB program can also plot these results on a graph.
To do this, you need to scroll down until you find the box shown below.
These variations are due to changes in ocean circulation and the carbon cycles associated with climatic change.
Temporal variations in C was artificially produced when hundreds of nuclear test weapons were detonated in the atmosphere, mostly in the Northern Hemisphere, in the late 1950s and early 1960s.
The difference of the two curves (R) is ~400 yr on average.