The Mineral Evolution database is currently under development.
The goal of this page is to present localities at which the mineral is found, and estimates of the oldest possible geologic age of the minerals at these localities.
This mineral is using an age reported as an element mineralization period.
O
This mineral is using an age calculated from all data at the locality.
R
The age displayed for this mineral originates from a different, non-child locality.
P
The age displayed for this mineral is the range of ages for this mineral at all of this locality's children.
This mineral's age has not yet been recorded.
This Mineral list contains entries from this locality, including sub-localities. Minerals in bold are reported by mindat.org as occurring directly at this locality, and do not occur at any children (sublocalities) of this locality.Elements at this locality, including sub-localities: CCaCuFeHMgOPbSSiSnElements from minerals reported directly at this locality: Structural Groups for minerals in this locality:
Omitting the lithium mica granite sample from the regression makes little difference to the value of the age and intercept but beecause of the reduced spread in Rb/Sr ratiosn the errors are slightly increased.
Statistically acceptable whole rock and/or mineral isochrons were obtained for each of the granites studies and a preliminary inspection of the tata may suggst several episodes of of Hercynian magmatism in SW England. The first, c.. 290 generated the Carnmenellis, Bodmin and St Austell granites and was succeeded some 10 Ma by the Dartmoor grantie, and finally the intrusion of the Land's End granite at 270 Ma. The emplacement of the porphyry dyke and the main phase of mineralization, would then be closely associated with the second and third magmatic episodes. However more detailed examintation of the data and comparison with other work reveals certain major discrepencies in the hypothesis.