"were presumably formed" is correct and usable in written English.
You can use it when you are suggesting that something happened without having any definitive proof. For example: The mountain ridges we see today were presumably formed millions of years ago.
The Cr- and Fe-rich bcc regions were presumably formed by spinodal decomposition of a Cr Fe phase that was inherited from the hot compacted state.
Abundant pores in pseudomorphic volcanic texture of grains from the silica pyrite and silica pyrite ± alunite ± kaolin associations (Fig. 3c, d) were presumably formed by defection of original crystals such as plagioclase and pyroxene during chemical leaching by highly acidic fluid, although some of pores probably reflect the original vesicular texture typically observed in volcanic rocks.
In fact, we also showed that the NB-associated proteins turned out to consist of calcium or apatite binding proteins found in the medium in which NB were presumably formed.
Histological analysis of H&E-stained H&E-stainedeslideshat the tumor consuggested blood-filled vessel-like sthatthees tumorwere presumably formed by neoplasticonsistedlial cells.
These preferences were presumably formed by a response habit, that is, by sticking to the first rewarded technique (Crast et al. 2010).
Functions of individual domains rather than those of the whole proteins are analyzed, since the first enzymatic domains were presumably formed from the simple primordial peptides with elementary functions [ 9].
Both HSO4−SO42− and S2O62− are presumably formed (and adsorbed) on gold upon electrooxidation of aqueous SO2.
The latter was presumably formed by polarisation of the polymer between edges of two neighbouring graphene platelets.
6′-sialyllactose was presumably formed from α-2,3 bound sialic acid in the casein glycomacropeptide as well as from 3′-sialyllactose produced in the reaction.
Interpreting the K horizon as a shear zone also implies that it is not directly related to an intrusion (i.e. a heat source) and was presumably formed by repeated tectonic events over a long period of time.
The Quetta Syntaxis is presumably formed as a result of an oroclinal bend in these mountain belts (Fig. 1) and is expected to serve as a junction for thrust faults.
