We present a sample of 34 weak metal line absorbers at z3{sigma} detections of the SiII{lambda}1260 and CII{lambda}1334 absorption lines, with W_r_(SiII)<0.2 {AA} and W_r_(CII)5. The column densities of HI and low-ionization metal lines obtained from Voigt profile fitting are used to build simple photoionization models. The inferred densities and line-of-sight thicknesses of the absorbers are in the ranges of -3.3<logn_H_/cm^-3^-1.0(0.0). The fraction of systems showing near-/supersolar metallicity in our sample is significantly higher than in the HI-selected sample of Wotta et al., and the galaxy-selected sample of Prochaska et al., of absorbers probing the circum-galactic medium at similar redshift. A search for galaxies has revealed a significant galaxy-overdensity around these weak absorbers compared to random positions with a median impact parameter of 166 kpc from the nearest galaxy. Moreover, we find the presence of multiple galaxies in ~=80 per cent of the cases, suggesting group environments. The observed dN/dz of 0.8+/-0.2 indicates that such metal-enriched, compact, dense structures are ubiquitous in the haloes of low-z group galaxies. We suggest that these are transient structures that are related to galactic outflows and/or stripping of metal-rich gas from galaxies.

Cone search capability for table J/MNRAS/476/4965/tableb1 (List of QSO spectra with S/N>5 per pixel searched for weak MgII analogs)

Cone search capability for table J/MNRAS/476/4965/tableb2 (List of QSO spectra with S/N<5 per pixel that are not used in this study)

Cone search capability for table J/MNRAS/476/4965/tableb3 (List of strong CII/SiII systems. These systems are not part of the studied here)