Italy is a highly prospective gold exploration destination, and remains largely under-explored. Italy is host to numerous gold-antimony surface anomalies, typically associated with high-angle faults intersecting the Calcare Cavernoso, and with mineralization cropping out at unconformable thrust boundaries with the overlying Ligurian flysch units.
Italy has 32 active earth-moving operations, the majority of which are dimension stone quarries, but also mineral mines. Despite being a popular tourist destination and a region of outstanding beauty, the regional government is actively supporting mining in the region, encouraging foreign investment, which in turn, supports local financial rejuvenation. With growing unemployment and raising debts the country is looking for new revenue streams to help pull Italy from a financial crisis. One such sector is mining.
Medgold has been awarded three exploration licences in Italy, each 8 square kilometers in area, called Pietratonda and Frassine which holds two of the licences (Frassine + Grasceta) covering areal-extensive gold mineralization hosted within silicified limestones known as jasperoids. Their occurrence is controlled by steeply-dipping normal faults and low-angle thrust faults and their intersection with unconformable contacts.
Map showing the three Medgold licences in Italy, plus the broad outline of the Colline Metallifere (hashed yellow line) plus the 75 known metal occurrences in the Colline Metallifere (yellow circles)
GOLD MINERALIZATION IN ITALY
Gold mineralization in Italy has been described by sediment-hosted gold or Carlin-style deposit models, with gold related to silicified carbonates referred to as jasperoids. Mineralization formed in a shallow, epithermal environment.
Gold mineralization at Pietratonda and Frassine is sediment-hosted with an absence of volcanic or intrusive host rocks, although rhyolite plugs are described to the north, and it is part of a young magmatic province with widespread geothermal activity. Mineralization is related to silicification of carbonates with structural, lithological and possible karst controls. It is associated with strongly anomalous antimony, arsenic, mercury and thallium. Adjacent extensive argillic alteration and possible advanced argillic alteration may indicate a high sulfidation epithermal fluid for mineralization.
The target types at Pietratonda and Frassine are high- and low-grade sediment-hosted gold mineralization. In an internal report to Medgold, authored by international consultant, Dr. Richard Sillitoe, he indicates that high-grade analogues are Meikle and Deep Star in the Carlin trend of Nevada, where fault control and pre-existing karst are partial ore controls. An analogue for a jasperoid-hosted, low-grade gold deposit is Gualcamayo, Argentina, which is hosted by partially karsted massive limestone.
The sediment-hosted or Carlin-type gold deposits of Nevada are hosted by thinly bedded carbonates that are decalcified with weak silicification, particularly in structural conduits, and argillic alteration (Teal & Jackson, 2002). The high-grade, structurally-controlled deposits such as Meikle and Deep Star have stronger silicification.