Looking for Copper- How are Porphyry Deposits formed?
Copper is one of the most important global infrastructure metals, and demand for it is rising. In 1980, less than 8 million tons were produced globally – a figure that more than doubled by 2019. And a recent World Bank report suggests demand for copper could rise tenfold by 2050 as the world moves toward a low-carbon future.
Reasons for increased demand include more widespread use of electronics, renewable energy infrastructure such as wind turbines and solar panels, and the integration of electric vehicles, which use 380% more copper than typical internal combustion engines.
Porphyry copper deposits account for more than 65% of global copper production, and these low grade, high tonnage deposits can stay in production for a long time. But how do we find more to meet future demand?
To begin, geologists understand the Earth’s crust to be made up of a number of “plates” that interact with each other by either colliding, pulling apart, or sliding alongside each other. In places where these plates are colliding, a process called “subduction” takes place, whereby one plate is drawn down underneath the other. As the subducted plate heats up at depth, partial melting occurs. In other words, residual water in the slab helps light elements melt and become buoyant, rising into the crust forming mountains called volcanic “arcs”.
Porphyry deposits are part of this partial melting process. At mid to upper crustal levels, a large magma chamber is formed. Porphyritic intrusions and fluids are exsolved from this magma chamber and pass upward through fractures in the rock to form a core of porphyry intrusions and potassic alteration, defined by the ubiquitous presence of potassium feldspar and biotite. Outboard of this potassic core is a halo of propylitic alteration defined by a green coloring of the rocks from the assemblage of minerals epidote, chlorite, calcite, and albite. Upward migration of residual acidic fluids results in the formation of the phyllic zone, defined by a muscovite (also called sericite), quartz, and pyrite assemblage. Finally, as acidic steam travels to the surface, clay alteration of the rocks takes place, forming the argillic alteration typically associated with the so-called “lithocap” environment.
Mineralization occurs primarily within the potassic core and overlying phyllic zone. Copper minerals such as chalcopyrite, bornite, and chalcocite occur along with gold and molybdenite in stockwork veins and disseminated in the host rock.
These predictable alteration and mineralization assemblages help guide geologists looking for copper porphyry deposits. Workers can use mapping and then drilling to define the mineral resource.
To find examples of porphyry copper exploration projects, check out the Llano Del Nogal and Ball Creek projects at .
References
Garside, M., 2020, Copper – statistics and facts,
Leyo, 2007, World production trend of copper (in million tons per year), USGS report.
Arrobas et al., 2017, The Growing Role of Minerals and Metals for a Low Carbon Future, World Bank Report,
Music from
1 view
1566
432
8 months ago 00:02:46 1
Kylie Minogue - Padam Padam (Official Video)
8 months ago 00:11:16 1
”BREAKING IN ON BRAKE PROSPERITY” 1933 RAYBESTOS ASBESTOS AUTOMOBILE BRAKES PROMO FILM XD47464
8 months ago 00:09:25 1
WATCH OUT! Why Is Everyone WORRIED About OCTOBER 4 | My Personal Opinion
8 months ago 00:18:57 1
Lift your Sagging Breasts by Gently Pinching! 🥰 3cm Uplift in 7Days🎗Prevent Breast Cancer
8 months ago 00:13:39 1
Official Strymon UltraViolet Sound Samples
8 months ago 00:04:23 1
Disturbed - The Vengeful One (Official Music Video) [4K UPGRADE]
8 months ago 00:10:59 1
26 Sep: Ukrainians BROKETHROUGH the Most Sensitive Russian LINE for 11 km | Ukraine War Update
8 months ago 00:08:42 1
Michael Becomes Morbius | Morbius (2022) | Now Scaring
8 months ago 00:04:46 1
NOVEMBER11 - Leave me now (YouTube Rocks)
8 months ago 02:05:53 1
Stive Morgan & Евгений Соколовский - The Best - My Angel
8 months ago 00:12:08 1
NEW AIRFLARE ULTIMATE TUTORIAL (2022) - COACH SAMBO
8 months ago 00:04:48 1
Disturbed - Land Of Confusion [Official Music Video]
8 months ago 00:03:25 1
Dua Lipa - Be The One (Official Music Video)
8 months ago 00:06:39 1
Let’s Fly! Stories Because of You [MV] || Genshin Impact Original Song by Reinaeiry
8 months ago 00:04:28 1
Aerosmith - Dream On (Lyrics)
8 months ago 00:08:04 1
THE INCREDIBLE PRAWNS [VEGAN]
8 months ago 00:03:50 1
Eighth Wonder - I’m Not Scared (Video)
8 months ago 00:11:48 1
🌻 SUNFLOWER GRANNY SQUARE CROCHET CARDIGAN | diy crochet pattern for beginners - full guide
8 months ago 00:02:11 1
Do This 2 Exercise For 14 Days and Look in The Mirror
8 months ago 00:03:36 1
Paramore - Running Out Of Time (Official Video)
8 months ago 00:03:07 1
A Celebration of Selfless Love!
8 months ago 00:03:54 1
Newborn Moose Taken By Grizzly Bear || ViralHog
8 months ago 00:02:14 1
972 Breakdowns On the Landway to New York (English trailer extended)
8 months ago 10:09:37 1
Beautiful singing of morning birds by the calm river. 10 Hours of 4K video.