Welcome to my Earthcache! An Earthcache is a special type of geocache where there is no container to find - instead you are looking for a unique geological feature of the area and need to answer questions, as well as posting a picture, in order to claim the find. The goal of this Earthcache is to educate visitors about different types of inclusion found in the rocks of Allegany State Park, including what an inclusion is and how to identify it. All observations can be made from the parking lot - there are several dozen rocks with their own unique inclusions that you can study to answer the questions. Parking is available in the immediate vicinity of the location.
EARTHCACHE REQUIREMENTS
As with all of my ECs, I am not looking for PhD thesis level responses, but I am hoping that you take some time to enjoy the area and learn something new. Please include a list of all cachers with your answer, if answering for more than one caching name. There is no need to send individual answers.
To claim a 'find' for this Earthcache you must answer the following questions and send your answers in a message or email to the owner using the link at the top of the page. You can log your find with a photo at GZ. Send your answers to the tasks. I will be in contact if there is a problem, no need to wait for a response as long as the required photo is included in your log.
Observational Task
At GZ, you will be standing in front of a row of large, unique bolders. Each of these bolders was harvested from within ASP, and is local to the area. Choose a couple of your favourite rocks, and answer the questions below based on your observations:
1. Find an example of at least five different types of vugs, veins, concretions, fossils or other inclusions (as listed below) at or within a small radius of GZ (within the parking lot). Describe what you are seeing and what makes each different one unique. Determine what type of inclusion this is, based on the descriptions below.
2. Using the information below (or your own research) please try to identify which of these would have already been present as the rock developed, which would have developed at the same time as the surrounding rock, and which would have developed or changed AFTER the surrounding rock was already formed.
3. Standing at the posted coordinates, what is the most common inclusion that you see, and why do you feel it would be the most common?
4. MANDATORY - Post a photo of yourself, your signature item, your GPS, at or near the posted coordinates, or with the Bee Hunter Pavilion sign. You do not need to show your face if you are shy. You may include this photo in your log, or send it with your answers but it must be provided as proof that you visited the area.
Earthcache Information:
THANK YOU Allegany State Park for permission to share this learning adventure. This Earthcache has undergone review and has been issued ASP Geocache Permit #AL-25-4
At GZ, you will find a series of large rocks that are used as a landscaping feature for the side of a parking lot. These rocks are no ordinary rocks - they contain a collection of vugs, iron oxide veins, slate, phenocrysts, concretions, and other deposits that include crystaline structures formed in air pockets or cracks of the rocks. All of these rocks have been sourced from within Allegany State Park, throughout various formations in the park. Within these rocks you will note many different types of rock, including quartz conglomerates, limestones, and sandstones. But, what are all of these possible inclusions, and how did they get here?
There are a myriad of processes that cause a different type of rock to be embedded within the parent rock. There are also a myriad of processes that cause different colors and markings on the parent rock, based on the minerals present as the rock was formed. These are considered Geological Inclusions or Oddities.
BLEBS and LENSES
BLEBS are small bubble-like inclusions of one mineral within a larger mineral. Blebs tend to be solid, brightly coloured, and form when magma cools quickly, causing crystals to form, trapping small amounts of the melt inside the crystal, creating a "glassy bubble".
LENSES are deposits that are thick in the middle and thin at the edges, resembling a convex lens in cross-section. These lenses can form through various geological processes, such as the accumulation of sediments in a localized area or the intrusion of magma into pre-existing rock formations. One example of a lens is a band of iron ore within a sedimentary rock, giving a dark grey (almost black) shiny line through otherwise dull and grey limestone.
CONCRETIONS
A concretion is a hard, compact mass of matter formed by the precipitation of mineral cement within the spaces between particles. They are found in clay strata that was originally mud laid down on the sea floor millions of years ago. Concretions vary in size and shape, but most are usually spherical. They can contain a variety of different minerals, and can be different colours than the host rock depending on the mineral inclusions
CALCIUM CARBONATE DISCS – These concretions aka fairy stones consist of small single or multiple discs often with concentric surface grooves. They can appear as shallow bowl-like depressions formed when calcium carbonate minerals in the rock weathered quicker than the non-calcareous parts of the rock. This process is called differential weathering.
CANNONBALL CONCRETIONS – These concretions are large round concretions resembling cannonballs. They were created by early cementation of sand and silt by calcite.
ELONGATE CONCRETIONS – Elongate concretions are hardened, often oval or cylindrical, masses of rock that form within sedimentary rocks, typically parallel to the bedding and groundwater flow, and can provide insights into past geological conditions, including paleochannel patterns and groundwater flow directions
HIATUS CONCRETIONS – These concretions are characterized by exhumation, exposure and reburial. They are most commonly found during periods in which calcite sea conditions prevailed, such as the Ordovician, Jurassic and Cretaceous. Fossils are often associated with these formations.
KANSAS POP ROCKS – These concretions are typically associated with thin layers of altered volcanic ash. Shape is generally oblate spheroids with variable sizes. Called “pop rocks” because they explode when thrown in a fire or produce sparks and a burning sulfur smell if cut or hammered.
MOQUI MARBLES – These concretions were created by the precipitation of iron dissolved in groundwater. They are varied in both shape and size.
ROSE ROCKS – These concretions are made of crystals that resemble a rose in bloom. The rock’s petal-shaped clusters is due to the intergrowth of crystals. The mineral comprising the rose was precipitated in interconnected voids in the rock.
STAINING
When metallic minerals, such as iron, are trapped inside of the host rock and then are eventually exposed to air, they can cause staining on the rock as the minerals oxodize, undergoing a chemical reaction to the air. While the staining itself is not actually an inclusion, it is the result of an inclusion - the staining gives us a way to view the presence of inclusions without breaking the host rock open. Many times, water will penetrate the rost rock, and the staining will be localized to an area surrounding the crack.
IRON – Most sedimentary rocks contain iron in varying degrees. This mineral may appear in patterns or dispersed randomly throughout the parent rock. Color appears in various reddish hues.
MANGANESE – Forms similar to iron staining, but from manganese rich solutions (water) percolating through the sandstone. This mineral may appear in patterns or dispersed randomly throughout the parent rock. Color appears in various blackish hues.
XENOLITHS and PHENOCRYSTS
Xenoliths and Phenocrysts are typically found in igneous rock, and are a result of the volcanic process. As the molten material rises, it tears off bits and pieces of the magma pipe in which it is traveling. These bits and pieces, trapped in the magma but not melting into it, become xenoliths. Crystals that are torn from the sides of magma pipes are called xenocrysts.
XENOLITHS are rock fragments of metamorphically altered rock that gets caught in the cooling magma or lava. As the magma cools, the igneous rock forms around the rock fragments.
PHENOCRYSTS are mineral crystals in igneous rock that began growing early in the cooling history of the rock, before the fine-grained groundmass crystallized around them. Or they may have arrived by gravity, either floating to the top or sinking to the bottom of a magma chamber.
VUGS
A vug is a small to medium-sized cavity inside rock. It may be formed through a variety of processes, but most commonly are cracks and fissures opened by movement (either tectonic or seismic activity), which are partially filled by quartz, calcite, and other minerals. Open spaces within ancient rocks or lava collapse breccias are another important source of vugs. These types of vugs are typically caused by minerals or sediment located within the pockets, which crystalize under intense pressure. Vugs may also form when crystals or fossils inside a rock are removed through erosion or dissolution processes such as decaying organic matter, leaving behind holes with organic or mineral compounds. The inner surfaces of such vugs are often coated with a crystal druse (a coating of fine crystals on a rock fracture surface, vein or within a vug).
VEINS
In geology, a vein is a sheetlike body of minerals within a rock. Veins form when minerals are carried by fluids within the rock mass and deposited through precipitation. The flow is usually due to the fluid circulation.
OPEN-SPACE FILLING - Veins formed in this way may exhibit a colloform, agate-like habit, of minerals which radiate out from nucleation points on the vein walls and appear to fill up the available open space. Geodes, vugs, and cavities are all examples of open-space filling phenomena in hydrothermal systems.
CRACK-SEAL FILLING - veins are thought to form quite quickly during deformation by precipitation of minerals within incipient fractures. Generally the space is in the order of millimeters or micrometers. Veins grow in thickness by reopening of the vein fracture and progressive deposition of minerals on the growth surface.
There are many other inclusions, or items that appear similar to inclusions, that may be found in these rocks, such as:
FOSSILS
Formed when a plant or animal dies and is buried in mud and silt. Soft tissues quickly decompose leaving the hard bones or shells behind. Over time sediment builds over the top and hardens into rock. A relatively common occurrence is white calcite replacing the shell.
ORGANICS
Rocks are often covered with lichen and other organics, which sometimes appear like inclusions. These organic materials will continue to grow and take over the surface of the rock, but are not true inclusions of the rock.
Take your time to observe the rocks here, and determine just how many different types of inclusions you can indetify in this small area.
Details About this Earthcache
Parking is available right beside the rocks you will be looking at in this area, with plenty of parking for multiple vehciles. Due to the visual nature of earthcaches, I would ask that you please limit your visit to daylight hours. This park is open seasonally. Please note: there is a paid entrance fee to access the park during the peak season, starting Memorial Day Long Weekend through to late October.
This earthcache will not be available when there is excessive snow on the ground. Please be respectful and come back when you are able to fully experience this location.
This cache was placed by a PROUD Platinum Earthcache Master.