Course:EOSC311/2024/The Evolution of Geology and Food Preparation

Summary

Rocks, minerals, and other geological resources have been acquired and used for food preparation over millions of years. Rocks have been available for widespread use, for example, cutting tools, due to the many accessible deposits worldwide. Archaeologists use various methods to analyze and extrapolate data from artifacts to investigate the economic and social behaviours of human beings through time. In contemporary times, lithic resources undergo several processes that transform them into household essentials such as kitchen countertops and appliances. This Wiki page aims to discuss various types of rocks and minerals acquired from Earth that have contributed to food culture around the world over many generations.

Overview of the Geologic Time Scale.

Statement of Connection

This topic was inspired by the content introduced early in the EOSC 311 course, particularly learning about different rocks and minerals and the rock cycle in Module 2. As my major focuses on studies around food and nutrition, I was inspired to explore a topic that closely relates to my daily life. We rarely think about the materials and resources that make up our everyday tools and items we interact with, so this project helped bring my attention to Earth’s resources that I rely on daily. After brainstorming how various rocks and minerals are used in modern-day household kitchens, I expanded my research to include the history of geological resources throughout several time periods. In Module 2, we also gained a basic understanding of the Geological Time Scale; this allowed me to build connections between various lithic artifacts and their potential uses in ancient times. This project relates to multiple course learning objectives, including exploring the relationship between minerals and rocks, describing the rock cycle, and discussing how and where igneous and metamorphic rocks form and their relationship to mineralization.

Types of Rocks and How They Are Formed

Rocks consist of a natural mix of minerals, mineraloids, and organic matter; they are classified based on the formation process of the rock. The properties of a rock, such as its minerals, grain size, shape, and texture, influence its characteristics.

Basalt is a type of extrusive igneous rock known for its mafic mineral composition, which includes high iron and magnesium contents.

• Sedimentary rocks: These rocks are formed when the accumulation and deposition of organic particles and sediment in bodies of water becomes buried, loses water, and is cemented to form rock; this process is called diagenesis. Sedimentation occurs in four stages: transportation, deposition, burial, and lithification. Four types of sedimentary rocks include clastic, chemical, biochemical, and organic.
• Igneous rocks: These volcanic rocks form when existing rocks melt and molten magma cools. Magma is composed of molten minerals and trapped volatiles like water, carbon dioxide, and sulphur dioxide. Intrusive igneous rocks cool slowly beneath the Earth's surface, allowing for the development of larger crystals over time as they are uplifted to the surface. Examples include granite, gabbro, and peridotite. Extrusive igneous rocks cool rapidly when lava erupts from a volcano, resulting in the formation of tiny crystals only. Examples include basalt, obsidian, and rhyolite.
• Metamorphic rocks: These rocks are transformed from existing rocks to form new rocks under increased pressure and temperature. The parent rocks may be sedimentary, igneous, or metamorphic. Metamorphic rocks can be classified as foliated or non-foliated. Foliated metamorphic rocks, such as slate, phyllite, schist, and gneiss, have a sheet-like structure where minerals are aligned due to the pressure during formation. Non-foliated rocks, such as marble and quartzite, do not have an aligned mineral structure since they are made under conditions with low and uniform pressure.

Resources Obtained From Earth

Early humans used hunting and gathering techniques with simple stone and bone tools to hunt woolly mammoths, deer, and bison. They also gathered berries, fruits, and nuts to complement their meals. Natural lithic resources were valued for their unique properties, making them suitable for the harsh actions of grinding and chopping. Over the past couple of centuries, resources have been obtained and industrially processed into more advanced tools, such as mechanical appliances. However, such evolving technology still relies on the basic elements and minerals produced within the Earth, emphasizing the importance of Earth's natural processes and the need to sustain these valuable resources.

Obsidian cliff fragment from the Pleistocene Epoch in Wyoming, USA.

Crystalline quartz crystals.

Aluminum: This element is the most abundant metal in Earth’s crust, but its metallic form does not exist in nature. Aluminum is found naturally as bauxite, a mixture of aluminum oxides bonded with water. Pure aluminum is soft and weak, whereas commercial aluminum alloys containing small amounts of silicon and iron are hard and strong. “Aluminum is an excellent conductor of heat and electricity” and is ductile and highly malleable. Since 5000 BCE, Mesopotamians, Egyptians, and Babylonians have used aluminum compounds for pottery, medicine, and textiles. During the 18th century, aluminum was recognized for its metallic properties and has since been isolated for aluminum processing.

Chert and flint: These sedimentary rocks were ideal source materials for tools and weapons during the Stone Age. Their fine grain and conchoidal fracture make them easy to shape into arrowheads, spears, and flaking tools. Chert and flint can be found in rocks of all ages, making them a reliable resource throughout history.

Granite: A coarse-grained intrusive igneous rock that primarily contains quartz and feldspar. Granite may form in dykes, sills, and batholiths and contain other minerals such as muscovite, biotite, amphibole, and pyroxene.

Marble: A metamorphic rock, often transformed from granular limestone, that can be easily carved and sculpted. Marble often contains accessory minerals and igneous intrusions, such as small grains of quartz, mica, graphite, iron oxides, and pyrite; "these minerals represent impurities in the original limestone, which reacted during metamorphism to form new compounds". Physical deformation and chemical decomposition of metamorphic marbles often result in various colours, patterns, and veined appearances. The primary mineral in marble is calcite, which determines its hardness and light transmission properties.

Obsidian: This extrusive igneous rock has been a key material throughout history for making weapons and tools for early peoples. Its conchoidal fracture has smooth, curved surfaces and sharp edges, making it an ideal material for arrowheads.

Quartz: Quartz is composed of oxygen and silicon atoms that bond to form tetrahedrons, which build crystals. Crystalline quartz has visible crystals, while cryptocrystalline quartz has microscopic or hidden crystals. Quartz is the primary mineral found in sand because of its hardness and resistance to weathering.

Tools Over Time

Researchers believe that the toolmaking of simple hand tools, adzes, scrapers, and cleavers began with Australopithecus, a species of early primates in South Africa, during the Pliocene Epoch, 5.3 million to 2.6 million years ago. The Paleolithic Period, also known as the Stone Age, began around 2.6 million years ago; it is known for the ancient development of human technology, particularly the creation of stone tools.

Various flake tool artifacts made from flint.

Archaeologists have found that prehistoric people commonly used lithic tools for cutting, scraping, and drilling on materials such as hide, bone, and wood. Common lithic artifacts found by archaeologists include tools made from flint, a sedimentary rock, and obsidian, an extrusive igneous rock. Functional analysis research methods help archaeologists determine the type of lithic materials used, the actions performed by the tools, and the materials these actions were carried out on.

Glass jars used to store and preserve food.

Pebble tools are the oldest type of cutting tool, often used as a chopping blade or hunting knife. A rounded stone is chipped away at one end, creating a serrated edge, and is used to grub roots and cut through animal skins and sinews. Hand axes are a more advanced and sharper version of the pebble chopper. Axes are used for chopping, splitting, and chipping. They were first made of stone and wood during the Stone Ages but then evolved in Egypt with copper, bronze, and iron blades throughout the Middle Ages. In the modern day, axes are now often made of steel.  

Flaked stone tools were often made from sedimentary and igneous rocks rich in silica and with a glassy lustre, such as chert and obsidian. These siliceous stones contain microscopic cracks, making them easy to chip. When the fracture stress is overloaded, the material breaks to produce the flake tool. Prehistoric humans depended on food processing techniques, such as grinding and pounding, as farming communities developed stone tool technologies. Currently, rocks are a cost-effective and highly available resource compared to other conventional cutting materials; the low energy production of rocks for cutting tools promotes greater sustainability concerning climate change.

Since ancient times, glass has been used for several different practical objects. Tableware items such as dishes, cups, bowls, and lamps were made of varying qualities of glass during the Roman Empire. Today, glass is a staple material in the food industry, making up essential items such as drinking cups, food storage containers, plates, and more.

Lithic resources are commonly used for various food preparation processes in home kitchens and restaurants. Mineral resources, such as granite and marble, are often used for kitchen countertops. Factors influencing consumer decision-making for furnishing materials include colours, patterns, and textures. Minerals are finite resources, contributing to the sustainability consciousness in the manufacturing processes of these materials.

Additionally, small amounts of aluminum are added to other metals and alloys to construct appliances for specific uses. Refrigerators, cooking utensils, and electrical food processing equipment may contain aluminum-based alloys with added metals and silicon. Aluminum processing prepares the ore for use in various products. Common uses for aluminum products include aluminum cans for perishable food items and aluminum foil for packaging leftovers.

Food preservation techniques have evolved over time to prevent food spoilage. The oldest preservation methods include drying, refrigerating, and fermenting, and some more modern techniques include canning, pasteurizing, and freezing. Appliances such as ovens, freezers, and blenders have become staple items in household kitchens worldwide, contributing to the ease of safely preparing and storing food.

Cultural Impacts

Porous lava rock used commonly used in fire pits.

Preparation of Mexican food in clay pots.

Taste and texture of food are critical aspects of cultural cuisines. A major factor influencing these cuisines is the country's climate, as it determines the raw materials available for use. Major ingredients and cooking processes help categorize different cuisines; for example, in the Mediterranean, traditional ingredients include lamb, olive oil, lemons, peppers, and rice. Similarly, in South America, fresh and dried corn are staple ingredients. In Hawaii, the ancient practice of using an imu, an underground pit oven, to slow-cook large animals, typically pigs, is a traditional cooking practice that brings people together. Native Hawaiians perform this practice by covering the cooking pit with heated basalt or lava rocks. When layered in the cooking pit with large banana tree leaves, the porous nature of the volcanic rocks retains and redistributes heat to steam the animal carcass. The same types of lava rocks have become more popular for backyard firepits in recent years. Gas fire pits use porous lava rocks to distribute heat and are often used for campfires and roasting marshmallows. In Latin American cuisine, clay pots, traditionally known as cazuelas, are often used to prepare healthy and flavourful meals. Clay baking dishes are resistant to heat and cook food evenly, and they are typically used for simmering, stewing, or braising beans and rice. Paella, a traditional Spanish dish made of saffron-seasoned rice, meats, seafood, and vegetables, was originally made in shallow clay pots and cooked over a fire. The porous composition of clay allows food to cook evenly and become more seasoned from natural juices with each use. Cooking with traditional clay pots also contributes a feeling of nostalgia and cultural connection compared to other metal cookware and appliances such as the Instant Pot.

Spears and bow-and-arrows were frequently utilized by hunting-gathering groups in the Congo Basin rainforest region to hunt wild pigs, birds, and monkeys. In Taiwan, Indigenous groups relied on these same tools to hunt deer, wild boar, mountain goats, and black bears. Other hunting-gathering groups in Asia used these tools to hunt large fish and reptiles, demonstrating the versatility and convenience of these tools for diverse cultural groups over the years.

Conclusion / Your Evaluation of the Connections

Earth supplies a diversity of natural resources that have allowed humans and other organisms to survive over many generations. Rocks and minerals form the foundation of various landscapes and ecosystems, providing habitats, but they also play an essential role in food acquisition and consumption. Throughout this research project, I have learned about the versatility of rocks for different purposes, including hunting wildlife, preparing produce, and serving food. I enjoyed exploring more about cultural cuisines around the world and learning about the traditional ingredients and cooking methods that bring families and communities together.

Rocks form over millions of years, indicating they are finite resources that should not be taken advantage of. Researchers are raising awareness of the need for sustainable practices in extracting and processing lithic resources, as industrial activities over the past few centuries have had significant environmental impacts. Throughout history, rocks and minerals have been an integral part of social and technological development, and it was fascinating to learn about human evolution from a geological perspective.

References

This Earth Science resource was created by Course:EOSC311.