有机地球化学（英文：Organic geochemistry）是生物在地球上的影响和过程的探讨。有机地球化学的研究要追溯到有机地球化学之父Alfred E. Treibs的研究。 Treibs第一个从石油分离出金属紫质。这个发现让原本不太知道起源的石油确信是从生物而来。金属紫质通常为稳定的有机化合物，从这些萃取衍生物的细部结构可以得知他们的来源是叶绿素。

沉积矿床中蕴含的有机化合物和石油蕴含量之间的关系是我们所好奇的。研究古沉积物和岩石提供石油化学的起源和来源还有生命在生化上的来历。

现代的有机地球化学包含研究近代沉积物来了解碳循环、气候变迁和海洋的过程。

Organic geochemistry is the study of the impacts and processes that organisms have had on the Earth. The study of organic geochemistry is usually traced to the work of Alfred E. Treibs, "the father of organic geochemistry." Treibs first isolated metalloporphyrins from petroleum. This discovery established the biological origin of petroleum, which was previously poorly understood. Metalloporphyrins in general are highly stable organic compounds, and the detailed structures of the extracted derivatives made clear that they originated from chlorophyll.